C3P0连接池

使用mysql的c3p0

除了c3p0.jar还要使用

Mchange Commons Java这里面的jar

 我们应该知道mchange-commons包是c3p0数据库连接池的辅助包，如果没有这个包系统启动时会报classnotfoundexception，这是更新c3p0-0.9.2版本后分离出来的包，0.9.1的时候还是只是一个包，但是我加了mchange-commons包还是报包错，那就是辅助包与c3p0包不兼容了
 

写c3p0-config.properties文件

测试c3p0类

输出：

最后补充一个之前写DBCP连接池的错误

就是第二个使用property配置属性的时候

里面配置属性命名问题都要小写，不然链接会报错：

Caused by: java.sql.SQLException: Access denied for user ''@'localhost' (using password: YES)

报错截图

 改正后正确运行截图

代码：

C3P0Demp

package com.yanqun.util;

import com.mchange.v2.c3p0.ComboPooledDataSource;

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

public class C3P0Demp {

    public  static DataSource getDataSourceWithC3P0() throws PropertyVetoException {
        ComboPooledDataSource c3p0=new ComboPooledDataSource();
        c3p0.setDriverClass("com.mysql.cj.jdbc.Driver");
        c3p0.setJdbcUrl("jdbc:mysql://localhost:3306/goods");
        c3p0.setUser("root");
        c3p0.setPassword("123456");
        return c3p0;
    }

    public  static DataSource getDataSourceWithC3P0ByXml() throws PropertyVetoException {
        ComboPooledDataSource c3p0=new ComboPooledDataSource("yanqun");
        return c3p0;
    }

    public static void main(String[] args) throws PropertyVetoException, SQLException {
        System.out.println(getDataSourceWithC3P0().getConnection());
        System.out.println("========================================");
        System.out.println(getDataSourceWithC3P0ByXml().getConnection());
    }
}

DataSourceUtil

package com.yanqun.util;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.apache.commons.dbcp.BasicDataSource;
import org.apache.commons.dbcp.BasicDataSourceFactory;

import javax.sql.DataSource;
import java.beans.PropertyVetoException;
import java.io.InputStream;
import java.util.Properties;

public class DataSourceUtil {

    //硬编码
    public static DataSource getDataSourceWithDBCP(){
        BasicDataSource dbcp=new BasicDataSource();
        dbcp.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dbcp.setUrl("jdbc:mysql://localhost:3306/goods");
        dbcp.setUsername("root");
        dbcp.setPassword("123456");
        dbcp.setInitialSize(20);
        dbcp.setMaxActive(10);
        return dbcp;
    }

    public static DataSource getDataSourceWithDBCPByProperties() throws Exception {
        DataSource dbcp=null;
        Properties props=new Properties();
        //将字符串变成一个输入流
        InputStream input = new DBCPDemo().getClass().getClassLoader().getResourceAsStream("dbcpconfig.properties");

        //因为load需要一个流的形式，而我们properties的path是一个字符串
        //所以需要将一个字符串类型的数据转成流的形式
        props.load(input);

        dbcp= BasicDataSourceFactory.createDataSource(props);

        return dbcp;
    }


    //c3p0数据连接池
    public  static DataSource getDataSourceWithC3P0() throws PropertyVetoException {
        ComboPooledDataSource c3p0=new ComboPooledDataSource();
        c3p0.setDriverClass("com.mysql.cj.jdbc.Driver");
        c3p0.setJdbcUrl("jdbc:mysql://localhost:3306/goods");
        c3p0.setUser("root");
        c3p0.setPassword("123456");
        return c3p0;
    }

    public  static DataSource getDataSourceWithC3P0ByXml() throws PropertyVetoException {
        ComboPooledDataSource c3p0=new ComboPooledDataSource("yanqun");
        return c3p0;
    }
}

DBCPDemo

package com.yanqun.util;


import org.apache.commons.dbcp.BasicDataSource;
import org.apache.commons.dbcp.BasicDataSourceFactory;

import javax.sql.DataSource;
import java.io.InputStream;
import java.util.Properties;

public class DBCPDemo {


    //硬编码
    public static DataSource getDataSourceWithDBCP(){

        /*
        private static final String URL = "jdbc:mysql://localhost:3306/goods";
    private static final String USERNAME = "root";
    private  static final String PWD = "123456";
//通过jdbc存储二进制类型
//    设置Blob类型：
    public static void blobDemo() {//增删改
        PreparedStatement pstmt = null;
        Connection connection = null;
        try {
//            a.导入驱动，加载具体的驱动类
            Class.forName("com.mysql.cj.jdbc.Driver");

         */
        BasicDataSource dbcp=new BasicDataSource();
        dbcp.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dbcp.setUrl("jdbc:mysql://localhost:3306/goods");
        dbcp.setUsername("root");
        dbcp.setPassword("123456");
        dbcp.setInitialSize(20);
        dbcp.setMaxActive(10);
        return dbcp;
    }

    public static DataSource getDataSourceWithDBCPByProperties() throws Exception {
        DataSource dbcp=null;
        Properties props=new Properties();
        //将字符串变成一个输入流
        InputStream input = new DBCPDemo().getClass().getClassLoader().getResourceAsStream("dbcpconfig.properties");

        //因为load需要一个流的形式，而我们properties的path是一个字符串
        //所以需要将一个字符串类型的数据转成流的形式
        props.load(input);

        dbcp=BasicDataSourceFactory.createDataSource(props);

        return dbcp;
    }

    public static void main(String[] args) throws Exception {

//        System.out.println(DataSourceUtil.getDataSourceWithDBCPByProperties().getConnection());
        System.out.println(getDataSourceWithDBCPByProperties().getConnection());
    }
}

c3p0-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <default-config>
        <property name="user">root</property>
        <property name="password">123456</property>
        <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/goods</property>
        <property name="checkoutTimeout">30000</property>
    </default-config>
    <name-config name="yanqun">
        <property name="user">root</property>
        <property name="password">123456</property>
        <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/goods</property>
        <property name="checkoutTimeout">20000</property>

    </name-config>

</c3p0-config>

dbcpconfig.properties

driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/goods
username=root
password=123456
initialSize=10