C3P0连接池、DBCP连接池

C3P0连接池：

配置文件：c3p0-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>

	<default-config>
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql:///mybase</property>
		<property name="user">root</property>
		<property name="password">xuyiqing</property>
		<property name="initialPoolSize">5</property>
		<property name="maxPoolSize">20</property>
	</default-config>

	<named-config name="yiqing">
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql:///mybase</property>
		<property name="user">root</property>
		<property name="password">xuyiqing</property>
	</named-config>


</c3p0-config>

　　测试：

数据准备：

CREATE DATABASE mybase;
USE mybase;
CREATE TABLE users(
uid INT PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(64),
upassword VARCHAR(64)
);
INSERT INTO users (username,upassword) VALUES("zhangsan","123"),("lisi","456"),("wangwu","789");
SELECT * FROM users;

自定义的JDBC工具类：

package demo;

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

public class JDBCUtils3 {
	public static String driver;
	public static String url;
	public static String username;
	public static String password;

	static {
		try {
			ClassLoader classLoader = JDBCUtils3.class.getClassLoader();
			InputStream is = classLoader.getResourceAsStream("db.properties");
			Properties props = new Properties();
			props.load(is);
			driver = props.getProperty("driver");
			url = props.getProperty("url");
			username = props.getProperty("username");
			password = props.getProperty("password");
		} catch (Exception ex) {
			ex.printStackTrace();
		}
	}

	public static Connection getConnection() {
		Connection conn = null;
		try {
			Class.forName(driver);
			conn = DriverManager.getConnection(url, username, password);
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return conn;
	}

	public static void release(Connection conn, PreparedStatement pstmt, ResultSet rs) {
		if (rs != null) {
			try {
				rs.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		if (pstmt != null) {
			try {
				pstmt.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		if (conn != null) {
			try {
				conn.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}

	}
}

　　配置文件：

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybase
username=root
password=xuyiqing

　　测试类：

package demo01;

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

import org.junit.Test;

import com.mchange.v2.c3p0.ComboPooledDataSource;

import demo.JDBCUtils3;

public class TestC3P0 {
	@Test
	public void testAddUser1() {
		Connection conn = null;
		PreparedStatement pstmt = null;
		ComboPooledDataSource dataSource = new ComboPooledDataSource();// 默认方式加载
		// ComboPooledDataSource dataSource = new ComboPooledDataSource("yiqing");
		try {
			conn = dataSource.getConnection();
			String sql = "insert into users values(null,?,?)";
			pstmt = conn.prepareStatement(sql);
			pstmt.setString(1, "张三");
			pstmt.setString(2, "123");
			int rows = pstmt.executeUpdate();
			if (rows > 0) {
				System.out.println("添加成功!");
			} else {
				System.out.println("添加失败!");
			}
		} catch (Exception e) {
			throw new RuntimeException(e);
		} finally {
			JDBCUtils3.release(conn, pstmt, null);
		}
	}
}

　　成功！

可以将C3P0连接池抽取出工具类：

package demo01;

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

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class C3P0Utils {
    private static ComboPooledDataSource dataSource = new ComboPooledDataSource();

    public static DataSource getDataSource() {
        return dataSource;
    }

    public static Connection getConnection() {
        try {
            return dataSource.getConnection();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}

测试：

package demo01;

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

import org.junit.Test;

import demo.JDBCUtils3;

public class TestC3P0 {
    @Test
    public void testAddUser1() {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = C3P0Utils.getConnection();
            String sql = "insert into users values(null,?,?)";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, "李四");
            pstmt.setString(2, "123123");
            int rows = pstmt.executeUpdate();
            if (rows > 0) {
                System.out.println("添加成功!");
            } else {
                System.out.println("添加失败!");
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtils3.release(conn, pstmt, null);
        }
    }
}

成功！

DBCP连接池：

自定义DBCP工具类：

package DBCP;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.commons.dbcp.BasicDataSourceFactory;

public class DBCPUtils {
    private static DataSource dataSource;
    static {
        try {
            // 1.加载找properties文件输入流
            InputStream is = DBCPUtils.class.getClassLoader().getResourceAsStream("db.properties");
            // 2.加载输入流
            Properties props = new Properties();
            props.load(is);
            // 3.创建数据源
            dataSource = BasicDataSourceFactory.createDataSource(props);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static DataSource getDataSource() {
        return dataSource;
    }

    public static Connection getConnection() {
        try {
            return dataSource.getConnection();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}

测试：

package DBCP;
import java.sql.Connection;
import java.sql.PreparedStatement;

import org.junit.Test;

public class TestDBCP {

    @Test
    public void testUpdateUserById(){
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = DBCPUtils.getConnection();
            String sql ="update users set upassword=? where uid=?";
            pstmt= conn.prepareStatement(sql);
            pstmt.setString(1, "456789");
            pstmt.setInt(2, 1);
            int rows = pstmt.executeUpdate();
            if(rows>0){
                System.out.println("更新成功!");
            }else{
                System.out.println("更新失败!");
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}