java实现数据库连接池（连接池的管理用了了享元模式）

package com.bbkj.DbUtils;

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

/**
 * Created by Administrator on 2016/12/7.
 */
public interface IConnectionPool {
    // 获得连接
    public Connection getConnection();
    // 获得当前连接
    public Connection getCurrentConnecton();
    // 回收连接
    public void releaseConn(Connection conn) throws SQLException;
    // 销毁清空
    public void destroy();
    // 连接池是活动状态
    public boolean isActive();
    // 定时器，检查连接池
    public void cheackPool();
}

 

package com.bbkj.DbUtils;

import com.bbkj.common.DBbean;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;
import java.util.Vector;

/**
 * Created by Administrator on 2016/12/7.
 */
public class ConnectionPool implements IConnectionPool {

    //连接池配置属性
    private DBbean dbBean;
    private boolean isActive =  false;//数据连接获得状态
    private int contActive = 0;//记录创建的总的练级数
    //空闲连接
    private List<Connection> freeConnection = new Vector<Connection>();
    //活动连接
    private List<Connection> activeConnection = new Vector<Connection>();

    //将线程和连接绑定，保证事务能统一执行
    private static ThreadLocal<Connection> threadLocal = new ThreadLocal<Connection>();

    public ConnectionPool(DBbean dbBean) {
        super();
        this.dbBean = dbBean;
        init();
        cheackPool();
    }


    // 初始化
    public void init() {
        try {
            Class.forName(dbBean.getDriverName());
            for (int i = 0; i < dbBean.getInitConnections(); i++) {
                Connection conn;
                conn = newConnection();
                // 初始化最小连接数
                if (conn != null) {
                    freeConnection.add(conn);
                    contActive++;
                }
            }
            isActive = true;
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }


    public synchronized  Connection getConnection() {
        Connection conn = null;
        try {
            // 判断是否超过最大连接数限制
            if(contActive < this.dbBean.getMaxActiveConnections()){
                if (freeConnection.size() > 0) {
                    conn = freeConnection.get(0);
                    if (conn != null) {
                        threadLocal.set(conn);
                    }
                    freeConnection.remove(0);
                } else {
                    conn = newConnection();
                }

            }else{
                // 继续获得连接,直到从新获得连接
                wait(this.dbBean.getConnTimeOut());
                conn = getConnection();
            }
            if (isValid(conn)) {
                activeConnection.add(conn);
                contActive ++;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return conn;
    }

    public Connection getCurrentConnecton() {
        // 默认线程里面取
        Connection conn = threadLocal.get();
        if(!isValid(conn)){
            conn = getConnection();
        }
        return conn;
    }

    // 获得新连接
    private synchronized Connection newConnection()
            throws ClassNotFoundException, SQLException {
        Connection conn = null;
        if (dbBean != null) {
            Class.forName(dbBean.getDriverName());
            conn = DriverManager.getConnection(dbBean.getUrl(),
                    dbBean.getUserName(), dbBean.getPassword());
        }
        return conn;
    }

    // 释放连接
    public synchronized  void releaseConn(Connection conn) throws SQLException {
        if (isValid(conn)&& !(freeConnection.size() > dbBean.getMaxConnections())) {
            freeConnection.add(conn);
            activeConnection.remove(conn);
            contActive --;
            threadLocal.remove();
            // 唤醒所有正待等待的线程，去抢连接
            notifyAll();
        }
    }

    //销毁连接池
    public synchronized  void destroy() {
        for (Connection conn : freeConnection) {
            try {
                if (isValid(conn)) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        for (Connection conn : activeConnection) {
            try {
                if (isValid(conn)) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        isActive = false;
        contActive = 0;
    }

    // 连接池状态
    public boolean isActive() {
        return isActive;
    }

    // 判断连接是否可用
    private boolean isValid(Connection conn) {
        try {
            if (conn == null || conn.isClosed()) {
                return false;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return true;
    }

    // 定时检查连接池情况
    public void cheackPool() {
        if(dbBean.isCheakPool()){
            new Timer().schedule(new TimerTask() {
                @Override
                public void run() {
                    // 1.对线程里面的连接状态
                    // 2.连接池最小 最大连接数
                    // 3.其他状态进行检查，因为这里还需要写几个线程管理的类，暂时就不添加了
                    System.out.println("空线池连接数："+freeConnection.size());
                    System.out.println("活动连接数：："+activeConnection.size());
                    System.out.println("总的连接数："+contActive);
                }
            },dbBean.getLazyCheck(),dbBean.getPeriodCheck());
        }
    }
}

 

package com.bbkj.DbUtils;

import com.bbkj.common.DBbean;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by Administrator on 2016/12/7.
 */
public class DBInitInfo {
    public  static List<DBbean> beans = null;
    static{
        beans = new ArrayList<DBbean>();
        // 这里数据 可以从xml 等配置文件进行获取
        // 为了测试，这里我直接写死
        DBbean beanOracle = new DBbean();
        beanOracle.setDriverName("oracle.jdbc.driver.OracleDriver");
        beanOracle.setUrl("jdbc:oracle:thin:@10.248.2.111:1521:orcl");
        beanOracle.setUserName("etrackchb");
        beanOracle.setPassword("etrackchb");

        beanOracle.setMinConnections(5);
        beanOracle.setMaxConnections(100);

        beanOracle.setPoolName("oraclePool");
        beans.add(beanOracle);
    }
}

 

package com.bbkj.DbUtils;

import com.bbkj.common.DBbean;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.Hashtable;

/**
 * Created by Administrator on 2016/12/7.
 */
public class ConnectionPoolManager {
    // 连接池存放
    public Hashtable<String,IConnectionPool> pools = new Hashtable<String, IConnectionPool>();

    // 初始化
    private ConnectionPoolManager(){
        init();
    }

    // 单例实现
    public static ConnectionPoolManager getInstance(){
        return Singtonle.instance;
    }
    private static class Singtonle {
        private static ConnectionPoolManager instance =  new ConnectionPoolManager();
    }

    // 初始化所有的连接池
    public void init(){
        for(int i =0;i<DBInitInfo.beans.size();i++){
            DBbean bean = DBInitInfo.beans.get(i);
            ConnectionPool pool = new ConnectionPool(bean);
            if(pool != null){
                pools.put(bean.getPoolName(), pool);
                System.out.println("Info:Init connection successed ->" +bean.getPoolName());
            }
        }
    }

    // 获得连接,根据连接池名字 获得连接
    public Connection getConnection(String poolName){
        Connection conn = null;
        if(pools.size()>0 && pools.containsKey(poolName)){
            conn = getPool(poolName).getConnection();
        }else{
            System.out.println("Error:Can't find this connecion pool ->"+poolName);
        }
        return conn;
    }

    // 关闭，回收连接
    public void close(String poolName,Connection conn){
        IConnectionPool pool = getPool(poolName);
        try {
            if(pool != null){
                pool.releaseConn(conn);
            }
        } catch (SQLException e) {
            System.out.println("连接池已经销毁");
            e.printStackTrace();
        }
    }

    // 清空连接池
    public void destroy(String poolName){
        IConnectionPool pool = getPool(poolName);
        if(pool != null){
            pool.destroy();
        }
    }

    // 获得连接池
    public IConnectionPool getPool(String poolName){
        IConnectionPool pool = null;
        if(pools.size() > 0){
            pool = pools.get(poolName);
        }
        return pool;
    }



}

使用 ConnectionPoolManager 即可调用。