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Search found 114 results on 5 pages for 'preparedstatement'.

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  • Tomcat JNDI Connection Pool docs - Random Connection Closed Exceptions

    - by Andy Faibishenko
    I found this in the Tomcat documentation here What I don't understand is why they close all the JDBC objects twice - once in the try{} block and once in the finally{} block. Why not just close them once in the finally{} clause? This is the relevant docs: Random Connection Closed Exceptions These can occur when one request gets a db connection from the connection pool and closes it twice. When using a connection pool, closing the connection just returns it to the pool for reuse by another request, it doesn't close the connection. And Tomcat uses multiple threads to handle concurrent requests. Here is an example of the sequence of events which could cause this error in Tomcat: Request 1 running in Thread 1 gets a db connection. Request 1 closes the db connection. The JVM switches the running thread to Thread 2 Request 2 running in Thread 2 gets a db connection (the same db connection just closed by Request 1). The JVM switches the running thread back to Thread 1 Request 1 closes the db connection a second time in a finally block. The JVM switches the running thread back to Thread 2 Request 2 Thread 2 tries to use the db connection but fails because Request 1 closed it. Here is an example of properly written code to use a db connection obtained from a connection pool: Connection conn = null; Statement stmt = null; // Or PreparedStatement if needed ResultSet rs = null; try { conn = ... get connection from connection pool ... stmt = conn.createStatement("select ..."); rs = stmt.executeQuery(); ... iterate through the result set ... rs.close(); rs = null; stmt.close(); stmt = null; conn.close(); // Return to connection pool conn = null; // Make sure we don't close it twice } catch (SQLException e) { ... deal with errors ... } finally { // Always make sure result sets and statements are closed, // and the connection is returned to the pool if (rs != null) { try { rs.close(); } catch (SQLException e) { ; } rs = null; } if (stmt != null) { try { stmt.close(); } catch (SQLException e) { ; } stmt = null; } if (conn != null) { try { conn.close(); } catch (SQLException e) { ; } conn = null; } }

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  • Connect to SQLite Database using Eclipse (Java)

    - by bnabilos
    Hello, I'm trying to connect to SQLite database with Ecplise but I have some errors. This is my Java code and the errors that I get on output. Please see if you can help me. Thank you in advance. package jdb; import java.sql.*; public class Test { public static void main(String[] args) throws Exception { Class.forName("org.sqlite.JDBC"); Connection conn = DriverManager.getConnection("jdbc:sqlite:/Applications/MAMP/db/sqlite/test.sqlite"); Statement stat = conn.createStatement(); stat.executeUpdate("drop table if exists people;"); stat.executeUpdate("create table people (name, occupation);"); PreparedStatement prep = conn.prepareStatement( "insert into people values (?, ?);"); prep.setString(1, "Gandhi"); prep.setString(2, "politics"); prep.addBatch(); prep.setString(1, "Turing"); prep.setString(2, "computers"); prep.addBatch(); prep.setString(1, "Wittgenstein"); prep.setString(2, "smartypants"); prep.addBatch(); conn.setAutoCommit(false); prep.executeBatch(); conn.setAutoCommit(true); ResultSet rs = stat.executeQuery("select * from people;"); while (rs.next()) { System.out.println("name = " + rs.getString("name")); System.out.println("job = " + rs.getString("occupation")); } rs.close(); conn.close(); } } ans that what I get in Ecplise : Exception in thread "main" java.lang.ClassNotFoundException: org.sqlite.JDBC at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:315) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:330) at java.lang.ClassLoader.loadClass(ClassLoader.java:250) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:398) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:169) at jdb.Test.main(Test.java:7) Thank you

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  • Java: Making concurrent MySQL queries from multiple clients synchronised

    - by Misha Gale
    I work at a gaming cybercafe, and we've got a system here (smartlaunch) which keeps track of game licenses. I've written a program which interfaces with this system (actually, with it's backend MySQL database). The program is meant to be run on a client PC and (1) query the database to select an unused license from the pool available, then (2) mark this license as in use by the client PC. The problem is, I've got a concurrency bug. The program is meant to be launched simultaneously on multiple machines, and when this happens, some machines often try and acquire the same license. I think that this is because steps (1) and (2) are not synchronised, i.e. one program determines that license #5 is available and selects it, but before it can mark #5 as in use another copy of the program on another PC tries to grab that same license. I've tried to solve this problem by using transactions and table locking, but it doesn't seem to make any difference - Am I doing this right? Here follows the code in question: public LicenseKey Acquire() throws SmartLaunchException, SQLException { Connection conn = SmartLaunchDB.getConnection(); int PCID = SmartLaunchDB.getCurrentPCID(); conn.createStatement().execute("LOCK TABLE `licensekeys` WRITE"); String sql = "SELECT * FROM `licensekeys` WHERE `InUseByPC` = 0 AND LicenseSetupID = ? ORDER BY `ID` DESC LIMIT 1"; PreparedStatement statement = conn.prepareStatement(sql); statement.setInt(1, this.id); ResultSet results = statement.executeQuery(); if (results.next()) { int licenseID = results.getInt("ID"); sql = "UPDATE `licensekeys` SET `InUseByPC` = ? WHERE `ID` = ?"; statement = conn.prepareStatement(sql); statement.setInt(1, PCID); statement.setInt(2, licenseID); statement.executeUpdate(); statement.close(); conn.commit(); conn.createStatement().execute("UNLOCK TABLES"); return new LicenseKey(results.getInt("ID"), this, results.getString("LicenseKey"), results.getInt("LicenseKeyType")); } else { throw new SmartLaunchException("All licenses of type " + this.name + "are in use"); } }

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  • How to upload a file into database by using Servlet?

