一个极其简陋的Datasource连接池实现

写了一段时间了,一直没提交到Nutz,哈哈. 明显没有技术含量,提上去明显找抽!

用来跑Nutz的测试,能够全部pass.

直接上代码:

package org.nutz.dao.impl;

import java.io.PrintWriter;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;

import javax.sql.DataSource;

import org.nutz.lang.Lang;

@SuppressWarnings("unchecked")
public class SimpleDataSource implements DataSource {

    private String username;
    private String password;
    private String url;

    /*保存已经建立的连接*/
    private ConcurrentLinkedQueue connQueue = new ConcurrentLinkedQueue();

    public SimpleDataSource(String url, String driverClass, String username, String password)
            throws ClassNotFoundException {
        if (driverClass != null)
            Class.forName(driverClass);
        this.url = url;
        this.username = username;
        this.password = password;
    }

    public Connection getConnection() throws SQLException {
        Connection conn = (Connection) connQueue.poll();
        if (conn != null)
            return conn;
        conn = DriverManager.getConnection(url, username, password);
        return (Connection) Proxy.newProxyInstance( SimpleDataSource.class.getClassLoader(),
                                                    new Class[]{Connection.class},
                                                    new ConnectionInvocationHandler(conn, connQueue));
    }

    public void close() throws Throwable {
        Iterator it = connQueue.iterator();
        while (it.hasNext()) {
            Connection conn = (Connection) it.next();
            synchronized (conn) {
                try {
                    conn.close();
                }
                catch (Throwable e) {}
            }
        }
    }

    protected void finalize() throws Throwable {
        close();
    }

    static class ConnectionInvocationHandler implements InvocationHandler {

        private Connection conn;

        private Queue<connection> connQueue;

        public ConnectionInvocationHandler(Connection conn, Queue</connection><connection> connQueue) {
            this.conn = conn;
            this.connQueue = connQueue;
        }

        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            if (args == null
                && "close".equals(method.getName())
                && connQueue.size() < 20
                && connQueue.offer((Connection) proxy))
                return null;
            try {
                return method.invoke(conn, args);
            }
            catch (Throwable e) {
                throw Lang.unwrapThrow(e);
            }
        }
    }

    // -------------------------------------------------------------------------
    // 其他无需实现的方法
    // -------------------------------------------------------------------------
    public Connection getConnection(String username, String password) {
        throw Lang.noImplement();
    }

    public PrintWriter getLogWriter() throws SQLException {
        throw Lang.noImplement();
    }

    public int getLoginTimeout() throws SQLException {
        throw Lang.noImplement();
    }

    public void setLogWriter(PrintWriter out) throws SQLException {
        throw Lang.noImplement();
    }

    public void setLoginTimeout(int seconds) throws SQLException {
        throw Lang.noImplement();
    }

    public boolean isWrapperFor(Class iface) throws SQLException {
        throw Lang.noImplement();
    }

    public Object unwrap(Class iface) throws SQLException {
        throw Lang.noImplement();
    }
}

用来跑Nutz的TestCase, 在我的机器耗时5.2秒,与DBCP相当(5.3秒). 缺点: 1. 高并发时,可能建立过多的连接 2. 高并发时,部分连接可能没有被回收 3. 限制死了最多保存20个连接(当然,这个很好改) 4. XXX都没法配置

调用方法:

直接创建:

DataSource dataSource = new SimpleDataSource(“jdbc:h2:mem:~“,“org.h2.Driver”,“sa”,“sa”); //代码…..

//最后记得关闭一下,或者等GC的时候自行关闭. ((SimpleDataSource)dataSource).close();

NutIoc的json方式

dataSource : {
    type :"org.nutz.dao.impl.SimpleDataSource",
    events : {
        depose :"close"
    },
    args : ["jdbc:h2:mem:~","org.h2.Driver","sa","sa"]
}

哈哈,没啥技术含量,来拍我吧!!

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Published

2011-02-21 13:18:41

一个极其简陋的Datasource连接池实现

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