Spring学习三-AOP学习
1、实现转账功能,引入事务
1.1、实现转账功能
public void transfer(String sourceName, String targetName, BigDecimal money) {
User sourceUser = userDao.getUserByName(sourceName);
User targetUser = userDao.getUserByName(targetName);
sourceUser.setMoney(sourceUser.getMoney().subtract(money));
userDao.updateUser(sourceUser);
// 故意使其发生异常
int a = 1/0;
targetUser.setMoney(targetUser.getMoney().add(money));
userDao.updateUser(targetUser);
}
故意使其发生异常,这样导致 userDao.updateUser(sourceUser); 执行完成,userDao.updateUser(targetUser);执行未完成,导致转账过程中出现错误。
1.2、解决转账出现问题
- 添加事务,事务进行控制
- 保证当前数据库的操作是同一次连接
1.2.1、ConnectionUtils
public class ConnectionUtils {
private ThreadLocal<Connection> threadLocal = new ThreadLocal<Connection>();
public void setThreadLocal(ThreadLocal<Connection> threadLocal) {
this.threadLocal = threadLocal;
}
private DataSource dataSource;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
public Connection getThreadConnection() {
Connection connection = threadLocal.get();
if (connection == null) {
try {
connection = dataSource.getConnection();
threadLocal.set(connection);
} catch (SQLException e) {
e.printStackTrace();
}
}
return connection;
}
public void removeConnection(){
threadLocal.remove();
}
}
1.2.2、TransationManager
提供和事务相关的工具类,包含了开启事务,提交事务,回滚事务,释放连接
public class TransationManager {
private ConnectionUtils connectionUtils;
public void setConnectionUtils(ConnectionUtils connectionUtils) {
this.connectionUtils = connectionUtils;
}
public void beginTransation(){
try {
connectionUtils.getThreadConnection().setAutoCommit(false);
} catch (SQLException e) {
e.printStackTrace();
}
}
public void commitTransation(){
try {
connectionUtils.getThreadConnection().commit();
} catch (SQLException e) {
e.printStackTrace();
}
}
public void rollbackTransation(){
try {
connectionUtils.getThreadConnection().rollback();
} catch (SQLException e) {
e.printStackTrace();
}
}
public void releaseTransation(){
try {
connectionUtils.getThreadConnection().close();
connectionUtils.removeConnection();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
1.2.3、UserDao
package com.wmding.spring.dao;
import com.wmding.spring.bean.User;
import com.wmding.spring.utils.ConnectionUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import java.sql.SQLException;
import java.util.List;
public class UserDao {
private QueryRunner runner;
public void setRunner(QueryRunner runner) {
this.runner = runner;
}
private ConnectionUtils connectionUtils;
public void setConnectionUtils(ConnectionUtils connectionUtils) {
this.connectionUtils = connectionUtils;
}
public int saveUser(User user) {
try {
return runner.update(connectionUtils.getThreadConnection(),"insert into user(name,age,money) values(?,?,?)", user.getName(), user.getAge(), user.getMoney());
} catch (SQLException e) {
e.printStackTrace();
}
return -1;
}
public List<User> list() {
try {
return runner.query(connectionUtils.getThreadConnection(),"select * from user", new BeanListHandler<User>(User.class));
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
public int deleteUser(Integer userId) {
try {
return runner.update(connectionUtils.getThreadConnection(),"delete from user where id=?", userId);
} catch (SQLException e) {
e.printStackTrace();
}
return -1;
}
public User getUserById(Integer id) {
try {
return runner.query(connectionUtils.getThreadConnection(),"select * from user where id = ?", new BeanHandler<User>(User.class), id);
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
public void updateUser(User user) {
try {
runner.update(connectionUtils.getThreadConnection(),"update user set name = ?,age = ?,money = ? where id = ?", user.getName(), user.getAge(), user.getMoney(), user.getId());
} catch (SQLException e) {
e.printStackTrace();
}
}
public User getUserByName(String name) {