    - by user1765496
    Hi all iam working on servlets, so i need to upload a file by using servlet as follows my code. package com.limrasoft.image.servlets; import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; import java.sql.*; @WebServlet(name="serv1",value="/s1") public class Account extends HttpServlet{ public void doPost(HttpServletRequest req,HttpServletResponse res)throws ServletException,IOException{ try{ Class.forName("oracle.jdbc.driver.OracleDriver"); Connecection con=null; try{ con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe","system","sajid"); PrintWriter pw=res.getWriter(); res.setContentType("text/html"); String s1=req.getParameter("un"); string s2=req.getParameter("pwd"); String s3=req.getParameter("g"); String s4=req.getParameter("uf"); PreparedStatement ps=con.prepareStatement("insert into account(?,?,?,?)"); ps.setString(1,s1); ps.setString(2,s2); ps.setString(3,s3); File file=new File("+s4+"); FileInputStream fis=new FileInputStream(fis); int len=(int)file.length(); ps.setBinaryStream(4,fis,len); int c=ps.executeUpdate(); if(c==0){pw.println("<h1>Registratin fail");} else{pw.println("<h1>Registration fail");} } finally{if(con!=null)con.close();} } catch(ClassNotFoundException ce){pw.println("<h1>Registration Fail");} catch(SQLException se){pw.println("<h1>Registration Fail");} pw.flush(); pw.close(); } } I have written the above code for file upload into database, but it giving error as "HTTP Status 500 - Servlet3.java (The system cannot find the file specified)" Could you plz help me to do this code,thanks in advanse.

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  • Improving performance for WRITE operation on Oracle DB in Java

    - by Lucky
    I've a typical scenario & need to understand best possible way to handle this, so here it goes - I'm developing a solution that will retrieve data from a remote SOAP based web service & will then push this data to an Oracle database on network. Also, this will be a scheduled task that will execute every 15 minutes. I've event queues on remote service that contains the INSERT/UPDATE/DELETE operations that have been done since last retrieval, & once I retrieve the events for last 15 minutes, it again add events for next retrieval. Now, its just pushing data to Oracle so all my interactions are INSERT & UPDATE statements. There are around 60 tables on Oracle with some of them having 100+ columns. Moreover, for every 15 minutes cycle there would be around 60-70 Inserts, 100+ Updates & 10-20 Deletes. This will be an executable jar file that will terminate after operation & will again start on next 15 minutes cycle. So, I need to understand how should I handle WRITE operations (best practices) to improve performance for this application as whole ? Current Test Code (on every cycle) - Connects to remote service to get events. Creates a connection with DB (single connection object). Identifies the type of operation (INSERT/UPDATE/DELETE) & table on which it is done. After above, calls the respective method based on type of operation & table. Uses Preparedstatement with positional parameters, & retrieves each column value from remote service & assigns that to statement parameters. Commits the statement & returns to get event class to process next event. Above is repeated till all the retrieved events are processed after which program closes & then starts on next cycle & everything repeats again. Thanks for help !

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  • java.io.EOFException while writing and reading froma servlet

    - by mithun1538
    Hello everyone, I have the following code on the applet side: URL servlet = new URL(appletCodeBase, "FormsServlet?form=requestRoom"); URLConnection con = servlet.openConnection(); con.setDoOutput(true); con.setDoInput(true); con.setUseCaches(false); con.setRequestProperty("Content-Type", "application/octet-stream"); ObjectOutputStream out = new ObjectOutputStream(con.getOutputStream()); out.writeObject(user);//user is an object of a serializable class out.flush(); out.close(); ObjectInputStream in = new ObjectInputStream(con.getInputStream()); status = (String)in.readObject(); in.close(); if("success".equals("status")) { JOptionPane.showMessageDialog(rootPane, "Request submitted successfully."); } else { JOptionPane.showMessageDialog(rootPane, "ERROR! Request cannot be made at this time"); } In the servlet side I recieve the code as follows: form = request.getParameter("form"); if("requestRoom".equals(form)) { String fullName, eID, reason; UserRequestingRoom user; try { in = new ObjectInputStream(request.getInputStream()); user = (UserRequestingRoom)in.readObject(); fullName = user.getFullName(); eID = user.getEID(); reason = user.getReason(); Class.forName("com.mysql.jdbc.Driver"); Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/chat_applet","root",""); PreparedStatement statement = con.prepareStatement("INSERT INTO REQCONFROOM VALUES(\"" + fullName + "\",\"" + eID + "\",\"" + reason + "\")"); statement.execute(); out = new ObjectOutputStream(response.getOutputStream()); out.writeObject("success"); out.flush(); } catch (Exception e) { e.printStackTrace(); out = new ObjectOutputStream(response.getOutputStream()); out.writeObject("fail"); out.flush(); } } When I click on the button that calls the code in the applet side, I get the following error: java.io.EOFException at java.io.ObjectInputStream$PeekInputStream.readFully(Unknown Source) at java.io.ObjectInputStream$BlockDataInputStream.readShort(Unknown Source) at java.io.ObjectInputStream.readStreamHeader(Unknown Source) at java.io.ObjectInputStream.<init>(Unknown Source) at com.org.RequestRoomForm.requestActionPerformed(RequestRoomForm.java:151) **//Line 151 is "ObjectInputStream in..." line in the applet code** at com.org.RequestRoomForm.access$000(RequestRoomForm.java:7) at com.org.RequestRoomForm$1.actionPerformed(RequestRoomForm.java:62) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.setPressed(Unknown Source) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source) at java.awt.Component.processMouseEvent(Unknown Source) at javax.swing.JComponent.processMouseEvent(Unknown Source) at java.awt.Component.processEvent(Unknown Source) at java.awt.Container.processEvent(Unknown Source) at java.awt.Component.dispatchEventImpl(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Window.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Why am I getting this error? I have flushed when I output, I have closed the connections also, yet I get the error. Any reason for this?

