SSM框架-AOP概述、Spring事务

16 spring整合mybatis

16.1 前情代码

1. 实体类

public class Account {private Integer id;private String name;private Double money;public Integer getId() {return id;}public void setId(Integer 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;}@Overridepublic String toString() {return "Account{" +"id=" + id +", name='" + name + '\'' +", money=" + money +'}';}
}

2. AccountDao接口

public interface AccountDao {@Insert("insert into tbl_account(name,money)values(#{name},#{money})")void save(Account account);@Delete("delete from tbl_account where id = #{id} ")void delete(Integer id);@Update("update tbl_account set name = #{name} , money = #{money} where id = #{id} ")void update(Account account);@Select("select * from tbl_account")List<Account> findAll();@Select("select * from tbl_account where id = #{id} ")Account findById(Integer id);
}

3. App实现

public class App {public static void main(String[] args) throws IOException {// 1. 创建SqlSessionFactoryBuilder对象SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();// 2. 加载SqlMapConfig.xml配置文件InputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");// 3. 创建SqlSessionFactory对象SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(inputStream);// 4. 获取SqlSessionSqlSession sqlSession = sqlSessionFactory.openSession();// 5. 执行SqlSession对象执行查询，获取结果UserAccountDao accountDao = sqlSession.getMapper(AccountDao.class);Account ac = accountDao.findById(2);System.out.println(ac);// 6. 释放资源sqlSession.close();}
}

4. AccountService接口

public interface AccountService {void save(Account account);void delete(Integer id);void update(Account account);List<Account> findAll();Account findById(Integer id);}

4. AccountServiceImpl接口实现类

public class AccountServiceImpl implements AccountService {@Autowiredprivate AccountDao accountDao;public void save(Account account) {accountDao.save(account);}public void update(Account account){accountDao.update(account);}public void delete(Integer id) {accountDao.delete(id);}public Account findById(Integer id) {return accountDao.findById(id);}public List<Account> findAll() {return accountDao.findAll();}
}

16.2 整合

1. 分析

sqlSession是工厂造出来的，已经存在，现在调用而已

sqkSessionFactory是核心对象

下面配置是围绕此对象进行的

2. pom准备

 <dependencies><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.2.10.RELEASE</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.1.16</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.6</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency><!--spring操作与数据库有关的--><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>5.2.10.RELEASE</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.3.0</version></dependency><!--spring整合一个mybits的jar包--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.3.0</version></dependency>

3. spring配置类

@Configuration
@ComponentScan("com.itheima")
@PropertySource("classpath:jdbc.properties")
@Import({JdbcConfig.class,MybatisConfig.class})
public class SpringConfig {}

4. 自动状态JdbcConfig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;@Beanpublic DataSource dataSource(){DruidDataSource ds = new DruidDataSource();ds.setDriverClassName(driver);ds.setUrl(url);ds.setUsername(userName);ds.setPassword(password);return ds;}
}

5. 注解简化mybatis配置

public class MybatisConfig {//定义bean，SqlSessionFactoryBean，用于产生SqlSessionFactory对象@Beanpublic SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){SqlSessionFactoryBean ssfb = new SqlSessionFactoryBean();ssfb.setTypeAliasesPackage("com.itheima.domain");ssfb.setDataSource(dataSource);return ssfb;}//定义bean，返回MapperScannerConfigurer对象@Beanpublic MapperScannerConfigurer mapperScannerConfigurer(){MapperScannerConfigurer msc = new MapperScannerConfigurer();msc.setBasePackage("com.itheima.dao");return msc;}
}

6. 原来App类不要了，重新写App2

public class App2 {public static void main(String[] args) {ApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);AccountService accountService = ctx.getBean(AccountService.class);Account ac = accountService.findById(1);System.out.println(ac);}
}

17 Spring整合junit

1. maven准备

    <!--junit包--><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version></dependency><!--spring整合junit--><dependency><groupId>org.springframework</groupId><artifactId>spring-test</artifactId><version>5.2.10.RELEASE</version></dependency>

