import java.sql.Connection;
import java.sql.SQLException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

public class ConnectionFactory {
    
    private static DataSource ds = null;
    
    private ConnectionFactory() {
        
    }
    
    static {        
        try {
            Context initCtx = new InitialContext();
            Context ctx = (Context) initCtx.lookup("java:comp/env");
            ds = (DataSource)ctx.lookup("jdbc/main");
        }catch(NamingException e) {
            e.printStackTrace();
        }        
    }
    
    public static Connection getConnection() throws SQLException {
        return ds.getConnection();
    }
}

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JdbcUtil {
    
    public static void close(ResultSet rs, Statement st, Connection con) {
        close(rs);
        close(st);
        close(con);
    }    
    
    public static void close(ResultSet rs) {
        if(rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * PreparedStatement, CallableStatement 都是 Statement 的子类，可以共用这个方法
     * @param st
     */    
    public static void close(Statement st) {
        if(st != null) {
            try {
                st.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    
    public static void close(Connection con) {
        if(con != null) {
            try {
                con.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    
    private JdbcUtil() {        
    }
}

------解决方案--------------------
看样子是高并发时候多线程访问关闭连接问题，可以试用threadLocal取con关闭
而且关con可以在过滤器关，你每个方法close下，万一忘记不就资源没关么~

Java code

public class DBUtil {
    
       private static final ThreadLocal threadLocal = new ThreadLocal();

       private DBUtil()
       {
       }

       /**
        * 获取当前数据库连接
        *
        * @return
        * @throws Exception
        */
       public synchronized static Connection getCurrentConnection() throws Exception
       {
          Connection conn = (Connection) threadLocal.get();
          try
          {
             if (conn == null)
             {
                conn = ConnectionProvider.getConnection();
                conn.setAutoCommit(false);
                threadLocal.set(conn);
             }
          } catch (Exception e)
          {
             e.printStackTrace();
             throw new Exception("数据源错误...");
          }
          return conn;
       }

       public static void closeConnection() throws Exception
       {
          Connection conn = (Connection) threadLocal.get();
          if (conn != null && !conn.isClosed())
          {