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);;

		}

	}

}

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