JDBC连接池一 自定义连接池

package com.mozq.jdbc;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

/**
 * 	使用Properties类，从配置文件获取配置信息。实现JDBCUtils工具类
 * 
 * @author jie
 *
 */
public class JDBCUtils_V2 {
	// 1.准备配置信息
	public static String dirverClass;
	public static String url;
	public static String user;
	public static String password;
	
	static {
		ClassLoader classLoader = JDBCUtils_V2.class.getClassLoader();
		InputStream inStream = classLoader.getResourceAsStream("db.properties");
		Properties properties = new Properties();
		try {
			properties.load(inStream);
			dirverClass = properties.getProperty("dirverClass");
			url = properties.getProperty("url");
			user = properties.getProperty("user");
			password = properties.getProperty("password");
			
			Class.forName(dirverClass);
		} catch (IOException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}
	/**
	 * 获取连接
	 * 
	 * @throws ClassNotFoundException
	 */
	public static Connection getConnection() {
		// 2.加载驱动，获得链接
		Connection connection = null;
		try {
			connection = DriverManager.getConnection(url, user, password);
		}catch (SQLException e) {
			e.printStackTrace();
		}
		return connection;
	}
	
	/**
	 * 释放资源，注意资源的释放顺序
	 */
	public static void release(Connection conn, PreparedStatement pstmt, ResultSet rs) {
		if(rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if(pstmt != null) {
			try {
				pstmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if(conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
}

　　

package com.mozq.jdbc;

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.NClob;
import java.sql.PreparedStatement;
import java.sql.SQLClientInfoException;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.SQLXML;
import java.sql.Savepoint;
import java.sql.Statement;
import java.sql.Struct;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.Executor;

/**
 * 装饰者设计模式：需要增强接口实现类的接口方法。创建实现接口的一个装饰类。
 * 	实例：增强Connection实现类的close()方法
 * 	装饰类的设计步骤：
 * 1.实现接口
 * 2.提供含有接口类型参数的构造器
 * 3.提供接口类型成员变量
 * 4.增强需要的方法
 * 5.调用接口类型变量，实现不需要增强的方法
 * @author jie
 *
 */
public class MyConnection implements Connection {
	//1.定义接口变量
	private Connection conn;
	
	private List<Connection> pool;
	
	//2.定义接口变量为参数的构造器
	public MyConnection(Connection conn , List<Connection> pool){
		this.conn = conn;
		this.pool = pool;
	}
	
	//3.增强需要的方法
	@Override
	public void close() throws SQLException {
		pool.add(conn);
		System.out.println("将连接放回连接池");
	}
	
	//4.调用接口变量，实现不需要增强的方法
	@Override
	public PreparedStatement prepareStatement(String sql) throws SQLException {
		return conn.prepareStatement(sql);
	}

	@Override
	public <T> T unwrap(Class<T> 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;
	}

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

	@Override
	public CallableStatement prepareCall(String sql) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public String nativeSQL(String sql) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void setAutoCommit(boolean autoCommit) throws SQLException {
		// TODO Auto-generated method stub

	}

	@Override
	public boolean getAutoCommit() throws SQLException {
		// TODO Auto-generated method stub
		return false;
	}

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

	}

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

	}

	@Override
	public boolean isClosed() throws SQLException {
		// TODO Auto-generated method stub
		return false;
	}

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

	@Override
	public void setReadOnly(boolean readOnly) throws SQLException {
		// TODO Auto-generated method stub

	}

	@Override
	public boolean isReadOnly() throws SQLException {
		// TODO Auto-generated method stub
		return false;
	}

	@Override
	public void setCatalog(String catalog) throws SQLException {
		// TODO Auto-generated method stub

	}

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

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

	}

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

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

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

	}

	@Override
	public Statement createStatement(int resultSetType, int resultSetConcurrency) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency)
			throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public Map<String, Class<?>> getTypeMap() throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void setTypeMap(Map<String, Class<?>> map) throws SQLException {
		// TODO Auto-generated method stub

	}

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

	}

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

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

	@Override
	public Savepoint setSavepoint(String name) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void rollback(Savepoint savepoint) throws SQLException {
		// TODO Auto-generated method stub

	}

	@Override
	public void releaseSavepoint(Savepoint savepoint) throws SQLException {
		// TODO Auto-generated method stub

	}

	@Override
	public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability)
			throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency,
			int resultSetHoldability) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency,
			int resultSetHoldability) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public PreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

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

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

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

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

	@Override
	public boolean isValid(int timeout) throws SQLException {
		// TODO Auto-generated method stub
		return false;
	}

	@Override
	public void setClientInfo(String name, String value) throws SQLClientInfoException {
		// TODO Auto-generated method stub

	}

	@Override
	public void setClientInfo(Properties properties) throws SQLClientInfoException {
		// TODO Auto-generated method stub

	}

	@Override
	public String getClientInfo(String name) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

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

	@Override
	public Array createArrayOf(String typeName, Object[] elements) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public Struct createStruct(String typeName, Object[] attributes) throws SQLException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void setSchema(String schema) throws SQLException {
		// TODO Auto-generated method stub

	}

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

	@Override
	public void abort(Executor executor) throws SQLException {
		// TODO Auto-generated method stub

	}

	@Override
	public void setNetworkTimeout(Executor executor, int milliseconds) throws SQLException {
		// TODO Auto-generated method stub

	}

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

}

　　

package com.mozq.jdbc;

import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.LinkedList;
import java.util.logging.Logger;

import javax.sql.DataSource;

public class MyDataSourceMyConn implements DataSource {
	// 准备一个池子保存连接
	private static LinkedList<Connection> pool = new LinkedList<Connection>();

	// 从配置文件加载参数
	private static int init = 5;

	static {
		// 初始化池子
		for (int i = 0; i < init; ++i) {
			Connection connection = JDBCUtils_V2.getConnection();
			
			//增强Connection实现类
			MyConnection myConnection = new MyConnection(connection, pool);
			pool.add(myConnection);
		}
	}

	/**
	 * 覆盖获取连接的方法
	 */
	@Override
	public Connection getConnection() throws SQLException {
		// 获取连接前先判断
		if (pool.size() == 0) {
			//如果没有连接，创建一些
			for (int i = 0; i < init; ++i) {
				Connection connection = JDBCUtils_V2.getConnection();
				
				//增强Connection实现类
				MyConnection myConnection = new MyConnection(connection, pool);
				pool.add(myConnection);
			}
		}
		//从池子里获取连接返回
		return pool.remove();
	}

	@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> T unwrap(Class<T> 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;
	}

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

}

　　

package com.mozq.jdbc.test;

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

import javax.sql.DataSource;

import org.junit.Test;

import com.mozq.jdbc.JDBCUtils_V2;
import com.mozq.jdbc.MyDataSourceMyConn;

public class MyDataSourceMyConnTest {
	@Test
	public void insert() {
		// 准备参数
		String user = "刘备";
		String password = "123";
		
		Connection conn = null;
		PreparedStatement pstmt = null;
		DataSource myDataSource = new MyDataSourceMyConn();
		try {
			// 获取链接
			conn = myDataSource.getConnection();
			// 获取语句执行对象
			String sql = "insert into t_user (name, password) values(?, ?)";
			pstmt = conn.prepareStatement(sql);
			pstmt.setString(1, user);
			pstmt.setString(2, password);
			// 结果处理
			int row = pstmt.executeUpdate();
			if (row > 0) {
				System.out.println("插入用户成功");
			} else {
				System.out.println("插入用户失败");
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			JDBCUtils_V2.release(conn, pstmt, null);;
		}
	}
}