java.sql.SQLException: hat Verbindung bereits nach der ersten Datenbankabfrage geschlossen

Question

Meine Konfigurationen sind: Application Server: Weblogic 10gR3 Datenbank: Oracle 10g IDE: Netbeans Java: Version 7

Ich bin vor Ausnahme während Verbindung vom Pool erhalten. Ich habe es mit Ressourcen versucht, um die Last zu vermeiden, Verbindungen und Anweisungen falsch zu schließen.

Hier ist der Stack-Trace.

[INFO] 2016-06-24 19:01:08,304 org.nmdc.incentivepackage.databaseFiles.DepositMDao checkData 184 - Executing query SELECT count(*) count FROM dep_m 
[INFO] 2016-06-24 19:01:08,304 org.nmdc.incentivepackage.databaseFiles.DepositMDao checkData 188 - Executing query SELECT count(*) count FROM dep_m 
[INFO] 2016-06-24 19:01:08,320 org.nmdc.incentivepackage.databaseFiles.DepositMDao checkData 194 - Relinquish Database connection ... 
[INFO] 2016-06-24 19:01:08,320 org.nmdc.incentivepackage.databaseFiles.DepositMDao checkData 206 - return 1###success### 
[INFO] 2016-06-24 19:01:08,320 org.nmdc.incentivepackage.controllerFiles.CheckDepositMDataController processRequest 35 - result 1###success### .........save 
[INFO] 2016-06-24 19:01:08,320 org.nmdc.incentivepackage.controllerFiles.CheckDepositMDataController processRequest 46 - update deposit master table 
[INFO] 2016-06-24 19:01:08,320 org.nmdc.incentivepackage.controllerFiles.GetDepositMDataController processRequest 33 - Fetching deposit master data 
[ERROR] 2016-06-24 19:01:08,320 org.nmdc.incentivepackage.databaseFiles.DepositMDao getDepositMData 239 - Exception 
java.sql.SQLException: Connection has already been closed. 
at weblogic.jdbc.wrapper.PoolConnection.checkConnection(PoolConnection.java:55) 
at weblogic.jdbc.wrapper.Connection.preInvocationHandler(Connection.java:92) 
at weblogic.jdbc.wrapper.Connection.createStatement(Connection.java:441) 
at org.nmdc.incentivepackage.databaseFiles.DepositMDao.getDepositMData(DepositMDao.java:219) 
at org.nmdc.incentivepackage.controllerFiles.GetDepositMDataController.processRequest(GetDepositMDataController.java:35) 
at org.nmdc.incentivepackage.controllerFiles.GetDepositMDataController.doPost(GetDepositMDataController.java:74) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820) 
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) 
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125) 
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292) 
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:175) 
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3498) 
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) 
at weblogic.security.service.SecurityManager.runAs(Unknown Source) 
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2180) 
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2086) 
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1406) 
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201) 
at weblogic.work.ExecuteThread.run(ExecuteThread.java:173) 

Die DBUtility Klasse, die das Verbindungsobjekt gibt, ist

public class DBUtility { 
    private static Connection conn; 
    private static Context ctx ; 
    final static Logger logger = LoggerFactory.getLogger(DBUtility.class); 

    public DBUtility() { 
    ctx = null;    
    conn = null;   
    } 

    public static Connection getConnection() throws Exception { 
    if (conn != null) 
     return conn; 
    else {    
      //Hashtable ht = new Hashtable(); 
      // ht.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory"); 
     // ht.put(Context.PROVIDER_URL,"t3://localhost:7001"); //weblogic server   
      try {     
      ctx = new InitialContext(); 
      javax.sql.DataSource ds = (javax.sql.DataSource) ctx.lookup ("incentivepool"); 
      conn = ds.getConnection();     
      } 
      catch(Exception e) { 
      logger.error("Error in establishing connection...",e); 
      } 
    } 

    return conn; 
    } 
} 

Die Klasse, die Ausnahme ist

werfen wird

ublic class DepositMDao extends HttpServlet { 

private Connection connection = null; 
final static Logger log = LoggerFactory.getLogger(DepositMDao.class); 
private String deposit,category,period,query; 
private float amount; 
private String errors,status; 
private int errorCount; 
private Statement statement; 
private ResultSet rs; 
JSONObject jobject; 

public DepositMDao() throws Exception { 
    // connection = DBUtility.getConnection(); 
    if(connection != null) { 
     log.info("Received Database connection ..."); 
    } 
    errors =""; 
    status = "success"; 
    errorCount =0; 
    statement = null; 
} 
public String checkData() throws SQLException { 
    int count=0; 
    query = "SELECT count(*) count FROM dep_m" ; 
    log.info("Executing query "+query); 
    try (Connection connection = DBUtility.getConnection(); 
     Statement statement = connection.createStatement(); 
     ) {   
     log.info("Executing query "+query); 
     try (ResultSet rs = statement.executeQuery(query)) {      
      if(rs.next()) { 
       count = rs.getInt("count"); 
      }    
     } 
     log.info("Relinquish Database connection ..."); 
    } catch(Exception ex) { 
     errorCount++; 
     errors = errors + " "+ex.getMessage(); 
     log.error("Exception ",ex);   
    }  

    if(errorCount == 0) { 
     status = "success";   
    } else { 
     status = "failure";   
    } 
    log.info("return "+count+"###"+status + "###"+errors); 
    return count+"###"+status + "###"+errors; 
} 

public List<DepositMBean> getDepositMData() throws SQLException { 

List<DepositMBean> depositList = new ArrayList(); 
DepositMBean depositBean; 
String dep14,dep11C,dep11B; 
depositBean = null; 
depositList = null; 
query = "SELECT c_dep14,c_dep11C,c_dep11B FROM dep_m ";  
try (Connection connection1 = DBUtility.getConnection(); 
     Statement statement1 = connection1.createStatement(); 
     ) 
    {   
     log.info("Executing query "+query); 
     try (ResultSet rs1 = statement1.executeQuery(query)) { 
      while (rs1.next()) { 
       depositBean = new DepositMBean(); 
       dep14 = rs1.getString("c_dep14"); 
       dep11C = rs1.getString("c_dep11C"); 
       dep11B = rs1.getString("c_dep11B"); 

       depositBean.setcDep14(dep14); 
       depositBean.setcDep11B(dep11B); 
       depositBean.setcDep11C(dep11C);    
       depositList.add(depositBean);    
      }  
      depositBean.display(); 
      log.info("Relinquish Database connection ..."); 
     } 
    } catch(Exception ex) { 
     log.error("Exception ",ex);   
    } 
return depositList;  
} 

Pooling-Konfiguration auf dem Server:

Answer 1

es ist, weil die Verbindung statisches Objekt ist, was bedeutet, dass NUR EINE Verbindungsinstanz existiert.

private static Connection conn 

so das erste Mal, wenn Sie es anrufen funktioniert aber das zweite Mal nicht, weil die Verbindung bereits geschlossen ist.

müssen Sie die Verbindung neu erstellen, wenn es

if (conn != null && !conn.isClosed()) 
    return conn; 

geschlossen