同过增强Connection类[重写了close的方法]实现的从连接池取出连接并放回连接的简单的实现流程(一)

package tk.dong.connection.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.sql.Array;
import java.sql.Blob;
import java.sql.CallableStatement;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.NClob;
import java.sql.PreparedStatement;
import java.sql.SQLClientInfoException;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.sql.SQLWarning;
import java.sql.SQLXML;
import java.sql.Savepoint;
import java.sql.Statement;
import java.sql.Struct;
import java.util.LinkedList;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.Executor;
import java.util.logging.Logger;

import javax.sql.DataSource;

//这是同过增强Connection类[重写了close的方法]实现的从连接池取出连接并放回连接
public class JdbcPool implements DataSource {

	// 创建连接池,用的是LinkList,
	private static LinkedList connections = new LinkedList();

	// 通过静态初始化块创建,当程序进行初始化的时候就会触发

	static {
		// 将连接数据库的配置文件读入到流中
		InputStream inStream = JdbcPool.class.getClassLoader().getResourceAsStream(
				"jdbc.properties");
		Properties properties = new Properties();
		try {
			properties.load(inStream);

			// 获取连接数据库的驱动(根据property属性文件中的属性获取驱动)
			Class.forName(properties.getProperty("driverClassName"));
			for (int i = 0; i < 10; i++) {
				// 获取conn连接连接对象
				Connection conn = DriverManager.getConnection(
						properties.getProperty("url"),
						properties.getProperty("user"),
						properties.getProperty("pass"));

				// 这是在装入连接池的时候进行的操作处理,将connection中的close进行改写
				MyConnection myConnection = new MyConnection(conn, connections);

				// 将处理后的连接对象存入连接池
				connections.add(myConnection);
				System.out.println("连接池已经加入了::::::::::" + connections.size()
						+ "::::::::::个链接对象");
			}

		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

	// 这两个是从连接池中获取连接的方法
	@Override
	public Connection getConnection() throws SQLException {

		//生命连接对象
		Connection conn=null;
		if(connections.size()>





0){
			//取出链表中的第一个对象赋值给临时的连接对象
			conn=connections.removeFirst();
			System.out.println("又一个连接对象被拿走:::::::连接池还有"+connections.size()+"个连接对象");
		}
		return conn;
	}

	@Override
	public Connection getConnection(String username, String password)
			throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public PrintWriter getLogWriter() throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void setLogWriter(PrintWriter out) throws SQLException {
		// TODO Auto-generated method stub

	}

	@Override
	public void setLoginTimeout(int seconds) throws SQLException {
		// TODO Auto-generated method stub

	}

	@Override
	public int getLoginTimeout() throws SQLException {
		// TODO Auto-generated method stub
		return 0;
	}

	@Override
	public Logger getParentLogger() throws SQLFeatureNotSupportedException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public  T unwrap(Class iface) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public boolean isWrapperFor(Class< > iface) throws SQLException {
		// TODO Auto-generated method stub
		return false;
	}

}

// 增强的Connection 连接对类
// 装饰器模式
// 1.首先看需要被增强对象继承了什么接口或父类，编写一个类也去继承这些接口或父类。
class MyConnection implements Connection {
	// 2.在类中定义一个变量，变量类型即需增强对象的类型。
	// 用来接收连接池
	private LinkedList connections;
	// 用来接收连接对象
	private Connection conn;

	// 构造器为
	public MyConnection(Connection conn, LinkedList connections) {
		this.conn = conn;
		this.connections = connections;
	}

	// 我只用到这个方法所以我只写这个方法
	@Override
	public void close() throws SQLException {
		// 将不用的连接再次放入连接池
		connections.add(conn);
		System.ou