2. 写测试方法

junit就相当于不用走main方法直接执行

//设定类运行器
@RunWith(SpringJUnit4ClassRunner.class)
//配置上下文
@ContextConfiguration(classes = SpringConfig.class)
public class AccountServiceTest {//测业务层接口//自动装配@Autowiredprivate AccountService accountService;//写测试方法@Testpublic void testFindById(){//直接掉方法就可以啦System.out.println(accountService.findById(2));}}

18 AOP

18.1 AOP简介

1. 简介

AOP面向切面编程，一种编程规范，指导开发者如何组织程序结构

2. 作用

在不惊动原始设计的基础上为其进行功能增强

3. 原理

将原来想要其他方法也拥有的功能代码抽取出来，把这块东西抽取出来成method单独的方法

给原来就有的方法取名叫做连接点

给需要追加功能的方法叫做切入点

追加的共性功能的方法(method)中叫做通知

通知方法所在的类叫做通知类

通知和切入点关系叫做切面

18.2 AOP入门案例

1. 步骤分析

• 导入AOP坐标(pom.xml)
• 制作连接点方法(原始操作，Dao接口与实现类)
• 制作共性功能(通知类与通知)
• 定义切入点
• 绑定切入点和通知关系(切面)

2. pom包导入依赖

导入context的时候，aop的包也自动导入了

导入aspectj的包

    <dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.2.10.RELEASE</version></dependency><dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId><version>1.9.4</version></dependency>

3. BookDaoImpl，制作连接点方法

• 接口

public interface BookDao {public void save();public void update();
}

• 实现类

@Repository
public class BookDaoImpl implements BookDao {public void save() {System.out.println(System.currentTimeMillis());System.out.println("book dao save ...");}public void update(){System.out.println("book dao update ...");}
}

4. 制作连接点方法以及定义切入点

• 新建一个类advice写这个

//4.通知类必须配置成Spring管理的bean
@Component
//5.设置当前类为切面类类，spring就会把这个当作aop处理
@Aspect
public class MyAdvice {//2.定义切入点，要求配置在方法上方@Pointcut("execution(void com.itheima.dao.BookDao.update())")private void pt(){}//3.设置在切入点pt()的前面运行当前操作（前置通知）@Before("pt()")//1.共性功能public void method(){System.out.println(System.currentTimeMillis());}
}

• spring配置类也要写一个

@Configuration
@ComponentScan("com.itheima")
//开启注解开发AOP功能，跟@Aspect一起的
@EnableAspectJAutoProxy
public class SpringConfig {
}

• App入口

public class App {public static void main(String[] args) {ApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);BookDao bookDao = ctx.getBean(BookDao.class);bookDao.update();}
}

• 输出结果

1668245211570
book dao save ...

18.3 AOP的工作流程

1. 流程

• Spring容器启动
• 读取所有切面配置中的切入点
• 初始化bean，判断bean对应的类中的方法是否匹配到任意切入点
  • 匹配失败，创建对象
  • 匹配成功，创建原始对象(目标对象)的代理对象
• 执行bean执行方法
  • 获取bean，调用方法并执行，完成操作
  • 获取bean是代理对象时，根据代理对象的运行模式运行原始方法和增强方法的内容，完成操作

2. 实操

• 匹配的上

System.out.println(bookDao);打印出来是System.out.println(bookDao);

System.out.println(bookDao.getClass());打印出来是class com.sun.proxy.$Proxy19

• 匹配不上

System.out.println(bookDao);打印出来是System.out.println(bookDao);

System.out.println(bookDao.getClass());打印出来是class com.itheima.dao.impl.BookDaoImpl

• 总结

打印对象不准确，因为对tostring进行重写了，所以看到的是一个样的

打印.class发现是由代理完成的实现的

18.4 AOP切入点表达式

1. 语法格式

• 类型

  • 按照接口描述

  • 按照接口实现类描述，但一般不用，耦合度高

• 切入点表达式标准格式

• 实例

    @Pointcut("execution(void com.itheima.dao.BookDao.update())")@Pointcut("execution(void com.itheima.dao.impl.BookDaoImpl.update())")

2. 通配符

• *：表示任意

    @Pointcut("execution(* com.itheima.dao.impl.BookDaoImpl.update())")//出@Pointcut("execution(* com.itheima.dao.impl.BookDaoImpl.update(*))")//不出，因此*表示至少一个