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  • Save blob to DB using hibernate

    - by Link123
    Hey! I tried save file to MySQL using blob with hibernate3. But I always have java.lang.UnsupportedOperationException: Blob may not be manipulated from creating session org.hibernate.lob.BlobImpl.excep(BlobImpl.java:127) Here some code. package com.uni.domain; public class File extends Identifier { private byte[] data; private String contentType; public byte[] getData() { return data; } public File() {} public void setData(byte[] photo) { this.data = photo; } public boolean isNew() { return true; } public String getContentType() { return contentType; } public void setContentType(String contentType) { this.contentType = contentType; } } package com.uni.domain; import org.hibernate.Hibernate; import org.hibernate.HibernateException; import org.hibernate.usertype.UserType; import java.io.InputStream; import java.io.OutputStream; import java.io.Serializable; import java.sql.*; import java.util.Arrays; public class PhotoType implements UserType { public int[] sqlTypes() { return new int[]{Types.BLOB}; } public Class returnedClass() { return byte[].class; } public boolean equals(Object o, Object o1) throws HibernateException { return Arrays.equals((byte[]) o, (byte[]) o1); } public int hashCode(Object o) throws HibernateException { return o.hashCode(); } public Object nullSafeGet(ResultSet resultSet, String[] strings, Object o) throws HibernateException, SQLException { Blob blob = resultSet.getBlob(strings[0]); return blob.getBytes(1, (int) blob.length()); } public void nullSafeSet(PreparedStatement st, Object value, int index) throws HibernateException, SQLException { st.setBlob(index, Hibernate.createBlob((byte[]) value)); } public Object deepCopy(Object value) { if (value == null) return null; byte[] bytes = (byte[]) value; byte[] result = new byte[bytes.length]; System.arraycopy(bytes, 0, result, 0, bytes.length); return result; } public boolean isMutable() { return true; } public Serializable disassemble(Object o) throws HibernateException { return null; . } public Object assemble(Serializable serializable, Object o) throws HibernateException { return null; . } public Object replace(Object o, Object o1, Object o2) throws HibernateException { return null; . } <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.uni.domain"> <class name="com.uni.domain.File"> <id name="id"> <generator class="native"/> </id> <property name="data" type="com.uni.domain.FleType"/> <property name="contentType"/> </class> </hibernate-mapping> Help me please. Where I’m wrong?

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  • javax.naming.NameNotFoundException: Name [comp/env] is not bound in this Context. Unable to find [comp] error with java scheduler

    - by Morgan Azhari
    What I'm trying to do is to update my database after a period of time. So I'm using java scheduler and connection pooling. I don't know why but my code only working once. It will print: init success success javax.naming.NameNotFoundException: Name [comp/env] is not bound in this Context. Unable to find [comp]. at org.apache.naming.NamingContext.lookup(NamingContext.java:820) at org.apache.naming.NamingContext.lookup(NamingContext.java:168) at org.apache.naming.SelectorContext.lookup(SelectorContext.java:158) at javax.naming.InitialContext.lookup(InitialContext.java:411) at test.Pool.main(Pool.java:25) ---> line 25 is Context envContext = (Context)initialContext.lookup("java:/comp/env"); I don't know why it only works once. I already test it if I didn't running it without java scheduler and it works fine. No error whatsoerver. Don't know why i get this error if I running it using scheduler. Hope someone can help me. My connection pooling code: public class Pool { public DataSource main() { try { InitialContext initialContext = new InitialContext(); Context envContext = (Context)initialContext.lookup("java:/comp/env"); DataSource datasource = new DataSource(); datasource = (DataSource)envContext.lookup("jdbc/test"); return datasource; } catch (Exception ex) { ex.printStackTrace(); } return null; } } my web.xml: <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <listener> <listener-class> package.test.Pool</listener-class> </listener> <resource-ref> <description>DB Connection Pooling</description> <res-ref-name>jdbc/test</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref> Context.xml: <?xml version="1.0" encoding="UTF-8"?> <Context path="/project" reloadable="true"> <Resource auth="Container" defaultReadOnly="false" driverClassName="com.mysql.jdbc.Driver" factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" initialSize="0" jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer" jmxEnabled="true" logAbandoned="true" maxActive="300" maxIdle="50" maxWait="10000" minEvictableIdleTimeMillis="300000" minIdle="30" name="jdbc/test" password="test" removeAbandoned="true" removeAbandonedTimeout="60" testOnBorrow="true" testOnReturn="false" testWhileIdle="true" timeBetweenEvictionRunsMillis="30000" type="javax.sql.DataSource" url="jdbc:mysql://localhost:3306/database?noAccessToProcedureBodies=true" username="root" validationInterval="30000" validationQuery="SELECT 1"/> </Context> my java scheduler public class Scheduler extends HttpServlet{ public void init() throws ServletException { System.out.println("init success"); try{ Scheduling_test test = new Scheduling_test(); ScheduledExecutorService executor = Executors.newScheduledThreadPool(100); ScheduledFuture future = executor.scheduleWithFixedDelay(test, 1, 60 ,TimeUnit.SECONDS); }catch(Exception e){ e.printStackTrace(); } } } Schedule_test public class Scheduling_test extends Thread implements Runnable{ public void run(){ Updating updating = new Updating(); updating.run(); } } updating public class Updating{ public void run(){ ResultSet rs = null; PreparedStatement p = null; StringBuilder sb = new StringBuilder(); Pool pool = new Pool(); Connection con = null; DataSource datasource = null; try{ datasource = pool.main(); con=datasource.getConnection(); sb.append("SELECT * FROM database"); p = con.prepareStatement(sb.toString()); rs = p.executeQuery(); rs.close(); con.close(); p.close(); datasource.close(); System.out.println("success"); }catch (Exception e){ e.printStackTrace(); } }

