Spring初学之spring的事务管理注解

spring的事务管理，本文的例子是：比如你需要网购一本书，卖书的那一方有库存量以及书的价格，你有账户余额。回想我们在编程中要实现买书这样的功能，由于你的账户表和书的库存量表肯定不是同一张数据库表，所以必定会有一个先后，要么先将账户余额扣除书的价格，紧接着将书的库存量减一，要么反过来。那么问题来了，假如我们先将你的账户余额减掉，然后发现书的库存不足，这时怎么办呢，这就需要事务了，当我们发现书的库存不足时就要回滚事务，将你的余额返回去。只要配置了事务，发生了异常，就回滚。这就是事务的回滚。注：新人理解，如有错误，望指正，谢谢。

 配置文件applicationContext.xml：

<?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:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">

    <!-- 导入资源文件 -->
    <context:property-placeholder location="classpath:jdbc.properties"/>
    
    <!-- 配置c3p0数据源 -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="user" value="${user}"></property>
        <property name="password" value="${password}"></property>
        <property name="driverClass" value="${driverClass}"></property>
        <property name="jdbcUrl" value="${jdbcUrl}"></property>
        
        <property name="initialPoolSize" value="${initPoolSize}"></property>
        <property name="maxPoolSize" value="${maxPoolSize}"></property>
    </bean>
    
    <!-- 配置自动扫描的包 -->
    <context:component-scan base-package="spring"></context:component-scan>
    
    <!-- 配置spring 的JdbcTemplate -->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!-- 配置事务管理器 -->
    <bean id="transactionManager" 
    class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <!-- 启用事务注解 -->
    <tx:annotation-driven transaction-manager="transactionManager"/>
    
    
</beans>

 配置文件jdbc.propertices：

user=root
password=123
driverClass=com.mysql.jdbc.Driver
jdbcUrl=jdbc:mysql:///spring?encoding=UFT-8
initPoolSize=5
maxPoolSize=20

BookShopDao.java：

package spring.tx;

public interface BookShopDao {

    public int findBookPriceByIsbn(String isbn);
    public void updataBookStock(String isbn);
    public void updataUserAccount(String username,int price);
}

BookShopDaoImp.java：

package spring.tx;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

@Repository("bookShopDao")
public class BookShopDaoImp implements BookShopDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public int findBookPriceByIsbn(String isbn) {
        String sql = "select price from book where isbn=?";
        return jdbcTemplate.queryForObject(sql, Integer.class, isbn);
    }

    @Override
    public void updataBookStock(String isbn) {
        // 检查书的库存是否不够
        String sql1 = "select stock from book_stock where isbn=?";
        if (jdbcTemplate.queryForObject(sql1, Integer.class, isbn) <= 0) {
            throw new BookStockException("库存不足");
        }
        String sql = "update book_stock  set stock=stock-1 where isbn=?";
        jdbcTemplate.update(sql, isbn);
    }

    @Override
    public void updataUserAccount(String username, int price) {
        // 检查余额是否足够
        String sql1 = "select balance from account where username=?";
        if (jdbcTemplate.queryForObject(sql1, Integer.class, username) < price) {
            throw new UserAccountException("余额不足");
        }
        String sql = "update account set balance = balance - ? where username=?";
        jdbcTemplate.update(sql, price, username);
    }

}

BookShopService.java：

package spring.tx;

public interface BookShopService {
    public void purchase(String username,String isbn);
}

BookShopServiceImpl.java：

package spring.tx;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

@Repository("bookShopDao")
public class BookShopDaoImp implements BookShopDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public int findBookPriceByIsbn(String isbn) {
        String sql = "select price from book where isbn=?";
        return jdbcTemplate.queryForObject(sql, Integer.class, isbn);
    }

    @Override
    public void updataBookStock(String isbn) {
        // 检查书的库存是否不够
        String sql1 = "select stock from book_stock where isbn=?";
        if (jdbcTemplate.queryForObject(sql1, Integer.class, isbn) <= 0) {
            throw new BookStockException("库存不足");
        }
        String sql = "update book_stock  set stock=stock-1 where isbn=?";
        jdbcTemplate.update(sql, isbn);
    }

    @Override
    public void updataUserAccount(String username, int price) {
        // 检查余额是否足够
        String sql1 = "select balance from account where username=?";
        if (jdbcTemplate.queryForObject(sql1, Integer.class, username) < price) {
            throw new UserAccountException("余额不足");
        }
        String sql = "update account set balance = balance - ? where username=?";
        jdbcTemplate.update(sql, price, username);
    }

}

Cashier.java：

package spring.tx;

import java.util.List;

public interface Cashier {
    public void checkout(String username,List<String> isbns); 
}

CashierImpl.java：

package spring.tx;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

@Service("cashier")
public class CashierImpl implements Cashier {

    @Autowired
    private BookShopService bookShopService;
    
    
    @Transactional
    @Override
    public void checkout(String username, List<String> isbns) {
        for (int i = 0; i < isbns.size(); i++) {
            bookShopService.purchase(username, isbns.get(i));
        }
    }

}

定义两个异常类：

package spring.tx;

public class BookStockException extends RuntimeException{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    public BookStockException() {
        super();
        // TODO Auto-generated constructor stub
    }

    public BookStockException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
        // TODO Auto-generated constructor stub
    }

    public BookStockException(String message, Throwable cause) {
        super(message, cause);
        // TODO Auto-generated constructor stub
    }

    public BookStockException(String message) {
        super(message);
        // TODO Auto-generated constructor stub
    }

    public BookStockException(Throwable cause) {
        super(cause);
        // TODO Auto-generated constructor stub
    }

    
}

package spring.tx;


public class UrAccountExceptionse extends RuntimeException {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    public UserAccountException() {
        super();
        // TODO Auto-generated constructor stub
    }

    public UserAccountException(String message, Throwable cause, boolean enableSuppression,
            boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
        // TODO Auto-generated constructor stub
    }

    public UserAccountException(String message, Throwable cause) {
        super(message, cause);
        // TODO Auto-generated constructor stub
    }

    public UserAccountException(String message) {
        super(message);
        // TODO Auto-generated constructor stub
    }

    public UserAccountException(Throwable cause) {
        super(cause);
        // TODO Auto-generated constructor stub
    }

}

测试方法：

package spring.tx.test;

import java.util.ArrayList;
import java.util.List;

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

import spring.tx.BookShopDao;
import spring.tx.BookShopService;
import spring.tx.Cashier;

public class SpringTransactionTest {

    private ApplicationContext ctx=null;
    private BookShopDao bookShopDao;
    private BookShopService bookShopService;
    private Cashier cashier;
    {
        ctx=new ClassPathXmlApplicationContext("applicationContext.xml");
        bookShopDao =(BookShopDao) ctx.getBean("bookShopDao");
        bookShopService=(BookShopService) ctx.getBean("bookShopService");
        cashier =(Cashier) ctx.getBean("cashier");
    }
    
    @Test
    public void testTransactionPropagation(){
        List<String > isbns=new ArrayList<String>();
        isbns.add("1001");
        isbns.add("1002");
        cashier.checkout("aaa", isbns);
    }
    
    @Test
    public  void testBookShopService() {
         bookShopService.purchase("aaa", "1001");
    }
    
    @Test
    public void testupdataBookStock(){
        bookShopDao.updataBookStock("1001");
    }
    
    @Test
    public void testUpdataUserAccount(){
        bookShopDao.updataUserAccount("aaa", 200);
    }
    
    @Test
    public void testBookShopDao(){
        int price=bookShopDao.findBookPriceByIsbn("1001");
        System.out.println(price);
    
    }
}