13.spring基于纯注解的声明式事务控制(*)

spring基于纯注解的声明式事务控制(*)

了解即可，真实项目中不建议使用这种方式

一、纯注解配置步骤

1). 配置数据库连接信息jdbcConfig.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/spring_01
jdbc.username=root
jdbc.password=abc123

2). 配置jdbcConfig jdbcTemplate与数据源

DataSourceTransactionManager类中有个属性nestedTransactionAllowed ，表示允许【嵌套事务】，基于此原理，然后再基于切面编程(被代理方法前后增强)，实现嵌套事务！

package config;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

import javax.sql.DataSource;

/**
 * 和连接数据库相关的配置类
 */
public class JdbcConfig {

    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;

    @Bean(name = "jdbcTemplate")
    public JdbcTemplate createJdbcTemplate(DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }

    @Bean(name="dataSource")
    public DataSource createDataSource() {
        DriverManagerDataSource ds = new DriverManagerDataSource();
        ds.setDriverClassName(driver);
        ds.setUrl(url);
        ds.setUsername(username);
        ds.setPassword(password);

        return ds;
    }
}

3). 配置 事务管理器TransactionConfig --- 切面

package config;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import javax.sql.DataSource;

/**
 * 和事务相关的配置类
 */
public class TransactionConfig {

    /** 创建事务管理器对象 */
    @Bean(name="transactionManager")
    public PlatformTransactionManager createTransactionManager(DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
}

4). 配置综合配置类SpringConfiguration

相当于applicationContext.xml;其中@EnableTransactionManagement表示开启事务

package config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.PropertySource;
import org.springframework.transaction.annotation.EnableTransactionManagement;

/**
 * spring的配置类，相当于applicationContext.xml
 */
@Configuration
@ComponentScan("com.itheima")
@Import({JdbcConfig.class,TransactionConfig.class})
@PropertySource("jdbcConfig.properties")
@EnableTransactionManagement // 开启事务
public class SpringConfiguration {
}

二、项目其他源代码

1). 项目结构

---

spring基于纯注解的声明式事务控制.png

2). Account pojo

省略get/set/toString方法

public class Account {
    private Integer id;
    private String name;
    private Float money;
    ...

3). MyJdbcDaoSupport 抽离的jdbcTemplate

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

/** 如果使用注解开发，需要自己抽离JdbcTemplate */
@Component("myJdbcDaoSupport")
public class MyJdbcDaoSupport {

    // 下面这部分就需要在配置文件中进行配置
    @Autowired
    private JdbcTemplate jdbcTemplate;
    public JdbcTemplate getJdbcTemplate() {
        return jdbcTemplate;
    }

}

4). dao持久层

import com.itheima.domain.Account;
import java.sql.SQLException;
public interface AccountDao {

    /** 根据id查询账户的余额 */
    public Account queryMoney(Integer id) throws SQLException;

    /** 根据id更新账户的余额 */
    public int updateMoney(Integer id, Float money) throws SQLException;
}

import com.itheima.dao.AccountDao;
import com.itheima.domain.Account;
import com.itheima.utils.MyJdbcDaoSupport;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.stereotype.Repository;

import java.sql.SQLException;

@Repository("accountDao")
public class AccountDaoImpl extends MyJdbcDaoSupport implements AccountDao {

    /** @事务
     * 根据id查询账户的余额，将异常显示抛出 */
    @Override
    public Account queryMoney(Integer id) throws SQLException {
        return super.getJdbcTemplate().queryForObject("select money from account where id = ?",
                new BeanPropertyRowMapper(Account.class), id);
    }

    /** @事务
     * 根据id更新账户的余额, 将异常显示抛出 */
    @Override
    public int updateMoney(Integer id, Float money) throws SQLException {
        return super.getJdbcTemplate().update("update account set money = ? where id = ?",
                money, id);
    }
}

5). service业务层

public interface AccountService {
    /** 转账业务 */
    public boolean transfer(Integer fromId, Integer toId, Float money) throws Exception;
}

package com.itheima.service.impl;

import com.itheima.dao.AccountDao;
import com.itheima.domain.Account;
import com.itheima.service.AccountService;
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("accountService")
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true)
public class AccountServiceImpl implements AccountService {

    @Autowired
    private AccountDao accountDao;

    /** @事务
     * 转账业务 使用注解进行声明式事务处理，使用
     * @Transactional 注解，并在其中配置参数*/
    @Override
    @Transactional(propagation = Propagation.SUPPORTS, readOnly = false)
    public boolean transfer(Integer fromId, Integer toId, Float money) throws Exception {
        // 1. 查询原账户余额
        Account fromMoney = accountDao.queryMoney(fromId);

        if (fromMoney.getMoney() < money) {
            throw new RuntimeException("账户余额不足，无法完成转账");
        }

        // 2. 查询被转入账户的余额
        Account toMoney = accountDao.queryMoney(toId);

        // 3. 扣除原账户的money
        accountDao.updateMoney(fromId, fromMoney.getMoney() - money);

        // 显示抛出一个异常。
        //int a = 8 / 0;

        // 4. 添加被转入账户的余额
        accountDao.updateMoney(toId, toMoney.getMoney() + money);

        return true;
    }
}

6). Junit4测试代码

import config.SpringConfiguration;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfiguration.class)
public class MyTest {
    @Autowired
    private ApplicationContext ac;

    /** 转账测试 */
    @Test
    public void testTransfer() throws Exception {
        AccountService service = (AccountService)ac.getBean("accountService");
        boolean res = service.transfer(4, 2, 1000F);
        System.out.println(res);
    }
}

7). maven工程坐标

        
            mysql
            mysql-connector-java
            5.1.41
        
        
            org.springframework
            spring-beans
            5.0.3.RELEASE
        
        
            org.springframework
            spring-context
            5.0.3.RELEASE
        
        
            org.springframework
            spring-core
            5.0.3.RELEASE
        
        
            org.springframework
            spring-expression
            5.0.3.RELEASE
        
        
            org.springframework
            spring-aop
            5.0.3.RELEASE
        
        
            org.springframework
            spring-test
            5.0.2.RELEASE
        
        
            junit
            junit
            4.12
            test
        
        
        
            org.aspectj
            aspectjweaver
            1.8.7
        
        
            org.springframework
            spring-jdbc
            5.0.2.RELEASE