tomcat运行一段就报这个错！

2009-2-23 15:09:30 org.apache.catalina.loader.WebappClassLoader loadClass
信息: Illegal access: this web application instance has been stopped already. Could not load com.mysql.jdbc.Messages. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1249)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1209)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at com.mysql.jdbc.CommunicationsException.(CommunicationsException.java:174)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2707)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2618)
at com.mysql.jdbc.MysqlIO.quit(MysqlIO.java:1337)
at com.mysql.jdbc.Connection.realClose(Connection.java:4386)
at com.mysql.jdbc.Connection.cleanup(Connection.java:1962)
at com.mysql.jdbc.Connection.finalize(Connection.java:3098)
at java.lang.ref.Finalizer.invokeFinalizeMethod(Native Method)
at java.lang.ref.Finalizer.runFinalizer(Unknown Source)
at java.lang.ref.Finalizer.access$100(Unknown Source)
at java.lang.ref.Finalizer$FinalizerThread.run(Unknown Source)

不影响使用，可是可以看出来连接关闭了。这个是什么原因造成功，之间没有什么操作！这个肯定是影响性能的！
这个和数据库连接池的配置有关系吗？我没有配置连接池！！！只是有个类！

package jdbc;
import javax.sql.DataSource;

import org.apache.commons.dbcp.ConnectionFactory;
import org.apache.commons.dbcp.DriverManagerConnectionFactory;
import org.apache.commons.dbcp.PoolableConnectionFactory;
import org.apache.commons.dbcp.PoolingDataSource;
import org.apache.commons.pool.impl.GenericObjectPool;

/*******************************************************************************

this class read properties from connectionPool.properties and contructor is a
jdbc connection pool in this connection pool we use dbcp as pool implement.
getConnection method can used to get a jdbc connection . when you want return
the connection to the pool , just call Connection.close().
sample:
Connection conn = null;
try {
conn = DB2ConnectionPool.getConnection();
//do db operation
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (null != conn)
conn.close();
} catch (Exception e) {
}
}
@author zhouHongCheng
******************************************************************************/
public class MySQLBConnectionPool {
// log file

// data source instance
public static DataSource dataSource = null;

static {
try {
dataSource = initlize();
} catch (Exception ex) {
String errorMsg = " MySQLConnectionPool initlize failed \n"
+ ex.getMessage();
```
}
```
}

/***************************************************************************
- initlize the DB2ConnectionPool.
- (1) read Driver , ConnectionURL, UserName , Password
- from DB2ConnectionPool.properties .
- (2) use those properties to initized a DataSource,
- and return it .
- **************************************************************************/
  private static DataSource initlize() throws Exception {
  String driver = "com.mysql.jdbc.Driver";
  String connectionURL = "jdbc:mysql://localhost:3306/jkhtdymb?useUnicode=true&characterEncoding=utf-8";
  String userName = "root";
  String password = "";
  int maxActive = 30;
  int maxIdle = 20;
  int maxWait = 1000;
  
  // 2. loading jdbc driver
  
  try {
  Class.forName(driver);
  System.out.println("DB connect success" );
  } catch (ClassNotFoundException e) {
  throw e;
  }
  
  // 3.initlize a pooling datasource
  return setupDataSource(connectionURL, // url
  userName, // user name
  password, // password
  maxActive, // max active connection
  maxIdle, // max idle connection
  maxWait); // max wait time
}

/***************************************************************************
- initlize a pooling DataSource
- @param String
- connectionURL - he connection url
- @param String
- usrName - the user name
- @param String
- ```
       password - the password
```
  **************************************************************************/
  private static DataSource setupDataSource(String connectionURL,
  String usrName, String password, int maxActive, int maxIdle,
  int maxWait) {
  
  // First, we'll need a ObjectPool that serves as the
  // actual pool of connections.
  // We'll use a GenericObjectPool instance, although
  // any ObjectPool implementation will suffice.
  //
  GenericObjectPool connectionPool = new GenericObjectPool(null);
  connectionPool.setMaxActive(maxActive);
  connectionPool.setMaxIdle(maxIdle);
  connectionPool.setMaxWait(maxWait);
  
  //
  // Next, we'll create a ConnectionFactory that the
  // pool will use to create Connections.
  // We'll use the DriverManagerConnectionFactory,
  // using the connect string passed in the command line
  // arguments.
  //
  ConnectionFactory connectionFactory = new DriverManagerConnectionFactory(
  connectionURL, usrName, password);
  
  //
  // Now we'll create the PoolableConnectionFactory, which wraps
  // the "real" Connections created by the ConnectionFactory with
  // the classes that implement the pooling functionality.
  //
  PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(
  connectionFactory, connectionPool, null, null, false, true);
  
  //
  // Finally, we create the PoolingDriver itself,
  // passing in the object pool we created.
  //
  PoolingDataSource dataSource = new PoolingDataSource(connectionPool);
  return dataSource;
}

}
然后logic里面

private static Connection con = null;
    private static DataSource ds = MySQLBConnectionPool.dataSource;

程序里就con=ds.getConnection();
然后正常close！

请帮忙指点下！
[b]问题补充：[/b]
大哥，你的这个我看过了！
已经设置称false了！

li13609254624

怎么查看mysql数据库里面各表之间的关系图？

2条回答

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