try {
List<User> query = runner.query(connectionUtils.getThreadConnection(),"select * from user where name = ?", new BeanListHandler<User>(User.class), name);
if (query == null || query.size() == 0) {
return null;
} else if (query.size() > 1) {
throw new RuntimeException("数据出错了");
} else {
return query.get(0);
}
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
}
1.2.4、UserServiceImpl
业务实现中增加事务控制
public class UserServiceImpl implements UserService {
private UserDao userDao;
private TransationManager transationManager;
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
public void setTransationManager(TransationManager transationManager) {
this.transationManager = transationManager;
}
public void transfer(String sourceName, String targetName, BigDecimal money) {
try {
// 开启事务
transationManager.beginTransation();
User sourceUser = userDao.getUserByName(sourceName);
User targetUser = userDao.getUserByName(targetName);
sourceUser.setMoney(sourceUser.getMoney().subtract(money));
userDao.updateUser(sourceUser);
int a = 1/0;
targetUser.setMoney(targetUser.getMoney().add(money));
userDao.updateUser(targetUser);
// 提交事务(业务完成)
transationManager.commitTransation();
}catch (Exception e){
// 回滚事务
transationManager.rollbackTransation();
throw new RuntimeException(e);
}finally {
// 释放连接
transationManager.releaseTransation();
}
}
}
bean.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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
<bean id="connectionUtils" class="com.wmding.spring.utils.ConnectionUtils">
<property name="dataSource" ref="dataSource"></property>
</bean>
<bean id="transationManager" class="com.wmding.spring.utils.TransationManager">
<property name="connectionUtils" ref="connectionUtils"/>
</bean>
<bean id="userService" class="com.wmding.spring.serivce.impl.UserServiceImpl">
<property name="userDao" ref="userDao"/>
<property name="transationManager" ref="transationManager"></property>
</bean>
<bean id="userDao" class="com.wmding.spring.dao.UserDao">
<property name="runner" ref="runner"/>
<property name="connectionUtils" ref="connectionUtils"/>
</bean>
<bean id="runner" class="org.apache.commons.dbutils.QueryRunner" scope="prototype">
</bean>
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="com.mysql.jdbc.Driver"/>
<property name="jdbcUrl"
value="jdbc:mysql://localhost:3306/spring?useUnicode=true&characterEncoding=utf8&autoReconnect=true&useSSL=false&serverTimezone=UTC"/>
<property name="user" value="root"/>
<property name="password" value="root"/>
</bean>
</beans>
问题虽然得到了解决,但是这样导致代码的耦合度比较高:
- UserServiceImpl 中引入了TransationManager;如果有多个方法时,都需要使用 transationManager.beginTransation(); 的方法进行添加。
1.3、使用动态代理实现业务控制
1.3.1、UserServiceImpl 中不再引入TransationManager来控制事务
public class UserServiceImpl implements UserService {
private UserDao userDao;
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
public int saveUser(User user) {
return userDao.saveUser(user);
}
public List<User> list() {
return userDao.list();
}
public int deleteUser(Integer userId) {
return userDao.deleteUser(userId);
}
public User getUserById(Integer id) {
return userDao.getUserById(id);
}
public User getUserByName(String name) {
return userDao.getUserByName(name);
}
public void updateUser(User user) {
userDao.updateUser(user);
}
public void transfer(String sourceName, String targetName, BigDecimal money) {
User sourceUser = userDao.getUserByName(sourceName);
User targetUser = userDao.getUserByName(targetName);
sourceUser.setMoney(sourceUser.getMoney().subtract(money));
userDao.updateUser(sourceUser);
int a = 1/0;
targetUser.setMoney(targetUser.getMoney().add(money));
userDao.updateUser(targetUser);
}
}
1.3.2、用于创建Service的代理对象的工厂
public class BeanFactory {
private UserServiceImpl userService;