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  • retrieving value from database in java

    - by Akcire Atienza
    I am making AGAIN another program that retrieves the inputted data/values of fields from the database I created. but this time, my inputted value will be coming from the JtextField I created. I wonder what's wrong in here bec when I'm running it the output is always null. in this program i will convert the inputted value of my JTextField into int. here it is: public class ButtonHandler implements ActionListener { public void actionPerformed(ActionEvent e) { if(e.getSource() == extendB) { ExtensionForm extend = new ExtensionForm(); extend.setVisible(true); } else if(e.getSource()== searchB) { //get text from the textField String guest = guestIDTF.getText(); //parse the string to integer for retrieving of data int id = Integer.parseInt(guest); GuestsInfo guestInfo = new GuestsInfo(id); Room roomInfo = new Room(id); String labels[] = {guestInfo.getFirstName()+" "+guestInfo.getLastName(),""+roomInfo.getRoomNo(),roomInfo.getRoomType(),guestInfo.getTime(),"11:00"}; for(int z = 0; z<labels.length; z++) { labelDisplay[z].setText(labels[z]); } in my second class it retrieves the inputted values of fields from the database I created here's the code: import java.sql.*; public class Room { private String roomType; private int guestID, roomNo; private Connection con; private PreparedStatement statement; public Room(){ try { Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection( "jdbc:mysql://localhost:3306/3moronsdb","root",""); } catch (Exception e) { e.printStackTrace(); } } public Room(int guestsID) { this(); try{ statement = con.prepareStatement("SELECT * FROM guest WHERE guestID=?"); statement.setInt(1, guestID); ResultSet rs = statement.executeQuery(); while(rs.next()){ this.guestID = rs.getInt(1); this.roomType = rs.getString(2); this.roomNo = rs.getInt(3); } }catch(Exception e){ System.out.print(e); } } //Constructor for setting rate public Room(String roomType, int roomNo) { this(); try { statement = con.prepareStatement("Insert into room(roomType, roomNo) values(?,?)"); statement.setString(1, roomType); statement.setInt(2, roomNo); statement.executeUpdate(); } catch(Exception e) { e.printStackTrace(); return; } } //getting roomType public String getRoomType(){ return roomType; } //getting roomNo public int getRoomNo(){ return roomNo; } //getting guestID public int getGuestId(){ return guestID; } } i already insert some values in my 3moronsdb which are ( 1, Classic , 103). here's my TEST main class: public class TestMain { public static void main(String [] a){ GuestsInfo guest = new GuestsInfo(1); //note that this instantiation is the other class which i just ask the other day.. (http://stackoverflow.com/questions/12762835/retrieving-values-from-database-in-java) Room rum = new Room(1); System.out.print(rum.getRoomType()+" "+ guest.getFirstName()); } } when i'm running it it only gives me null output for the Room class but i am getting the output of the GuestsInfo class which is 'Ericka'. Can you help me guys? I know I ask this kind of problem yesterday but i really don't know what's wrong in here now..

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  • JDBC Lock a row using SELECT FOR UPDATE, doesn't work

    - by Rachid
    I am having issues with MySQL's SELECT .. FOR UPDATE, here is the query I am trying to run: SELECT * FROM tableName WHERE HostName='UnknownHost' ORDER BY UpdateTimestamp asc limit 1 FOR UPDATE After this, the concerned thread will do an UPDATE and change the HostName, which is then it should unlock the row. I am running a multi-threaded java application, so 3 threads are running this SQL statement, but when thread 1 runs this, it doesn't lock its results from thread 2 & 3. Therefore threads 2 & 3 are getting the same results and they could update the same row. Also each thread is on its own mysql connection. I'm using Innodb, with transaction-isolation = READ-COMMITTED, and the Autocommit is off before executing the select for update may I miss something? OR perhaps there is a better solution? Thanks a lot. Code : public BasicJDBCDemo() { Le_Thread newThread1=new Le_Thread(); Le_Thread newThread2=new Le_Thread(); newThread1.start(); newThread2.start(); } Thread : class Le_Thread extends Thread { public void run() { tring name = Thread.currentThread().getName(); System.out.println( name+": Debut."); long oid=Util.doSelectLockTest(name); Util.doUpdateTest(oid,name); } } Select : public static long doSelectLockTest(String threadName) { System.out.println("[OUTPUT FROM SELECT Lock ]...threadName="+threadName); PreparedStatement pst = null; ResultSet rs=null; Connection conn=null; long oid=0; try { String query = "SELECT * FROM table WHERE Host=? ORDER BY Timestamp asc limit 1 FOR UPDATE"; conn=getNewConnection(); pst = conn.prepareStatement(query); pst.setString(1, DbProperties.UnknownHost); System.out.println("pst="+threadName+"__"+pst); rs = pst.executeQuery(); if (rs.first()) { String s = rs.getString("HostName"); oid = rs.getLong("OID"); System.out.println("oid_oldest/host/threadName=="+oid+"/"+s+"/"+threadName); } } catch (SQLException ex) { ex.printStackTrace(); } finally { DBUtil.close(pst); DBUtil.close(rs); DBUtil.close(conn); } return oid; } Please help.... : Result : Thread-1: Debut. Thread-2: Debut. [OUTPUT FROM SELECT Lock ]...threadName=Thread-1 New connection.. [OUTPUT FROM SELECT Lock ]...threadName=Thread-2 New connection.. pst=Thread-2: SELECT * FROM b2biCheckPoint WHERE HostName='UnknownHost' ORDER BY UpdateTimestamp asc limit 1 FOR UPDATE pst=Thread-1: SELECT * FROM b2biCheckPoint WHERE HostName='UnknownHost' ORDER BY UpdateTimestamp asc limit 1 FOR UPDATE oid_oldest/host/threadName==1/UnknownHost/Thread-2 oid_oldest/host/threadName==1/UnknownHost/Thread-1 [Performing UPDATE] ... oid = 1, thread=Thread-2 New connection.. [Performing UPDATE] ... oid = 1, thread=Thread-1 pst_threadname=Thread-2: UPDATE b2bicheckpoint SET HostName='1_host_Thread-2',UpdateTimestamp=1294940161838 where OID = 1 New connection.. pst_threadname=Thread-1: UPDATE b2bicheckpoint SET HostName='1_host_Thread-1',UpdateTimestamp=1294940161853 where OID = 1

