掌握c3p0

2. 路径

1. c3p0 介绍

2. c3p0 的使⽤ ( 硬编码 )

3. c3p0 的使⽤ ( 配置⽂件 )

4. 编写 C3P0Util ⼯具类

3. 讲解

3.1 c3p0 介绍 C3P0 开源免费的连接池！⽬前使⽤它的开源项⽬有：

Spring 、 Hibernate 等。使⽤第三⽅⼯具需要导⼊ jar 包，

c3p0 使⽤时还需要添加配置⽂件 c3p0-config.xml.

使⽤ C3P0 需要添加 c3p0-0.9.1.2.jar

3.2c3p0 的使⽤

3.2.1 通过硬编码来编写【了解】

步骤

1. 拷⻉ jar

2. 创建 C3P0 连接池对象

3. 从 C3P0 连接池对象⾥⾯获得 connection

导入jar包

<!-- https://mvnrepository.com/artifact/c3p0/c3p0 -->
<dependency>
    <groupId>c3p0</groupId>
    <artifactId>c3p0</artifactId>
    <version>0.9.1.2</version>
</dependency>

创建工具类

import com.mchange.v2.c3p0.ComboPooledDataSource;

import javax.sql.DataSource;

public class C3P0Util {
    /**
     * 包名:com.sunlw.utils
     *
     * @author sunlw
     * ⽇期2020-07-06 11:43
     * 这个⼯具类就负责，提供C3P0连接池对象
     */
    private static DataSource dataSource;

    static {
        dataSource = new ComboPooledDataSource();
    }

    /**
     * 获取连接池
     *
     * @return
     */
    public static DataSource getDataSource() {
        return dataSource;
    }
}

resources下创建c3p0-config.xml

<c3p0-config>
    <default-config>
        <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/2207b</property>
        <property name="user">root</property>
        <property name="password">123456</property>
        <property name="initialPoolSize">5</property>
    </default-config>
</c3p0-config>

代码运行

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.junit.Test;

import javax.sql.DataSource;
import java.beans.PropertyVetoException;
import java.sql.Connection;
import java.sql.SQLException;

public class c3p0Date {
    @Test
    public void c3p0show() throws PropertyVetoException, SQLException {
        ComboPooledDataSource cpds = new ComboPooledDataSource();
        cpds.setDriverClass("com.mysql.cj.jdbc.Driver");
        cpds.setJdbcUrl("jdbc:mysql://localhost:3306/2207b");
        cpds.setUser("root");
        cpds.setPassword("123456");
        Connection connection = cpds.getConnection();
        System.out.println(connection);
    }
    @Test
    public void c3p0show2() throws SQLException {
        DataSource dataSource = C3P0Util.getDataSource();
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
    }
}