• Spring_事务-注解代码


    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: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.xsd
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">

    <context:component-scan base-package="com.atguigu.spring"></context:component-scan>

    <!-- 导入资源文件 -->
    <context:property-placeholder location="classpath:db.properties"/>

    <!-- 配置 C3P0 数据源 -->
    <bean id="dataSource"
    class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <property name="user" value="${jdbc.user}"></property>
    <property name="password" value="${jdbc.password}"></property>
    <property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
    <property name="driverClass" value="${jdbc.driverClass}"></property>

    <property name="initialPoolSize" value="${jdbc.initPoolSize}"></property>
    <property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property>
    </bean>

    <!-- 配置 Spirng 的 JdbcTemplate -->
    <bean id="jdbcTemplate"
    class="org.springframework.jdbc.core.JdbcTemplate">
    <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!-- 配置 NamedParameterJdbcTemplate, 该对象可以使用具名参数, 其没有无参数的构造器, 所以必须为其构造器指定参数 -->
    <bean id="namedParameterJdbcTemplate"
    class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
    <constructor-arg ref="dataSource"></constructor-arg>
    </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>

    BookShopDao.JAVA

    package com.atguigu.spring.tx;

    public interface BookShopDao {

    //根据书号获取书的单价
    public int findBookPriceByIsbn(String isbn);

    //更新数的库存. 使书号对应的库存 - 1
    public void updateBookStock(String isbn);

    //更新用户的账户余额: 使 username 的 balance - price
    public void updateUserAccount(String username, int price);
    }

    BookShopDaoImpl.JAVA

    package com.atguigu.spring.tx;

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

    @Repository("bookShopDao")
    public class BookShopDaoImpl 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 updateBookStock(String isbn) {
    //检查书的库存是否足够, 若不够, 则抛出异常
    String sql2 = "SELECT stock FROM book_stock WHERE isbn = ?";
    int stock = jdbcTemplate.queryForObject(sql2, Integer.class, isbn);
    if(stock == 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 updateUserAccount(String username, int price) {
    //验证余额是否足够, 若不足, 则抛出异常
    String sql2 = "SELECT balance FROM account WHERE username = ?";
    int balance = jdbcTemplate.queryForObject(sql2, Integer.class, username);
    if(balance < 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 com.atguigu.spring.tx;

    public interface BookShopService {

    public void purchase(String username, String isbn);

    }

    BookShopServiceImpl.JAVA

    package com.atguigu.spring.tx;

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

    @Service("bookShopService")
    public class BookShopServiceImpl implements BookShopService {

    @Autowired
    private BookShopDao bookShopDao;

    //添加事务注解
    //1.使用 propagation 指定事务的传播行为, 即当前的事务方法被另外一个事务方法调用时
    //如何使用事务, 默认取值为 REQUIRED, 即使用调用方法的事务
    //REQUIRES_NEW: 事务自己的事务, 调用的事务方法的事务被挂起.
    //2.使用 isolation 指定事务的隔离级别, 最常用的取值为 READ_COMMITTED
    //3.默认情况下 Spring 的声明式事务对所有的运行时异常进行回滚. 也可以通过对应的
    //属性进行设置. 通常情况下去默认值即可.
    //4.使用 readOnly 指定事务是否为只读. 表示这个事务只读取数据但不更新数据,
    //这样可以帮助数据库引擎优化事务. 若真的事一个只读取数据库值的方法, 应设置 readOnly=true
    //5.使用 timeout 指定强制回滚之前事务可以占用的时间.
    // @Transactional(propagation=Propagation.REQUIRES_NEW,
    // isolation=Isolation.READ_COMMITTED,
    // noRollbackFor={UserAccountException.class})
    @Transactional(propagation=Propagation.REQUIRES_NEW,
    isolation=Isolation.READ_COMMITTED,
    readOnly=false,
    timeout=3)
    @Override
    public void purchase(String username, String isbn) {

    try {
    Thread.sleep(5000);
    } catch (InterruptedException e) {}

    //1. 获取书的单价
    int price = bookShopDao.findBookPriceByIsbn(isbn);

    //2. 更新数的库存
    bookShopDao.updateBookStock(isbn);

    //3. 更新用户余额
    bookShopDao.updateUserAccount(username, price);
    }

    }

    Cashier.JAVA

    package com.atguigu.spring.tx;

    import java.util.List;

    public interface Cashier {

    public void checkout(String username, List<String> isbns);

    }

    CashierImpl.JAVA

    package com.atguigu.spring.tx;

    import java.util.List;

    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    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(String isbn: isbns){
    bookShopService.purchase(username, isbn);
    }
    }

    }

    BookStockException.JAVA

    package com.atguigu.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
    }


    }

    UserAccountException.JAVA

    package com.atguigu.spring.tx;

    public class UserAccountException 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
    }



    }

    SpringTransactionTest.JAVA

    package com.atguigu.spring.tx;

    import static org.junit.Assert.*;

    import java.util.Arrays;

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

    public class SpringTransactionTest {

    private ApplicationContext ctx = null;
    private BookShopDao bookShopDao = null;
    private BookShopService bookShopService = null;
    private Cashier cashier = null;

    {
    ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
    bookShopDao = ctx.getBean(BookShopDao.class);
    bookShopService = ctx.getBean(BookShopService.class);
    cashier = ctx.getBean(Cashier.class);
    }

    @Test
    public void testTransactionlPropagation(){
    cashier.checkout("AA", Arrays.asList("1001", "1002"));
    }

    @Test
    public void testBookShopService(){
    bookShopService.purchase("AA", "1001");
    }

    @Test
    public void testBookShopDaoUpdateUserAccount(){
    bookShopDao.updateUserAccount("AA", 200);
    }

    @Test
    public void testBookShopDaoUpdateBookStock(){
    bookShopDao.updateBookStock("1001");
    }

    @Test
    public void testBookShopDaoFindPriceByIsbn() {
    System.out.println(bookShopDao.findBookPriceByIsbn("1001"));
    }

    }

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  • 原文地址:https://www.cnblogs.com/yang-hao/p/5830975.html
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