连接池的基本实现

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对于池的概念，大家都不陌生，储存昂贵的资源，比如线程，jdbc连接，线程池有现成的，这里就不献丑了，主要写下连接池吧

连接池类

public class ConnectionPool {private static volatile ConnectionPool connPool;private static final String url = "jdbc:mysql://localhost:3306/java?        user=root&password=root&useUnicode=true&characterEncoding=UTF8";private final List<Connection> list = new ArrayList<Connection>();private final PoolState poolState = new PoolState();private int totalConnect;private ConnectionPool(){}static{ try {Class.forName("com.mysql.jdbc.Driver");} catch (ClassNotFoundException e) {e.printStackTrace();}}public static ConnectionPool getInstance(){if(connPool == null){synchronized (ConnectionPool.class) {if(connPool == null){connPool = new ConnectionPool();}}}return connPool;}public synchronized Connection getConnection() throws Exception{int idleConnectCount = list.size();poolState.setIdleConnectCount(idleConnectCount);if(idleConnectCount == 0 && totalConnect != 10){ return createConnection();}else if(idleConnectCount != 0){Connection connection = list.get(0);list.remove(0);return connection;}else{throw new Exception("pool is full and connect all use");}}private Connection createConnection(){Connection connection = null;try {connection = DriverManager.getConnection(url);totalConnect++;} catch (SQLException e) {e.printStackTrace();}return connection;}public synchronized void release(Connection connection){//1000毫秒if(poolState.getIdleWorkCount(1000) > 0){try {connection.close();//销毁连接totalConnect--;} catch (SQLException e) {e.printStackTrace();}}else{//缓存连接list.add(connection);}}}

连接状态类

package com.wangliyong.tool.connpool;public class PoolState {private long duration;private int idleConnectCount;public void setIdleConnectCount(int idleConnectCount) {if(this.idleConnectCount <=2 && idleConnectCount > 2){duration = System.currentTimeMillis();}this.idleConnectCount = idleConnectCount;}public int getIdleWorkCount(long duration) {if ((System.currentTimeMillis() - this.duration > duration)) {return (idleConnectCount - 2);}return 0;}}

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