spring学习笔记07：AOP事务注解版

Dear 丶 2024-04-17 15:57 29阅读 0赞

# 一、导包(下面用一个转账的例子来实现)： #

<properties>
      		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      		<junit.version>4.12</junit.version>
      		<c3p0.version>0.9.5.2</c3p0.version>
      		<mysql.version>5.1.38</mysql.version>
      		<spring.version>5.0.8.RELEASE</spring.version>
      		<aspect.version>1.8.10</aspect.version>
      </properties>
      <dependencies>
      
      <dependency>
    			<groupId>org.aspectj</groupId>
    			<artifactId>aspectjweaver</artifactId>
    			<version>${aspect.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.aspectj</groupId>
    			<artifactId>aspectjrt</artifactId>
    			<version>${aspect.version}</version>
    		</dependency>
      
      
      <dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-context</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    	
    		<dependency>
    		    <groupId>org.springframework</groupId>
    		    <artifactId>spring-jdbc</artifactId>
    		    <version>${spring.version}</version>
    		</dependency>
    	
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-test</artifactId>
    			<version>${spring.version}</version>
    			<scope>test</scope>
    		</dependency>
    		
    	<dependency>
    	    <groupId>mysql</groupId>
    	    <artifactId>mysql-connector-java</artifactId>
    	    <version>${mysql.version}</version>
    	</dependency>
    		
    		<dependency>
    			<groupId>com.mchange</groupId>
    			<artifactId>c3p0</artifactId>
    			<version>${c3p0.version}</version>
    		</dependency>
      
        <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>${junit.version}</version>
          <scope>test</scope>
        </dependency>
      </dependencies>

# 二、创建Account实体类 #

public class Account {
    	private int id;
    	private String name;
    	private double money;
    	public int getId() {
    		return id;
    	}
    	public void setId(int id) {
    		this.id = id;
    	}
    	public String getName() {
    		return name;
    	}
    	public void setName(String name) {
    		this.name = name;
    	}
    	public double getMoney() {
    		return money;
    	}
    	public void setMoney(double money) {
    		this.money = money;
    	}
    	
    }

# 三、创建对应的dao #

#### 接口 ####

public interface AccountDao {
    	//减钱操作
    	public void reduce(int id,double money);
    	//加钱操作
    	public void increase(int id,double money);
    }

#### 实现类（我继承的JdbcDaoSupport,可以直接获取JdbcTemplate） ####

public class AccountDaoImpl extends JdbcDaoSupport implements AccountDao{
    	//减钱操作
    	@Override
    	public void reduce(int id, double money) {
    		String sql = "update t_account set money=money-? where id=?";
    		this.getJdbcTemplate().update(sql, money,id);
    	}
    	//加钱操作
    	@Override
    	public void increase(int id, double money) {
    		String sql = "update t_account set money=money+? where id=?";
    		this.getJdbcTemplate().update(sql, money,id);
    	}
    
    }

# 四、创建对应的service #

#### 接口 ####

public interface AccountService {
    	//转账
    	public void transfer(int id1, int id2, double money);
    }

#### 实现类 ####

//@Transactional开启事务管理，在类前面表示整个的所有方法都开启事务管理
    @Transactional(isolation=Isolation.DEFAULT,propagation=Propagation.REQUIRED,readOnly=false)
    public class AccountServiceImpl implements AccountService{
    	@Resource(name="accountDao")
    	private AccountDao accountDao;
    	
    	
    	public void setAccountDao(AccountDao accountDao) {
    		this.accountDao = accountDao;
    	}
    
    
    	@Override
    	public void transfer(int id1, int id2, double money) {
    		//先减钱
    		accountDao.reduce(id1,money);
    		
    		//增加异常
    		//int a = 1/0;
    		
    		//再加钱
    		accountDao.increase(id2, money);
    	}
    
    }

# 五、创建对一个数据库 #

![数据库][20190828110652876.png]  
插入两条测试数据：  
![在这里插入图片描述][20190828111157569.png]

# 六、配置文件（注解事务的配置文件比非注解事务少了很多配置的步骤，`<tx:annotation-driven/>开启注解即可`） #

<?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"
    	xmlns:aop="http://www.springframework.org/schema/aop"
    	
    	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/tx 
    	http://www.springframework.org/schema/tx/spring-tx.xsd
    	http://www.springframework.org/schema/aop
    	http://www.springframework.org/schema/aop/spring-aop.xsd">
    	
    	<context:property-placeholder location="classpath:db.properties"/>
    	
    	<bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    		<property name="driverClass" value="${dataSource.driverClassName}"/>
    		<property name="jdbcUrl" 	 value="${dataSource.url}"/>
    		<property name="user" 		 value="${dataSource.username}"/>
    		<property name="password" 	 value="${dataSource.password}"/>
    	</bean>
    	
    	<bean name="accountDao" class="com.spring_demo.transaction.dao.AccountDaoImpl">
    		<property name="dataSource" ref="dataSource"/>
    	</bean>
    	
    	<bean name="accountService" class="com.spring_demo.transaction.service.AccountServiceImpl">
    		<property name="accountDao" ref="accountDao"/>
    	</bean>
    	
    	<context:annotation-config/>
    	
    	
    	<bean name="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    		<property name="dataSource" ref="dataSource"/>
    	</bean>
    	
    	<tx:annotation-driven/>
    </beans>

## isolation是隔离级别 propagation是传播行为 ； ##

[aop的隔离级别和传播行为][aop]

# 七、测试 #

@RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration("classpath:applicationContext-transaction.xml")
    public class TestTransaction {
    	@Resource(name="accountService")
    	private AccountService accountService;
    	
    	@Test
    	public void test1() {
            //转账50
    		accountService.transfer(1, 2, 50);
    	}
    }

# 八、测试结果 #

##### 正常情况下，执行测试代码，查看数据库，转账成功 #####

##### 转账过程出现异常（往AccountServiceImpl的transfer方法加入`int a=1/0;`），没有增加事务管理的话会出现A给B转钱，A扣了钱，B 却没有收到钱；增加事务管理后出现异常数据库会回滚，所以不会发生丢钱的结果： #####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0NoT0xn_size_16_color_FFFFFF_t_70]

##### 注意：@Transactional放置的位置既可以是类前面，也可以是方法前面，放在类前面表示该类所有方法都开启事务管理，放在方法前面表示该方法开启事务管。 #####

##### 当多个方法需要开启事务管理时，最后在类前面设置注解@Transactional，如果类中的方法大多数的readOnly=true,那类前面就设置readOnly=true，然后在特殊方法设置添加@Transactional并设置readOnly=true；反过来也是一样（有点类似全局变量和局部变量的感觉，遵循就近原则） #####

[20190828110652876.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/7e2c34182eec45e4854c06367d1fea11.png
[20190828111157569.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/7ef9ed0f201f430c88e514204a204101.png
[aop]: https://blog.csdn.net/daiqinge/article/details/51179126
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0NoT0xn_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/44f71669132643a99e721e75d5871378.png