• …：表示多个连续的任意符号，即没有或者多个

    @Pointcut("execution(void *..update())")@Pointcut("execution(* *..*(..))")//表示匹配工程中的所有东西，电脑估计会炸，一般不用@Pointcut("execution(* *..u*(..))")//u开头的方法

• +：专用于匹配子类类型

3. 技巧与规范

18.5 AOP通知类型

1. 概念

描述了抽取的共性功能，根据共性功能抽取的位置不同，最终运行代码时要将其加入到合理的位置

2. 类型

• 前置通知
• 后置通知
• 环绕通知(重点)
• 返回后通知(了解)
• 抛出异常后通知(了解)

3. 运用

• 前置

public class MyAdvice {@Pointcut("execution(void com.itheima.dao.BookDao.update())")private void pt(){}//@Before：前置通知，在原始方法运行之前执行@Before("pt()")public void before() {System.out.println("before advice ...");}
}

• 后置

    //@After：后置通知，在原始方法运行之后执行@After("pt()")public void after() {System.out.println("after advice ...");}

• 环绕通知

需要加上对原始操作的调用

    //@Around：环绕通知，在原始方法运行的前后执行@Around("pt()")public Object around(ProceedingJoinPoint pjp) throws Throwable {System.out.println("around before advice ...");//表示对原始操作的调用Object ret = pjp.proceed();System.out.println("around after advice ...");return ret;}

如果接口有返回值,@Around需要返回Object，通过 pjp.proceed()进行返回值的接收

public interface BookDao {public int select();
}

public class BookDaoImpl implements BookDao {public int select() {System.out.println("book dao select is running ...");
//        int i = 1/0;return 100;}
}

    @Around("pt2()")public Object aroundSelect(ProceedingJoinPoint pjp) throws Throwable {System.out.println("around before advice ...");//表示对原始操作的调用Integer ret = (Integer) pjp.proceed();System.out.println("around after advice ...");return ret;}

• 返回后通知(了解)

与After的区别是要求原始方法执行过程中未出现异常现象

    //@AfterReturning：返回后通知，在原始方法执行完毕后运行，且原始方法执行过程中未出现异常现象@AfterReturning("pt2()")public void afterReturning() {System.out.println("afterReturning advice ...");}

• 抛出异常后通知

    //@AfterThrowing：抛出异常后通知，在原始方法执行过程中出现异常后运行@AfterThrowing("pt2()")public void afterThrowing() {System.out.println("afterThrowing advice ...");}

18.6 测试业务层接口万次执行效率

1. 需求

任意业务层接口执行均可显示其执行效率(执行时长)

2. 分析

• 业务功能：业务层接口执行前后分别记录时间，求差值得到执行效率
• 通知类型选择前后均可以增强的类型—环绕通知

3. 前情代码

• jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/spring_db?useSSL=false
jdbc.username=root
jdbc.password=123456

• 配置类JdbcConfig

package com.itheima.config;import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;import javax.sql.DataSource;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;@Beanpublic DataSource dataSource(){DruidDataSource ds = new DruidDataSource();ds.setDriverClassName(driver);ds.setUrl(url);ds.setUsername(userName);ds.setPassword(password);return ds;}
}

• 配置类MybatisConfig

import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.context.annotation.Bean;import javax.sql.DataSource;public class MybatisConfig {@Beanpublic SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){SqlSessionFactoryBean ssfb = new SqlSessionFactoryBean();ssfb.setTypeAliasesPackage("com.itheima.domain");ssfb.setDataSource(dataSource);return ssfb;}@Beanpublic MapperScannerConfigurer mapperScannerConfigurer(){MapperScannerConfigurer msc = new MapperScannerConfigurer();msc.setBasePackage("com.itheima.dao");return msc;}
}

• spring配置类SpringConfig

import org.springframework.context.annotation.*;@Configuration
@ComponentScan("com.itheima")
@PropertySource("classpath:jdbc.properties")
@Import({JdbcConfig.class,MybatisConfig.class})
public class SpringConfig {
}

