53.c3p0链接数据库=======》控制事务

时间 2019-12-11

标签 53.c3p0 链接数据库控制事务栏目 C&C++ 繁體版

原文原文链接

1.效果java

2.准备mysql

2.1导入须要的jarsql

2.2 导入c3p0工具类数据库

c3p0工具类代码apache

package cn.ma.utils;工具

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;测试

import javax.sql.DataSource;.net

import com.mchange.v2.c3p0.ComboPooledDataSource;xml

public class C3P0utils {
   /**
   * 1.建立一个链接池对象
   */
static DataSource ds = new ComboPooledDataSource();

   public static DataSource getDataSource(){
       return ds;
   }

   /**
   * 2.从池中得到一个链接
   * @Title: getConnection
   * @Description:
   * @return
   * @throws SQLException
   * @return Connection
   * @throws
   */
   public static Connection getConnection() throws SQLException{
       return ds.getConnection();
   }

   /**
   * 3.释放资源
   * @Title: closeAll
   * @Description:
   * @param rs
   * @param stmt
   * @param conn
   * @return void
   * @throws
   */
   public static void closeAll(ResultSet rs,Statement stmt,Connection conn){
       if(rs!=null){
           try {
               rs.close();
           } catch (SQLException e) {
               throw new RuntimeException(e);
           }
           rs = null;
       }
       if(stmt!=null){
           try {
               stmt.close();
           } catch (SQLException e) {
               throw new RuntimeException(e);
           }
           stmt = null;
       }

       if(conn!=null){
           try {
               conn.close();//放心的关。是否关闭取决链接是怎么来的
           } catch (SQLException e) {
               throw new RuntimeException(e);
           }
           conn = null;
       }

   }对象

}

2.3 c3p0 链接数据库的xml文件

代码

<c3p0-config>
<default-config>

<property name="driverClass">com.mysql.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:mysql://localhost:3306/day19</property>
<property name="user">root</property>
<property name="password">root</property>
<property name="initialPoolSize">10</property>

</default-config>

</c3p0-config>

2.4 数据库表结构

3.测试类

代码：

package cn.ma.transitionManager;

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

import org.apache.commons.dbutils.QueryRunner;
import org.junit.Test;

import cn.ma.utils.C3P0utils;

public class C3P0transitionManager { @Test public void TestC3P0transitionManager(){ Connection conn=null; QueryRunner qr = new QueryRunner();//1.使用无参对象，才能控制事务 try { conn = C3P0utils.getConnection();//2.手动获得链接 conn.setAutoCommit(false);//3.手动提交事务 String sql="update t_transitionManager set money=money-100 where accountnumber='999'"; String sql2="update t_transitionManager set money=money+100 where accountnumber='666'"; qr.update(conn,sql);//4.这里必须将链接对象传递 int i=1/0; //5.制造异常 qr.update(conn,sql2); conn.commit();//6.没有异常提交事务 } catch (SQLException e) { e.printStackTrace(); try { conn.rollback();//7.有异常回滚 } catch (SQLException e1) { e1.printStackTrace(); } }finally { if(conn !=null){ try { conn.close();//8.关闭链接 } catch (SQLException e) { e.printStackTrace(); } } } } }