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  • my Search method is coming up with all nulls

    - by Epic.Distortion
    Let me give a quick explanation. I took a 5 week course through a company on Java in July. They covered basic stuff, like console app, crud operations, mysql, and n-tier architecture. Since the course ended I didn't use it much because I went back to work, and other medical reasons surfaced....blah blah. I was told by the company to make a simple program to reflect what I learned. Turns out I retained very little. I decided to make a video game starage program. It would be used to stare your video games so you wouldn't have to search your bookcase(or how ever you store your games.) It is a basic console app using the crud operations with MYSQL. I can't get my search function to actually work. I have 2 layers a Presentation layer and a Logic layer. The search method allows them to search for a game by the title. when i bring run the program and use Search it only displays the title and the rest is null. here is my Presentation layer: private static Games SearchForGame() { Logic aref = new Logic(); Games g = new Games(); Scanner scanline = new Scanner(System.in); System.out.println("Please enter the name of the game you wish to find:"); g.setTitle(scanline.nextLine()); aref.SearchGame(); System.out.println(); System.out.println("Game Id: " + g.getGameId()); System.out.println("Title: " + g.getTitle()); System.out.println("Rating: " + g.getRating()); System.out.println("Platform: "+ g.getPlatform()); System.out.println("Developer: "+ g.getDeveloper()); return g; } and here is my logic layer public Games SearchGame() { Games g = new Games(); try { Class.forName(driver).newInstance(); Connection conn = DriverManager.getConnection(url+dbName,userName,password); java.sql.PreparedStatement statement = conn.prepareStatement("SELECT GameId,Title,Rating,Platform,Developer FROM games WHERE Title=?"); statement.setString(1, g.getTitle()); ResultSet rs = statement.executeQuery(); while(rs.next()){ g.setGameId(rs.getInt("GameId")); g.setTitle(rs.getString("Title")); g.setRating(rs.getString("Rating")); g.setPlatform(rs.getString("Platform")); g.setDeveloper(rs.getString("Developer")); statement.executeUpdate(); } } catch (Exception e) { e.printStackTrace(); } return g; } here is also my last results Please enter the name of the game you wish to find: Skyrim Game Id: 0 Title: Skyrim Rating: null Platform: null Developer: null any help would be greatly appreciated and thanks in advance EDIT: here is my code for my games class public class Games { public int GameId; public String Title; public String Rating; public String Platform; public String Developer; public int getGameId() { return GameId; } public int setGameId(int gameId) { return GameId = gameId; } public String getTitle() { return Title; } public String setTitle(String title) { return Title = title; } public String getRating() { return Rating; } public void setRating(String rating) { Rating = rating; } public String getPlatform() { return Platform; } public void setPlatform(String platform) { Platform = platform; } public String getDeveloper() { return Developer; } public void setDeveloper(String developer) { Developer = developer; } }

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  • how to extract data from excel (apache poi) to put it in mysql table using jsp? [ SOLVED]

    - by Nihad KH
    I want to extract data from excel sheet to insert it into a mysql table using jsp, so far i've done this and its printing data into the outpout(using apache poi),what should i add to this code ? Output : Name Age Adress Mark 35 New york,AA Elise 22 India,bb Charlotte 45 France,cc Readexcel.jsp : <%@page import="java.sql.Statement"%> <%@page import="java.util.ArrayList"%> <%@page import="java.sql.PreparedStatement"%> <%@page import="java.sql.Connection"%> <%@page import="java.util.Date"%> <%@page import="org.apache.poi.ss.usermodel.Cell"%> <%@page import="org.apache.poi.ss.usermodel.Row"%> <%@page import="org.apache.poi.xssf.usermodel.XSSFSheet"%> <%@page import="org.apache.poi.xssf.usermodel.XSSFWorkbook"%> <%@page import="java.io.File"%> <%@page import="org.apache.commons.io.FilenameUtils"%> <%@page import="org.apache.commons.fileupload.FileItem"%> <%@page import="java.util.Iterator"%> <%@page import="java.util.List"%> <%@page import="org.apache.commons.fileupload.servlet.ServletFileUpload"%> <%@page import="org.apache.commons.fileupload.disk.DiskFileItemFactory"%> <%@page import="org.apache.commons.fileupload.FileItemFactory"%> <%@page contentType="text/html" pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>PRINT DATA FROM EXCEL FILE</title> </head> <body> <% try{ boolean ismultipart=ServletFileUpload.isMultipartContent(request); if(!ismultipart){ }else{ FileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); List items = null; try{ items = upload.parseRequest(request); }catch(Exception e){ } Iterator itr = items.iterator(); while(itr.hasNext()){ FileItem item = (FileItem)itr.next(); if(item.isFormField()){ }else{ String itemname = item.getName(); if((itemname==null || itemname.equals(""))){ continue; } String filename = FilenameUtils.getName(itemname); File f = checkExist(filename); item.write(f); try{ XSSFWorkbook workbook = new XSSFWorkbook(item.getInputStream()); XSSFSheet sheet = workbook.getSheetAt(0); Iterator<Row> rowIterator = sheet.iterator(); while (rowIterator.hasNext()){ Row row = rowIterator.next(); Iterator<Cell> cellIterator = row.cellIterator(); while (cellIterator.hasNext()) { Cell cell = cellIterator.next(); switch (cell.getCellType()){ case Cell.CELL_TYPE_NUMERIC: out.print(cell.getNumericCellValue() + "t"); break; case Cell.CELL_TYPE_STRING: out.print(cell.getStringCellValue() + "t"); break;} } out.println(""); } }catch (Exception e){ e.printStackTrace(); } } } } }catch(Exception e){ } finally { out.close(); } %> <%! private File checkExist(String fileName){ String saveFile = "D:/upload/"; File f = new File(saveFile+"/"+fileName); if(f.exists()){ StringBuffer sb = new StringBuffer(fileName); sb.insert(sb.lastIndexOf("."),"-"+new Date().getTime()); f = new File(saveFile+"/"+sb.toString()); } return f; } %> </body> </html> I've created a table in my database named EXCELDATA with the header of the excel sheet : ExcelData (Name varchar(50),age int,adress varchar(50)); what should i add to this code to get the data from the excel sheet to the mysql table ??