• 实体类Account

package com.itheima.domain;import java.io.Serializable;public class Account implements Serializable {private Integer id;private String name;private Double money;public Integer getId() {return id;}public void setId(Integer 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;}@Overridepublic String toString() {return "Account{" +"id=" + id +", name='" + name + '\'' +", money=" + money +'}';}
}

• AccountDao接口(使用mybatis)

public interface AccountDao {@Insert("insert into tbl_account(name,money)values(#{name},#{money})")void save(Account account);@Delete("delete from tbl_account where id = #{id} ")void delete(Integer id);@Update("update tbl_account set name = #{name} , money = #{money} where id = #{id} ")void update(Account account);@Select("select * from tbl_account")List<Account> findAll();@Select("select * from tbl_account where id = #{id} ")Account findById(Integer id);
}

• AccountService接口

package com.itheima.service;import com.itheima.domain.Account;import java.util.List;public interface AccountService {void save(Account account);void delete(Integer id);void update(Account account);List<Account> findAll();Account findById(Integer id);
}

• AccountServiceImpl接口实现类

import java.util.List;
@Service
public class AccountServiceImpl implements AccountService {@Autowiredprivate AccountDao accountDao;@Overridepublic void save(Account account) {accountDao.save(account);}@Overridepublic void delete(Integer id) {accountDao.delete(id);}@Overridepublic void update(Account account) {accountDao.update(account);}@Overridepublic List<Account> findAll() {return accountDao.findAll() ;}@Overridepublic Account findById(Integer id) {return accountDao.findById(id);}
}

• 测试代码

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfig.class)
public class AccountServiceTestCase {@Autowiredprivate AccountService accountService;@Testpublic void testFindById(){Account ac = accountService.findById(2);System.out.println(ac);}@Testpublic void testFindAll(){List<Account> all = accountService.findAll();System.out.println(all);}
}

4. 进行aop设置

• 打开aop注解

@Configuration
@ComponentScan("com.itheima")
@PropertySource("classpath:jdbc.properties")
@Import({JdbcConfig.class,MybatisConfig.class})
@EnableAspectJAutoProxy
public class SpringConfig {
}

• 写aop的类

@Component
//切片类
@Aspect
public class ProjectAdvice {//匹配业务层的所有方法@Pointcut("execution(* com.itheima.service.*Service.*(..))")private void servicePt(){};@Around("ProjectAdvice.servicePt()")public void runSpeed(ProceedingJoinPoint pjp) throws Throwable {//签名信息Signature signature = pjp.getSignature();//接口类型String className = signature.getDeclaringTypeName();//接口方法String methodName = signature.getName();//原始操作前来个记录时间long start = System.currentTimeMillis();for (int i = 0; i < 10000; i++) {//执行原始操作，不需要返回值了，直接查询10000遍pjp.proceed();}//结束后long end = System.currentTimeMillis();System.out.println("万次执行:"+className+"."+methodName+"---->"+(end-start)+"ms");}
}

• 测试代码

@Service
public class AccountServiceImpl implements AccountService {@Autowiredprivate AccountDao accountDao;@Overridepublic void save(Account account) {accountDao.save(account);}@Overridepublic void delete(Integer id) {accountDao.delete(id);}@Overridepublic void update(Account account) {accountDao.update(account);}@Overridepublic List<Account> findAll() {return accountDao.findAll() ;}@Overridepublic Account findById(Integer id) {return accountDao.findById(id);}
}

• 结果

万次执行:com.itheima.service.AccountService.findAll---->2148ms
万次执行:com.itheima.service.AccountService.findById---->1280ms

18.7 AOP通知获取数据

1. 代码

• before

@Component
@Aspect
public class MyAdvice {@Pointcut("execution(* com.itheima.dao.BookDao.findName(..))")private void pt(){}//JoinPoint：用于描述切入点的对象，必须配置成通知方法中的第一个参数，可用于获取原始方法调用的参数@Before("pt()")public void before(JoinPoint jp) {//用JoinPoint返回参数，返回的是数组Object[] args = jp.getArgs();System.out.println(Arrays.toString(args));System.out.println("before advice ..." );}}

