高手看看这样写的连接池有没有用？__connection_String_public_Connection_freeConnections_

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高手看看这样写的连接池有没有用？

来源: 互联网发布时间：2015-11-09

本文导语: //利用Oracle自带的连接池类的一例 /** 封装了对数据库的连接，用于处理SQL语句。 @author:yancheng(sharetop studio) @version:1.0.0 */ package poolConn; import java.sql.*; import java.io.*; import javax.sql.*; import javax.naming.*; import oracle.jdbc....

//利用Oracle自带的连接池类的一例

/**
封装了对数据库的连接，用于处理SQL语句。
@author:yancheng(sharetop studio)
@version:1.0.0
*/
package poolConn;

import java.sql.*;
import java.io.*;
import javax.sql.*;
import javax.naming.*;
import oracle.jdbc.pool.*;

public class OraPooledSQL
{

private PooledConnection dbpool;

/**
@param ConnectionURL 连接名如: jdbc:odbc:myODBC
@param UserID 用户名
@param PassWord 用户密码
*/
public OraPooledSQL(String ConnectionURL,String UserID,String PassWord)
{

  try{

    OracleConnectionPoolDataSource ocpds = new OracleConnectionPoolDataSource();

    ocpds.setURL(/tech-qa-java/ConnectionURL/index.html);

    ocpds.setUser(UserID);

    ocpds.setPassword(PassWord);

    dbpool = ocpds.getPooledConnection();

  } catch(Exception ex) {
    System.err.println("Error in PooledSQL-construct : ");
    ex.printStackTrace(System.err);
  }
}//end OraPooledSQL

//close dbpool
protected void finalize()
{
  if( dbpool != null )
  {
    try
    {
      dbpool.close();
    }
    catch(Exception ex) {  ex.printStackTrace() ;   }
  }
}

/**
用于更新、添加或删除的SQL语句
@param SQL SQL语句字串，如：insert into tablename values(id,......)
*/
public int Update(String SQL)
{
  Statement stmt = null;
  int rc = 0;

  Connection connection = null;

  try
  {
    connection = dbpool.getConnection();
    stmt = connection.createStatement();
    rc = stmt.executeUpdate(SQL);
  }

  catch( Exception ex )
  {
    System.err.println("Error in Update - OraPooledSQL : ");
    ex.printStackTrace(System.err);
  }

  return rc;

} //end Update()

/**
用于查询的SQL语句
@param SQL SQL语句字串，如：select * from tablename
*/
public ResultSet Query(String SQL)
{
  Statement stmt = null;
  ResultSet rs = null;
  Connection connection = null;

  try
  {
    connection = dbpool.getConnection();
    stmt = connection.createStatement();
    rs = stmt.executeQuery(SQL);
  } catch( Exception ex )
  {
    System.err.println("Error in Query - SQLBean : ");
    ex.printStackTrace(System.err);
  }

  return rs;

} //end Query

} //end Class

这只是对数据库的操作，不是连接池
我给你个连接池

package myclasses;
import java.sql.*;
import java.util.*;

public class ConnectionPoolBean
{
static  String IP="192.168.0.101";
private int checkedOut; //the number of connections being used

private Vector freeConnections=new Vector();//the store of connections;
                                            //always use the first one

private int maxConn;//the up-bound of the connections available;
                     // 0 denotes no up-bound

private String sDBDriver = "oracle.jdbc.driver.OracleDriver";
private String sConnStr = "jdbc:oracle:thin:@billing:1521:hanzhou1";

public static String getWebIP()    //initialization
{
    return IP;
}

public ConnectionPoolBean()    //initialization
{
    checkedOut=0;
    maxConn=1;
}

public synchronized void freeConnection(Connection con)
          //return a connection to the ConnectionPool
{
  freeConnections.addElement(con);
  checkedOut--;
}

public synchronized Connection getConnection() throws Exception
                   //to get a usable connection;
                   // if returnvalue=null, then no connection available
{
   Connection con=null;
   if (freeConnections.size()>0) //there are connections which can be reused
   {
    con=(Connection)freeConnections.firstElement();
                            //get the first available connection
    freeConnections.removeElementAt(0);
                            //remove it from the connectionPool
    try
    {
     if (con.isClosed())    //if the connection is closed
     {
      con=getConnection();
     }
    }
    catch(SQLException e)  //if the connection is not valid
    {
      con=getConnection();
    }
  }
  else  //if there are no existing connections, then create a new one
   if (maxConn==0 || checkedOut