public void setUserService(UserServiceImpl userService) {
this.userService = userService;
}
private TransationManager transationManager;
public void setTransationManager(TransationManager transationManager) {
this.transationManager = transationManager;
}
/**
* 获取代理对象
*
* @return
*/
public UserService getUserService() {
return (UserService) Proxy.newProxyInstance(UserServiceImpl.class.getClassLoader(), UserServiceImpl.class.getInterfaces(),
new InvocationHandler() {
public Object invoke(Object proxy, Method method, Object[] args) {
Object rtValue;
try {
// 开启事务
transationManager.beginTransation();
// 执行操作
rtValue = method.invoke(userService, args);
// 提交事务
transationManager.commitTransation();
return rtValue;
} catch (Exception e) {
// 事务回滚
transationManager.rollbackTransation();
throw new RuntimeException(e);
} finally {
// 事务关闭,断开连接
transationManager.releaseTransation();
}
}
});
}
}
在该类中,使用动态代理来添加事务控制。省去之前在 UserServiceImpl 的每个方法中进行事务控制。
1.3.3、bean.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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
<bean id="connectionUtils" class="com.wmding.spring.utils.ConnectionUtils">
<property name="dataSource" ref="dataSource"></property>
</bean>
<bean id="transationManager" class="com.wmding.spring.utils.TransationManager">
<property name="connectionUtils" ref="connectionUtils"/>
</bean>
<bean id="userService" class="com.wmding.spring.serivce.impl.UserServiceImpl">
<property name="userDao" ref="userDao"/>
</bean>
<bean id="userDao" class="com.wmding.spring.dao.UserDao">
<property name="runner" ref="runner"/>
<property name="connectionUtils" ref="connectionUtils"/>
</bean>
<bean id="runner" class="org.apache.commons.dbutils.QueryRunner" scope="prototype">
</bean>
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="com.mysql.jdbc.Driver"/>
<property name="jdbcUrl"
value="jdbc:mysql://localhost:3306/spring?useUnicode=true&characterEncoding=utf8&autoReconnect=true&useSSL=false&serverTimezone=UTC"/>
<property name="user" value="root"/>
<property name="password" value="root"/>
</bean>
<bean id="beanFactory" class="com.wmding.spring.BeanFactory">
<property name="transationManager" ref="transationManager"/>
<property name="userService" ref="userService"/>
</bean>
<bean id="userServiceProxy" factory-bean="beanFactory" factory-method="getUserService"/>
</beans>
1.3.4、测试
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:bean.xml")
public class UserTest {
/**
* 使用userService的代理
*/
@Autowired
@Qualifier("userServiceProxy")
private UserService userService;
@Test
public void transfer() {
userService.transfer("aaa", "bbb", new BigDecimal(100));
}
}
2、AOP
2.1、AOP的基本概念
AOP :Aspect oriented Programming(面向切面编程)
作用:在程序运行期间,不修改源码对已有方法进行增强
优势:减少重复代码、提供开发效率、方便维护
实现原理:动态代理
动态代理常用的有两种方式:
- 基于接口的
- 提供者:JDK 提供的 Proxy 类
- 要求:被代理类最少实现一个接口
- 基于子类的动态代理
- 提供者:第三方jar。CGLib
- 要求:被代理类不能用 final 修饰的类(即不能是最终类)
3、Spring 中的 AOP
3.1、Spring中配置 AOP
3.1.1、pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.wmding.spring</groupId>
<artifactId>spring-demo-aop01</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.2.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>5.2.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.9.5</version>
</dependency>
</dependencies>
</project>
3.1.2、Logger
public class Logger {
public void beforePrintLog(){
System.out.println("前置通知打印日志");
}
public void afterRunningPrintLog(){
System.out.println("后置通知打印日志");
}
public void afterThrowingPrintLog(){
System.out.println("异常通知打印日志");
}
public void afterPrintLog(){
System.out.println("最终通知打印日志");
}
}
3.1.3、bean.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: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
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
https://www.springframework.org/schema/aop/spring-aop.xsd">