• around

正常运行是id为100，可以在中间更改参数，变成600

可以运用到参过来的参数有问题(例如数据格式、数据问题)，可以处理

    //ProceedingJoinPoint：专用于环绕通知，是JoinPoint子类，可以实现对原始方法的调用，直接getArgs//@Around("pt()")public Object around(ProceedingJoinPoint pjp) {Object[] args = pjp.getArgs();System.out.println(Arrays.toString(args));//更改args数值，再作为参数扔进去args[0] = 666;Object ret = null;try {ret = pjp.proceed(args);} catch (Throwable t) {t.printStackTrace();}return ret;}

• afterReturning

returning = "ret"与String ret以及JoinPoint和String同时存在

    //设置返回后通知获取原始方法的返回值，要求returning属性值必须与方法形参名相同@AfterReturning(value = "pt()",returning = "ret")//JoinPoint和String同时存在，JoinPoint得放前面public void afterReturning(JoinPoint jp,String ret) {System.out.println("afterReturning advice ..."+ret);}

• AfterThrowing

throwing = "t"与(Throwable t)

    //设置抛出异常后通知获取原始方法运行时抛出的异常对象，要求throwing属性值必须与方法形参名相同，即形参是返回对象@AfterThrowing(value = "pt()",throwing = "t")public void afterThrowing(Throwable t) {System.out.println("afterThrowing advice ..."+t);}

    public String findName(int id,String password) {System.out.println("id:" + id);//故意来个异常，给AfterThrowing接收if (true) throw new NullPointerException();return "itcast";}

输出

id:100
afterThrowing advice ...java.lang.NullPointerException
Exception in thread "main" java.lang.NullPointerException

2. 总结

• around用proceedingjoinpoint，其他用joinpoint

18.8 案例：百度网盘密码数据兼容处理

1. 需求

在业务方法执行之前对所有的输入参数进行格式处理——trim()

2. 分析

使用处理后的参数调用原始方法——环绕通知中存在对原始方法的调用

3. 前情代码

• maven

 <dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.2.10.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>5.2.10.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-test</artifactId><version>5.2.10.RELEASE</version></dependency><dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId><version>1.9.4</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.1.16</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.6</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.3.0</version></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version><scope>test</scope></dependency>

• 配置类

@Configuration
@ComponentScan("com.itheima")
public class SpringConfig {
}

• ResourcesDao接口

public interface ResourcesDao {boolean readResources(String url, String password);
}

• ResourcesDaoImpl接口实现类

@Repository
public class ResourcesDaoImpl implements ResourcesDao {public boolean readResources(String url, String password) {System.out.println(password.length());//模拟校验return password.equals("root");}
}

• ResourcesService

public interface ResourcesService {public boolean openURL(String url, String password);
}

• ResourcesServiceImpl接口实现类

@Service
public class ResourcesServiceImpl implements ResourcesService {@Autowiredprivate ResourcesDao resourcesDao;public boolean openURL(String url, String password) {return resourcesDao.readResources(url,password);}
}

• App入口

public class App {public static void main(String[] args) {ApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);ResourcesService resourcesService = ctx.getBean(ResourcesService.class);boolean flag = resourcesService.openURL("http://pan.baidu.com/haha", "root");System.out.println(flag);}
}

4. 开工

• 打开aop配置类

@Configuration
@ComponentScan("com.itheima")
@EnableAspectJAutoProxy
public class SpringConfig {
}

• DataAdvice类

@Component
@Aspect
public class DataAdvice {@Pointcut("execution(boolean com.itheima.service.*Service.*(*,*))")private void servicePt(){}@Around("com.itheima.aop.DataAdvice.servicePt()")public Object trimStr(ProceedingJoinPoint pjp) throws Throwable {Object[] args = pjp.getArgs();for (int i = 0; i < args.length; i++) {//args是个对象，不一定是字符产，不用foreach循环，用fori，需要用到索引值判断是否是字符串// 判断参数是不是字符串if(args[i].getClass().equals(String.class)){//用toString转成字符串args[i] = args[i].toString().trim();}}//改完放回去哦Object ret = pjp.proceed(args);return ret;}
}

