Spring中使用事務搭建轉賬環境 轉賬操作一個賬戶要減少資金操作一個賬戶要增加資金操作，如果在兩個操作間出現異常轉賬失敗 所以要使用事務

演示不使用事務出現異常情況

Dao層兩個方法lessMoney（）和moreMoney（）

package com.swift;

import org.springframework.jdbc.core.JdbcTemplate;

public class AccountDao {
    private JdbcTemplate jdbcTemplate;
    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    //少錢的方法
    public void lessMoney(String from,double number) {
        String sql="update account set money=money-? where username=?";
        jdbcTemplate.update(sql, number,from);
        
    }
    //多錢的方法
    public void moreMoney(String to,double number) {
        String sql="update account set money=money+? where username=?";
        jdbcTemplate.update(sql, number,to);
    }
}

Service層調用兩個方法

package com.swift;

public class AccountService {
    private AccountDao accountDao;
    public void setAccountDao(AccountDao accountDao) {
        this.accountDao = accountDao;
    }
    
    public void moneyTransfer(String from,String to,double number) {
        accountDao.lessMoney(from,number);
        int i=10/0;
        accountDao.moreMoney(to,number);
    }
}

但是兩個操作減與加之間，如果出現異常，則會導致轉賬錢已經轉了，但對方卻沒有到賬的bug，可能伺服器突然故障等引起

解決添加事務，出現異常進行回滾操作

下麵使用配置文件的方法進行事務管理

沒有改變的測試類

package com.swift;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

@WebServlet("/test")
public class ServletTest extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    public ServletTest() {
        super();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().append("Served at: ").append(request.getContextPath());
        
        //使用JdbcTemplat的queryForObject方法
        ApplicationContext context=new ClassPathXmlApplicationContext("c3p0.xml");
        AccountService accountService= (AccountService) context.getBean("accountService");
        accountService.moneyTransfer("傭兵組織", "高揚", 100000);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

}

使用配置文件進行事務處理步驟如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

    <!-- c3p0連接池得到dataSource -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/sw_database"></property>
        <property name="user" value="root"></property>
        <property name="password" value="root"></property>
    </bean>

    <!-- 第一步 配置事務管理器 -->
    <bean id="transactionManager"
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!-- 註入dataSource -->
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!-- 第二步 配置事務增強 -->
    <tx:advice id="txadvice" transaction-manager="transactionManager">
        <!-- 做事務操作 -->
        <tx:attributes>
            <!-- 事務操作的方法匹配規則 -->
            <tx:method name="money*" propagation="REQUIRED"/>
        </tx:attributes>
    </tx:advice>
    
    <!-- 第三步 配置切麵 -->
    <aop:config>
    <!-- 切入點 -->
    <aop:pointcut expression="execution(* com.swift.AccountService.*(..))" id="pointcut1"/>
    <!-- 切麵 -->
    <aop:advisor advice-ref="txadvice" pointcut-ref="pointcut1"/>
    </aop:config>

    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <bean id="accountDao" class="com.swift.AccountDao">
        <property name="jdbcTemplate" ref="jdbcTemplate"></property>
    </bean>

    <bean id="accountService" class="com.swift.AccountService">
        <property name="accountDao" ref="accountDao"></property>
    </bean>

</beans>

分三個步驟 管理 增強和切麵

雖然還是會有異常，但是資料庫中不會出錯，不會錢轉出了，卻沒有到賬

工具類Account

package com.swift;

public class Account {
    
    private int id;
    private String username;
    private String money;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getMoney() {
        return money;
    }
    public void setMoney(String money) {
        this.money = money;
    }
    public Account(int id, String username, String money) {
        this.id = id;
        this.username = username;
        this.money = money;
    }
    public Account() {
        super();
        // TODO Auto-generated constructor stub
    }
    @Override
    public String toString() {
        return "Account [id=" + id + ", username=" + username + ", money=" + money + "]";
    }
    
}