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  • MYSQL LIMIT not working as expected - Java

    - by Sirish
    I have this weird problem in java when trying to fetch records from MYSql database by using the limit function in the query. Not sure what went wrong or did wrong, this query is giving me a hard time. Issue - When I run this query through my java program it returns all the records and not limiting the records to 10 as given in the limit. The same query when ran in MYSql command line, it execute very well and fetches me only 10 recrods. Below is the java code and query. Any help or support is appreciated.! Java code - public UserVO getApplUserDetailsList(UserVO userVO) throws CAPDAOException { List<UserVO> returnList = null; String methodName = "getApplUserDetails()"; Session session = null; String queryString = null; Transaction transaction = null; PreparedStatement ps = null; ResultSet rs = null; if(userVO == null) { logger.writeToTivoliAlertLog(className, CAPConstants.ERROR, methodName, null, "userVO returned null. Busines validation error.!", null); throw new CAPDAOException("userVO returned null. Busines validation error.!",CAPException.BUSINESS_VALIDATION_ERROR_SECURITY); } try { returnList = new ArrayList<UserVO>(); System.out.println(""); String appusr = userVO.getAppUsrNm(); session = getSession(); transaction = session.beginTransaction(); if(userVO.getAppUsrRoleCd()!=null && !userVO.getAppUsrRoleCd().trim().equalsIgnoreCase(CAPConstants.DEFAULT_DROPDOWN_VALUE)){ queryString = "SELECT " + "APPL_USR_ID,APPL_USR_NM,APPL_USR_FRST_NM, " + "APPL_USR_LST_NM,ACCESS_ROLE_CD " + "FROM APPL_USR " + "WHERE " + "APPL_USR_NM LIKE ?"+ " AND APPL_USR_FRST_NM LIKE ?"+ " AND APPL_USR_LST_NM LIKE ?"+ " AND ACCESS_ROLE_CD = ?"+ " AND APPL_USR_ID != ?"; ps = session.connection().prepareStatement(queryString); ps.setString(1,userVO.getAppUsrNm()+CAPConstants.PERCENTILE_SYMBOL); ps.setString(2,userVO.getAppUsrFirstNm()+CAPConstants.PERCENTILE_SYMBOL); ps.setString(3,userVO.getAppUsrLastNm()+CAPConstants.PERCENTILE_SYMBOL); ps.setString(4,userVO.getAppUsrRoleCd()); ps.setInt(5, 1); } else { queryString = "SELECT " + "APPL_USR_ID,APPL_USR_NM,APPL_USR_FRST_NM, " + "APPL_USR_LST_NM,ACCESS_ROLE_CD " + "FROM APPL_USR " + "WHERE " + "APPL_USR_NM LIKE ?"+ " AND APPL_USR_FRST_NM LIKE ?"+ " AND APPL_USR_LST_NM LIKE ?"+ " AND APPL_USR_ID != ?"; ps = session.connection().prepareStatement(queryString); ps.setString(1,userVO.getAppUsrNm()+CAPConstants.PERCENTILE_SYMBOL); ps.setString(2,userVO.getAppUsrFirstNm()+CAPConstants.PERCENTILE_SYMBOL); ps.setString(3,userVO.getAppUsrLastNm()+CAPConstants.PERCENTILE_SYMBOL); ps.setInt(4, 1); } if(userVO.getQueryAction()!=null && userVO.getQueryAction().equals(CAPConstants.GET_DATA)) queryString += " ORDER BY APPL_USR_ID LIMIT " + userVO.getPAGE_MIN_LIMIT() + ", " + userVO.getPAGE_MAX_LIMIT(); else queryString += " ORDER BY APPL_USR_ID"; rs = ps.executeQuery(); if(userVO.getQueryAction()!=null && userVO.getQueryAction().equals(CAPConstants.GET_DATA)) { int tempCOunt = 0; while(rs!