<bean id="logger" class="com.wmding.spring.log.Logger"/>
<bean id="userService" class="com.wmding.spring.serivce.impl.UserServiceImpl"/>
<!-- 配置切面 -->
<aop:config>
<aop:pointcut id="pt1" expression="execution(* com.wmding.spring.serivce.impl.*.*(..))"/>
<aop:aspect id="logAspect" ref="logger">
<aop:before method="beforePrintLog" pointcut-ref="pt1"/>
<aop:after-returning method="afterRunningPrintLog" pointcut-ref="pt1"/>
<aop:after-throwing method="afterThrowingPrintLog" pointcut-ref="pt1"/>
<aop:after method="afterPrintLog" pointcut-ref="pt1"/>
</aop:aspect>
</aop:config>
</beans>
3.1.4、UserServiceImpl
public class UserServiceImpl implements UserService {
public void test() {
System.out.println("UserServiceImpl 中 text 方法被执行了");
}
}
3.1.5、测试类
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:bean.xml")
public class LoggerTest {
@Autowired
private UserService userService;
@Test
public void saveUser() {
userService.test();
}
}
3.2、使用在配置文件中配置环绕通知
<?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: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
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
https://www.springframework.org/schema/aop/spring-aop.xsd">
<bean id="logger" class="com.wmding.spring.log.Logger"/>
<bean id="userService" class="com.wmding.spring.serivce.impl.UserServiceImpl"/>
<!-- 配置切面 -->
<aop:config>
<aop:pointcut id="pt1" expression="execution(* com.wmding.spring.serivce.impl.*.*(..))"/>
<aop:aspect id="logAspect" ref="logger">
<!-- <aop:before method="beforePrintLog" pointcut-ref="pt1"/>-->
<!-- <aop:after-returning method="afterRunningPrintLog" pointcut-ref="pt1"/>-->
<!-- <aop:after-throwing method="afterThrowingPrintLog" pointcut-ref="pt1"/>-->
<!-- <aop:after method="afterPrintLog" pointcut-ref="pt1"/>-->
<aop:around method="aroundPrintLog" pointcut-ref="pt1"/>
</aop:aspect>
</aop:config>
</beans>
Spring 提供了一接口 ProceedingJoinPoint,在接口的 proceed() 方法就相当于明确调用切入点方法。
该接口可以作为环绕通知的方法参数,在程序执行时,Spring 会为我们提供该接口的实现类供我们使用。
public class Logger {
/**
* 环绕通知
*/
public Object aroundPrintLog(ProceedingJoinPoint proceedingJoinPoint) {
Object[] args = proceedingJoinPoint.getArgs();
Object proceed = null;
try {
System.out.println("前置通知打印日志");
proceed = proceedingJoinPoint.proceed(args);
System.out.println("后置通知打印日志");
return proceed;
} catch (Throwable throwable) {
System.out.println("异常通知打印日志");
throw new RuntimeException(throwable);
}finally {
System.out.println("最终通知打印日志");
}
}
}
3.3 基于注解的AOP
3.3.1、bean.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: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
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
https://www.springframework.org/schema/aop/spring-aop.xsd">
<context:component-scan base-package="com.wmding.spring"/>
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
</beans>
3.3.2 使用注解进行配置
@Component("log")
@Aspect
public class Logger {
@Pointcut("execution(* com.wmding.spring.serivce.impl.*.*(..))")
public void p1(){}
@Before("p1()")
public void beforePrintLog() {
System.out.println("前置通知打印日志");
}
@AfterReturning("p1()")
public void afterRunningPrintLog() {
System.out.println("后置通知打印日志");
}
@AfterThrowing("p1()")
public void afterThrowingPrintLog() {
System.out.println("异常通知打印日志");
}
@After("p1()")
public void afterPrintLog() {
System.out.println("最终通知打印日志");
}
/**
* 环绕通知
*/
public Object aroundPrintLog(ProceedingJoinPoint proceedingJoinPoint) {
Object[] args = proceedingJoinPoint.getArgs();
Object proceed = null;
try {
System.out.println("前置通知打印日志");
proceed = proceedingJoinPoint.proceed(args);
System.out.println("后置通知打印日志");
return proceed;
} catch (Throwable throwable) {
System.out.println("异常通知打印日志");
throw new RuntimeException(throwable);
}finally {
System.out.println("最终通知打印日志");
}
}
}