Spring实战07——AOP切点表达式

ゝ一世哀愁。 2021-09-28 09:40 321阅读 0赞

*  Spring中通过切入点表达式定义具体切入点，其常用AOP切入点表达式定义

<table style="margin-left:5.4pt;"> 
 <tbody> 
 <tr> 
 <td style="vertical-align:top;width:126.9pt;"> 指示符 </td> 
 <td style="vertical-align:top;width:288.1pt;"> 作用 </td> 
 </tr> 
 <tr> 
 <td style="width:126.9pt;"> bean </td> 
 <td style="width:288.1pt;"> 用于匹配指定bean id的的方法执行 </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:126.9pt;"> within &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </td> 
 <td style="vertical-align:top;width:288.1pt;"> 用于匹配指定包名下类型内的方法执行 </td> 
 </tr> 
 <tr> 
 <td style="width:126.9pt;"> @annotation </td> 
 <td style="width:288.1pt;"> 用于匹配指定注解修饰的方法执行 </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:126.9pt;"> execution </td> 
 <td style="vertical-align:top;width:288.1pt;"> 用于进行细粒度方法匹配执行具体业务 </td> 
 </tr> 
 </tbody> 
</table>

--------------------

*  bean

<table> 
 <tbody> 
 <tr> 
 <td style="vertical-align:top;width:218.65pt;"> bean("userServiceImpl")) </td> 
 <td style="vertical-align:top;width:207.45pt;"> 指定一个类 </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:218.65pt;"> bean("*ServiceImpl") </td> 
 <td style="vertical-align:top;width:207.45pt;"> 指定所有的后缀为serviceImpl的类 </td> 
 </tr> 
 </tbody> 
</table>

*  within应用于类级别，实现粗粒度的切面表达式定义：

<table> 
 <tbody> 
 <tr> 
 <td style="vertical-align:top;width:218.65pt;"> within("aop.service.UserServiceImpl") </td> 
 <td style="vertical-align:top;width:207.45pt;"> 指定类，只能指定一个类 </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:218.65pt;"> within("aop.service.*") </td> 
 <td style="vertical-align:top;width:207.45pt;"> 只包括当前目录下的类 </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:218.65pt;"> within("aop.service..*") </td> 
 <td style="vertical-align:top;width:207.45pt;"> 指定当前目录包含所有子目录中的类 </td> 
 </tr> 
 </tbody> 
</table>

*   execution方法级别，细粒度的控制：语法：execution(返回值类型 包名.类名.方法名(参数列表))

<table> 
 <tbody> 
 <tr> 
 <td style="vertical-align:top;width:324.35pt;"> execution(void aop.service.UserServiceImpl.addUser()) </td> 
 <td style="vertical-align:top;width:106.3pt;"> 匹配方法 </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:324.35pt;"> execution(void aop.service.PersonServiceImpl.addUser(String)) </td> 
 <td style="vertical-align:top;width:106.3pt;"> 方法参数必须为字符串 </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:324.35pt;"> execution(* aop.service..*.*(..)) </td> 
 <td style="vertical-align:top;width:106.3pt;"> 万能配置 </td> 
 </tr> 
 </tbody> 
</table>

*  @annotaion应用于方法级别，实现细粒度的控制：

<table> 
 <tbody> 
 <tr> 
 <td style="vertical-align:top;width:262.3pt;"> @annotation(com..anno.RequestLog)) </td> 
 <td style="vertical-align:top;width:163.8pt;"> 指定一个需要实现增强功能的方法 </td> 
 </tr> 
 </tbody> 
</table>

--------------------

*   execution **实例：专辑有多首歌，播放每首歌后会显示这首歌的播放次数。**

**一.配置类实现**

1.接口

package com.qhf.aop.example04;
    
    public interface CD {
        void play(int i);
    }

2.实现类：空白CD

package com.qhf.aop.example04;
 
 import java.util.List;
 
 public class BlankCD implements CD {
 private String title;//专辑名称
 private String artist;//歌手
 private List<String> list;//歌曲
 
 public void setTitle(String title) {
 this.title = title;
 }
 
 public void setArtist(String artist) {
 this.artist = artist;
 }
 
 public void setList(List<String> list) {
 this.list = list;
 }
 
 @Override
 public void play(int i) {
 try {
 String song = list.get(i);
 System.out.print("Playing '" + song + "' by " + artist + "; ");
 } catch (Throwable e){
 System.out.print("抛异常; ");
 throw e;//必须抛出后才会执行@AfterThrowing
 }
 }
 }