=null && rs.next()) { tempCOunt ++; UserVO returnVO = new UserVO(); returnVO.setAppUsrId(rs.getInt("APPL_USR_ID")); returnVO.setAppUsrNm(rs.getString("APPL_USR_NM")); returnVO.setAppUsrFirstNm(rs.getString("APPL_USR_FRST_NM")); returnVO.setAppUsrLastNm(rs.getString("APPL_USR_LST_NM")); if (rs.getString("ACCESS_ROLE_CD")!=null && rs.getString("ACCESS_ROLE_CD").trim().equalsIgnoreCase(CAPConstants.ADMINISTRATOR_ROLE_CD)) returnVO.setApplicationLevelRole("Administrator"); else if (rs.getString("ACCESS_ROLE_CD")!=null && rs.getString("ACCESS_ROLE_CD").trim().equalsIgnoreCase(CAPConstants.MAINTAINER_ROLE_CD)) returnVO.setApplicationLevelRole("Maintainer"); else if (rs.getString("ACCESS_ROLE_CD")!=null && rs.getString("ACCESS_ROLE_CD").trim().equalsIgnoreCase(CAPConstants.VIEWER_ROLE_CD)) returnVO.setApplicationLevelRole("Viewer"); else returnVO.setApplicationLevelRole("None"); returnList.add(returnVO); } System.out.println("Count >>>>>>>>>>>>>>>>>>> "+tempCOunt); userVO.setReturnListFromDB(returnList); } else { int rowcount = 0; if (rs.last()) { rowcount = rs.getRow(); rs.beforeFirst(); // not rs.first() because the rs.next() below will move on, missing the first element } userVO.setTotalRecordCount(rowcount); System.out.println("Total count of the records to be used for pagination >> "+rowcount); rowcount = 0; while(rs!=null && rs.next()) { rowcount ++; UserVO returnVO = new UserVO(); returnVO.setAppUsrId(rs.getInt("APPL_USR_ID")); returnVO.setAppUsrNm(rs.getString("APPL_USR_NM")); returnVO.setAppUsrFirstNm(rs.getString("APPL_USR_FRST_NM")); returnVO.setAppUsrLastNm(rs.getString("APPL_USR_LST_NM")); if (rs.getString("ACCESS_ROLE_CD")!=null && rs.getString("ACCESS_ROLE_CD").trim().equalsIgnoreCase(CAPConstants.ADMINISTRATOR_ROLE_CD)) returnVO.setApplicationLevelRole("Administrator"); else if (rs.getString("ACCESS_ROLE_CD")!=null && rs.getString("ACCESS_ROLE_CD").trim().equalsIgnoreCase(CAPConstants.MAINTAINER_ROLE_CD)) returnVO.setApplicationLevelRole("Maintainer"); else if (rs.getString("ACCESS_ROLE_CD")!=null && rs.getString("ACCESS_ROLE_CD").trim().equalsIgnoreCase(CAPConstants.VIEWER_ROLE_CD)) returnVO.setApplicationLevelRole("Viewer"); else returnVO.setApplicationLevelRole("None"); returnList.add(returnVO); System.out.println("Row count >>"+rowcount); if(rowcount == CAPConstants.PAGINATION_MAX_VALUE) break; } rowcount = 0; userVO.setReturnListFromDB(returnList); } System.out.println("returnList >>"+returnList); return userVO; } catch (Throwable e) { e.printStackTrace(); logger.writeToTivoliAlertLog(className, CAPConstants.ERROR, methodName, userVO.getAppUsrNm(), "Error occured while trying to fetch application user details. Printing stack trace to the log for analysis..", e); throw new CAPDAOException("Error occured while trying to fetch application user details.",CAPException.SPEXECUTION_ERROR_CODE); } finally{ closeTransactionAndSession(session,transaction); } } MYSQL Query - SELECT APPL_USR_ID,APPL_USR_NM,APPL_USR_FRST_NM, APPL_USR_LST_NM,ACCESS_ROLE_CD FROM APPL_USR WHERE APPL_USR_NM LIKE '%' AND APPL_USR_FRST_NM LIKE '%' AND APPL_USR_LST_NM LIKE '%' AND APPL_USR_ID != 1 ORDER BY APPL_USR_ID LIMIT 10, 10