• 运行App入口类

public class App {public static void main(String[] args) {ApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);ResourcesService resourcesService = ctx.getBean(ResourcesService.class);boolean flag = resourcesService.openURL("http://pan.baidu.com/haha", "root  ");System.out.println(flag);}
}

• 输出结果

4
true

19 Spring事务

19.1 spring事务简介

1. 作用

在数据层保障一系列的数据库操作同失败同完成

spring事务作用：在数据层或业务层保障一系列的数据库操作同成功同失败

2. 需求

需求：实现任意两个账户间转账操作，A账户减钱，B账户加钱

• JDBC配置

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;@Beanpublic DataSource dataSource(){DruidDataSource ds = new DruidDataSource();ds.setDriverClassName(driver);ds.setUrl(url);ds.setUsername(userName);ds.setPassword(password);return ds;}
}

• mybatis配置

public class MybatisConfig {@Beanpublic SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){SqlSessionFactoryBean ssfb = new SqlSessionFactoryBean();ssfb.setTypeAliasesPackage("com.itheima.domain");ssfb.setDataSource(dataSource);return ssfb;}@Beanpublic MapperScannerConfigurer mapperScannerConfigurer(){MapperScannerConfigurer msc = new MapperScannerConfigurer();msc.setBasePackage("com.itheima.dao");return msc;}
}

• spring配置

@Configuration
@ComponentScan("com.itheima")
@PropertySource("classpath:jdbc.properties")
@Import({JdbcConfig.class,MybatisConfig.class})
public class SpringConfig {
}

• 数据层接口

public interface AccountDao {@Update("update tbl_account set money = money + #{money} where name = #{name}")void inMoney(@Param("name") String name, @Param("money") Double money);@Update("update tbl_account set money = money - #{money} where name = #{name}")void outMoney(@Param("name") String name, @Param("money") Double money);
}

• 业务层接口

public interface AccountService {/*** 转账操作* @param out 传出方* @param in 转入方* @param money 金额*///配置当前接口方法具有事务@Transactionalpublic void transfer(String out,String in ,Double money) ;
}

• 业务层实现类

public class AccountServiceImpl implements AccountService {@Autowiredprivate AccountDao accountDao;public void transfer(String out,String in ,Double money) {accountDao.outMoney(out,money);accountDao.inMoney(in,money);}
}

• 测试用例

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfig.class)
public class AccountServiceTest {@Autowiredprivate AccountService accountService;@Testpublic void testTransfer() throws IOException {accountService.transfer("Tom","Jerry",100D);}
}

3. 结果分析

如果中间出现异常，那么会出现A加，B不减的执行问题

@Service
public class AccountServiceImpl implements AccountService {@Autowiredprivate AccountDao accountDao;public void transfer(String out,String in ,Double money) {accountDao.outMoney(out,money);int i = 1/0;accountDao.inMoney(in,money);}}

因此在接口中开启事务

    @Transactionalpublic void transfer(String out,String in ,Double money) ;
}

并且在JdbcConfig开启事务管理器

    //配置事务管理器，mybatis使用的是jdbc事务,dataSource这个丢进去@Beanpublic PlatformTransactionManager transactionManager(DataSource dataSource){DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();transactionManager.setDataSource(dataSource);return transactionManager;}

并且在注解写上事务型驱动

@Configuration
@ComponentScan("com.itheima")
@PropertySource("classpath:jdbc.properties")
@Import({JdbcConfig.class,MybatisConfig.class})
//开启注解式事务驱动
@EnableTransactionManagement
public class SpringConfig {
}

这样运行的时候就会保证同时成功或者失败，抛出异常java.lang.ArithmeticException: / by zero

19.2 Spring事务角色

1. 场景

outMoney事务和inMoney事务都会加入到transfer事务中，就可以实现，transfer下的操作同时成功或者失败，不会出现inMoney事务出错，而outMoney事务不回滚的问题了

transfer叫做事务管理员，outMoney事务和inMoney事务叫做事务协调员

事务管理员就是发起事务方，就是发起事务的那个方法，例如transfer

事务协调员就是加入事务方，可以是数据层方法也可以是业务层方法

19.3 事务的配置

1. 配置项