53.c3p0鏈接數據庫=======》控制事務

時間 2019-12-11

標籤 53.c3p0 鏈接數據庫控制事務欄目 C&C++ 简体版

原文原文鏈接

1.效果java

2.準備mysql

2.1導入須要的jarsql

2.2 導入c3p0工具類數據庫

c3p0工具類代碼apache

package cn.ma.utils;工具

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

import javax.sql.DataSource;.net

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

public class C3P0utils {
   /**
   * 1.建立一個鏈接池對象
   */
static DataSource ds = new ComboPooledDataSource();

   public static DataSource getDataSource(){
       return ds;
   }

   /**
   * 2.從池中得到一個鏈接
   * @Title: getConnection
   * @Description:
   * @return
   * @throws SQLException
   * @return Connection
   * @throws
   */
   public static Connection getConnection() throws SQLException{
       return ds.getConnection();
   }

   /**
   * 3.釋放資源
   * @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();//放心的關。是否關閉取決鏈接是怎麼來的
           } catch (SQLException e) {
               throw new RuntimeException(e);
           }
           conn = null;
       }

   }對象

}

2.3 c3p0 鏈接數據庫的xml文件

代碼

<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 數據庫表結構

3.測試類

代碼：

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.使用無參對象，才能控制事務 try { conn = C3P0utils.getConnection();//2.手動獲得鏈接 conn.setAutoCommit(false);//3.手動提交事務 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.這裏必須將鏈接對象傳遞 int i=1/0; //5.製造異常 qr.update(conn,sql2); conn.commit();//6.沒有異常提交事務 } catch (SQLException e) { e.printStackTrace(); try { conn.rollback();//7.有異常回滾 } catch (SQLException e1) { e1.printStackTrace(); } }finally { if(conn !=null){ try { conn.close();//8.關閉鏈接 } catch (SQLException e) { e.printStackTrace(); } } } } }