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  • Slowdowns when reading from an urlconnection's inputstream (even with byte[] and buffers)

    - by user342677
    Ok so after spending two days trying to figure out the problem, and reading about dizillion articles, i finally decided to man up and ask to for some advice(my first time here). Now to the issue at hand - I am writing a program which will parse api data from a game, namely battle logs. There will be A LOT of entries in the database(20+ million) and so the parsing speed for each battle log page matters quite a bit. The pages to be parsed look like this: http://api.erepublik.com/v1/feeds/battle_logs/10000/0. (see source code if using chrome, it doesnt display the page right). It has 1000 hit entries, followed by a little battle info(lastpage will have <1000 obviously). On average, a page contains 175000 characters, UTF-8 encoding, xml format(v 1.0). Program will run locally on a good PC, memory is virtually unlimited(so that creating byte[250000] is quite ok). The format never changes, which is quite convenient. Now, I started off as usual: //global vars,class declaration skipped public WebObject(String url_string, int connection_timeout, int read_timeout, boolean redirects_allowed, String user_agent) throws java.net.MalformedURLException, java.io.IOException { // Open a URL connection java.net.URL url = new java.net.URL(url_string); java.net.URLConnection uconn = url.openConnection(); if (!(uconn instanceof java.net.HttpURLConnection)) { throw new java.lang.IllegalArgumentException("URL protocol must be HTTP"); } conn = (java.net.HttpURLConnection) uconn; conn.setConnectTimeout(connection_timeout); conn.setReadTimeout(read_timeout); conn.setInstanceFollowRedirects(redirects_allowed); conn.setRequestProperty("User-agent", user_agent); } public void executeConnection() throws IOException { try { is = conn.getInputStream(); //global var l = conn.getContentLength(); //global var } catch (Exception e) { //handling code skipped } } //getContentStream and getLength methods which just return'is' and 'l' are skipped Here is where the fun part began. I ran some profiling (using System.currentTimeMillis()) to find out what takes long ,and what doesnt. The call to this method takes only 200ms on avg public InputStream getWebPageAsStream(int battle_id, int page) throws Exception { String url = "http://api.erepublik.com/v1/feeds/battle_logs/" + battle_id + "/" + page; WebObject wobj = new WebObject(url, 10000, 10000, true, "Mozilla/5.0 " + "(Windows; U; Windows NT 5.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 ( .NET CLR 3.5.30729)"); wobj.executeConnection(); l = wobj.getContentLength(); // global variable return wobj.getContentStream(); //returns 'is' stream } 200ms is quite expected from a network operation, and i am fine with it. BUT when i parse the inputStream in any way(read it into string/use java XML parser/read it into another ByteArrayStream) the process takes over 1000ms! for example, this code takes 1000ms IF i pass the stream i got('is') above from getContentStream() directly to this method: public static Document convertToXML(InputStream is) throws ParserConfigurationException, IOException, SAXException { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); Document doc = db.parse(is); doc.getDocumentElement().normalize(); return doc; } this code too, takes around 920ms IF the initial InputStream 'is' is passed in(dont read into the code itself - it just extracts the data i need by directly counting the characters, which can be done thanks to the rigid api feed format): public static parsedBattlePage convertBattleToXMLWithoutDOM(InputStream is) throws IOException { // Point A BufferedReader br = new BufferedReader(new InputStreamReader(is)); LinkedList ll = new LinkedList(); String str = br.readLine(); while (str != null) { ll.add(str); str = br.readLine(); } if (((String) ll.get(1)).indexOf("error") != -1) { return new parsedBattlePage(null, null, true, -1); } //Point B Iterator it = ll.iterator(); it.next(); it.next(); it.next(); it.next(); String[][] hits_arr = new String[1000][4]; String t_str = (String) it.next(); String tmp = null; int j = 0; for (int i = 0; t_str.indexOf("time") != -1; i++) { hits_arr[i][0] = t_str.substring(12, t_str.length() - 11); tmp = (String) it.next(); hits_arr[i][1] = tmp.substring(14, tmp.length() - 9); tmp = (String) it.next(); hits_arr[i][2] = tmp.substring(15, tmp.length() - 10); tmp = (String) it.next(); hits_arr[i][3] = tmp.substring(18, tmp.length() - 13); it.next(); it.next(); t_str = (String) it.next(); j++; } String[] b_info_arr = new String[9]; int[] space_nums = {13, 10, 13, 11, 11, 12, 5, 10, 13}; for (int i = 0; i < space_nums.length; i++) { tmp = (String) it.next(); b_info_arr[i] = tmp.substring(space_nums[i] + 4, tmp.length() - space_nums[i] - 1); } //Point C return new parsedBattlePage(hits_arr, b_info_arr, false, j); } I have tried replacing the default BufferedReader with BufferedReader br = new BufferedReader(new InputStreamReader(is), 250000); This didnt change much. My second try was to replace the code between A and B with: Iterator it = IOUtils.lineIterator(is, "UTF-8"); Same result, except this time A-B was 0ms, and B-C was 1000ms, so then every call to it.next() must have been consuming some significant time.(IOUtils is from apache-commons-io library). And here is the culprit - the time taken to parse the stream to string, be it by an iterator or BufferedReader in ALL cases was about 1000ms, while the rest of the code took 0ms(e.g. irrelevant). This means that parsing the stream to LinkedList, or iterating over it, for some reason was eating up a lot of my system resources. question was - why? Is it just the way java is made...no...thats just stupid, so I did another experiment. In my main method I added after the getWebPageAsStream(): //Point A ba = new byte[l]; // 'l' comes from wobj.getContentLength above bytesRead = is.read(ba); //'is' is our URLConnection original InputStream offset = bytesRead; while (bytesRead != -1) { bytesRead = is.read(ba, offset - 1, l - offset); offset += bytesRead; } //Point B InputStream is2 = new ByteArrayInputStream(ba); //Now just working with 'is2' - the "copied" stream The InputStream-byte[] conversion took again 1000ms - this is the way many ppl suggested to read an InputStream, and stil it is slow. And guess what - the 2 parser methods above (convertToXML() and convertBattlePagetoXMLWithoutDOM(), when passed 'is2' instead of 'is' took, in all 4 cases, under 50ms to complete. I read a suggestion that the stream waits for connection to close before unblocking, so i tried using HttpComponentsClient 4.0 (http://hc.apache.org/httpcomponents-client/index.html) instead, but the initial InputStream took just as long to parse. e.g. this code: public InputStream getWebPageAsStream2(int battle_id, int page) throws Exception { String url = "http://api.erepublik.com/v1/feeds/battle_logs/" + battle_id + "/" + page; HttpClient httpclient = new DefaultHttpClient(); HttpGet httpget = new HttpGet(url); HttpParams p = new BasicHttpParams(); HttpConnectionParams.setSocketBufferSize(p, 250000); HttpConnectionParams.setStaleCheckingEnabled(p, false); HttpConnectionParams.setConnectionTimeout(p, 5000); httpget.setParams(p); HttpResponse response = httpclient.execute(httpget); HttpEntity entity = response.getEntity(); l = (int) entity.getContentLength(); return entity.getContent(); } took even longer to process(50ms more for just the network) and the stream parsing times remained the same. Obviously it can be instantiated so as to not create HttpClient and properties every time(faster network time), but the stream issue wont be affected by that. So we come to the center problem - why does the initial URLConnection InputStream(or HttpClient InputStream) take so long to process, while any stream of same size and content created locally is orders of magnitude faster? I mean, the initial response is already somewhere in RAM, and I cant see any good reasong why it is processed so slowly compared to when a same stream is just created from a byte[]. Considering I have to parse million of entries and thousands of pages like that, a total processing time of almost 1.5s/page seems WAY WAY too long. Any ideas? P.S. Please ask in any more code is required - the only thing I do after parsing is make a PreparedStatement and put the entries into JavaDB in packs of 1000+, and the perfomance is ok ~ 200ms/1000entries, prb could be optimized with more cache but I didnt look into it much.

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