3.配置类，bean实例化返回一个艾薇儿的专辑

package com.qhf.aop.example04;
 
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.EnableAspectJAutoProxy;
 
 import java.util.ArrayList;
 import java.util.List;
 
 @Configuration
 @EnableAspectJAutoProxy
 public class AopConfig {
 
 @Bean
 public BlankCD avrilCD(){
 BlankCD b = new BlankCD();
 b.setArtist("avril");
 b.setTitle("Head above water");
 
 List<String> list = new ArrayList<>();
 list.add("Head above water");
 list.add("one");
 list.add("two");
 list.add("three");
 list.add("four");
 list.add("five");
 
 b.setList(list);
 
 return b;
 }
 
 @Bean
 public PlayTimes playTimes(){
 return new PlayTimes();
 }
 }

4.切面类

@Pointcut("execution(\* com.qhf.aop.example04.BlankCD.play(int)) && args(i)")

public void pointcut(int i)\{\}

参数是int，故play(int)接受一个int 类型参数，&& args(i) 中指定参数名

package com.qhf.aop.example04;
 
 import org.aspectj.lang.annotation.*;
 
 import java.util.HashMap;
 import java.util.Map;
 
 @Aspect
 public class PlayTimes {
 private Map<Integer, Integer> map = new HashMap<>();
 
 @Pointcut("execution(* com.qhf.aop.example04.BlankCD.play(int)) && args(i)")
 public void pointcut(int i){
 
 }
 /**
 * 这首歌播放次数
 * @param i
 */
 @AfterReturning("pointcut(i)")
 public void playTimes(int i){
 int count = getPlayCount(i) + 1;
 map.put(i, count);
 System.out.println("播放次数：" + count);
 }
 
 private int getPlayCount(int i){
 return map.containsKey(i)? map.get(i): 0;
 }
 
 @AfterThrowing("pointcut(i)")
 public void noSong(int i){
 System.out.println("没有这首歌哟...");
 }
 }

5.测试

package com.qhf.aop.example04;
    
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(classes = AopConfig.class)
    public class Test {
    
        @Autowired
        private CD avrilCD;
    
        @org.junit.Test
        public void test(){
            //只有6首歌，0号也有一首歌
            avrilCD.play(1);
            avrilCD.play(0);
            avrilCD.play(1);
            avrilCD.play(2);
            avrilCD.play(3);
            avrilCD.play(4);
            avrilCD.play(3);
            avrilCD.play(5);
            try {
                avrilCD.play(6);//没有这首歌，暂时不知用什么方法
            } catch (Throwable e){
    
            }
            avrilCD.play(1);
        }
    }

6.运行结果

Playing 'one' by avril; 播放次数：1  
Playing 'Head above water' by avril; 播放次数：1  
Playing 'one' by avril; 播放次数：2  
Playing 'two' by avril; 播放次数：1  
Playing 'three' by avril; 播放次数：1  
Playing 'four' by avril; 播放次数：1  
Playing 'three' by avril; 播放次数：2  
Playing 'five' by avril; 播放次数：1  
抛异常; 没有这首歌哟...  
Playing 'one' by avril; 播放次数：3

二、xml配置实现

1.除了测试类和配置类，其他类全部除去注解

2.配置类

package com.qhf.aop.example05;
    
    import org.springframework.context.annotation.Configuration;
    import org.springframework.context.annotation.ImportResource;
    
    @Configuration
    @ImportResource("classpath:aop/example05/aop.xml")
    public class AopConfig {
    
    }

3.xml文件

<?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: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/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
 
 
 <aop:aspectj-autoproxy/>
 
 
 <bean id="playTimes" class="com.qhf.aop.example05.PlayTimes"/>
 
 <bean id="blankCD" class="com.qhf.aop.example05.BlankCD">
 <property name="title" value="Head above water"></property>
 <property name="artist" value="avril"></property>
 <property name="list">
 <list>
 <value>Head above water</value>
 <value>one</value>
 <value>two</value>
 <value>three</value>
 <value>four</value>
 <value>five</value>
 </list>
 </property>
 </bean>
 
 
 <aop:config>
 <aop:aspect ref="playTimes">
 
 <aop:pointcut id="point" expression="execution(* com.qhf.aop.example05.BlankCD.play(int)) and args(i)"/>
 <aop:after-returning method="playTimes" pointcut-ref="point"/>
 <aop:after-throwing method="noSong" pointcut-ref="point"/>
 
 </aop:aspect>
 </aop:config>
 
 </beans>

4.测试结果相同