spring aop advice

Z时代
2024-01-10
分类：综合

本文内容纲要：spring aop advice

1.前置通知(BeforeAdvice)：

import java.lang.reflect.Method;
import org.springframework.aop.MethodBeforeAdvice;
public class HelloBeforeAdvice implements MethodBeforeAdvice{
    public void before(Method method, Object[] args, Object target) throws Throwable {
        System.out.println("do something before some method");
    }
}

如果出现 The hierarchy of the type HelloBeforeAdvice is inconsistent错误，是缺少相关的jar或者jdk环境不对。

2.后置通知(AfterAdvice)

import java.lang.reflect.Method;
import org.springframework.aop.AfterReturningAdvice;
public class HelloAfterAdvice implements AfterReturningAdvice {
    public void afterReturning(Object result, Method method, Object[] args, Object target) throws Throwable {
        System.out.println("do something after the method");
    }
}

Test client

import org.springframework.aop.framework.ProxyFactory;

public class TestClient {

 public static void main(String[] args) {
     ProxyFactory proxyFactory = new ProxyFactory();//创建代理工厂
     proxyFactory.setTarget(new HelloImpl());
     proxyFactory.addAdvice(new HelloBeforeAdvice());
     proxyFactory.addAdvice(new HelloAfterAdvice());
     Hello helloProxy = (Hello) proxyFactory.getProxy();
     System.out.println(helloProxy.sayHello("zhangsan"));
 }

}

public class HelloImpl implements Hello {

public String sayHello(String str) {

System.out.println("hello>>>"+str);

return "hello>>>"+str;

}

环绕通知(AroundAdvice)

//aop联盟提供的接口

import org.aopalliance.intercept.MethodInterceptor;

import org.aopalliance.intercept.MethodInvocation;

public class HelloAroundAdvice implements MethodInterceptor {

 public Object invoke(MethodInvocation invocation) throws Throwable {
     System.out.println("before method>>>");
     Object result = invocation.proceed();
     System.out.println("after method>>");
     return result;
 }

}

spring 配置文件方式

 <context:component-scan base-package="com.cdv.ppms"></context:component-scan>
 <bean id="helloProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
     <property name="interfaces" value="com.cdv.ppms.Hello"/><!-- 需要代理的接口 -->
     <property name="target" ref="helloImpl"/><!-- 接口实现类 , 此处需要是ref 否则object is not an instance of declaring class-->
     <property name="interceptorNames"><!-- 拦截器 名称-->
         <list>
             <value>helloAroundAdvice</value>
         </list>
     </property>
 </bean>

import org.springframework.stereotype.Component;

@Component

public class HelloImpl implements Hello {

//...

}

@Component

public class HelloAroundAdvice implements MethodInterceptor {

//....

}

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestXMLClient {

 public static void main(String[] args) {
     ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
     Hello    hello = (Hello) context.getBean("helloProxy");
     hello.sayHello("test xml");
 }

}

抛出通知(ThrowAdvice)
import java.lang.reflect.Method;
import org.springframework.aop.ThrowsAdvice;
import org.springframework.stereotype.Component;
@Component
public class HelloThrowAdvice implements ThrowsAdvice{
public void afterThrowing(Method method, Object[] args, Object target, Exception e){
System.out.println("-------------------Throw Exception------------------------");
System.out.println("target class>>"+target.getClass().getName());
System.out.println("method class>>" + method.getName());
System.out.println("exception message>>"+e.getMessage());
System.out.println("-------------------Throw Exception------------------------");
}
}
helloAroundAdvice
testThrowAdvice
import org.springframework.stereotype.Component;
@Component
public class HelloImpl implements Hello {
```
 public String sayHello(String str) {
     System.out.println("hello>>>"+str);
     throw new RuntimeException("error>>");//加入异常以便测试
 }
```
}

引入通知(Introduction Advice)

对方法的增强叫织入（Weaving），对类的增强叫引入(Introduction)

import org.aopalliance.intercept.MethodInvocation;
import org.springframework.aop.support.DelegatingIntroductionInterceptor;
import org.springframework.stereotype.Component;
@Component
public class HelloIntroAdvice extends DelegatingIntroductionInterceptor implements Apology {
    /**
     * 
     */
    private static final long serialVersionUID = -3328637206414010549L;
    public Object invoke(MethodInvocation invocation) throws Throwable{
        return super.invoke(invocation);
    }    
    public void saySorry(String str) {
        System.out.println("introduction advice>>>"+str);
    }
}
<bean id="helloProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="interfaces" value="com.cdv.ppms.Apology"/><!-- 需要代理的接口 -->
        <property name="target" ref="helloImpl"/><!-- 接口实现类 -->
        <property name="interceptorNames"><!-- 拦截器 名称-->
            <list>
                <value>helloAroundAdvice</value>
                <value>helloThrowAdvice</value>
                <value>helloIntroAdvice</value>
            </list>
        </property>
        <property name="proxyTargetClass" value="true"></property><!--代理目标类， 默认false代理接口-->
    </bean>
    <bean id="helloImpl" class="com.cdv.ppms.HelloImpl"></bean>
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestXMLClient {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        HelloImpl    helloImpl = (HelloImpl) context.getBean("helloProxy");
        helloImpl.sayHello("test xml");
        Apology apology = (Apology) helloImpl;//将目标类向上强制转型为Apology接口， 这时引入通知给我们带来的特性， 也就是“接口动态实现”功能
        apology.saySorry("zhangsan");
    }
}

切面(Advisor)

切面(Advisor)封装了通知（Advice）和切点(Pointcut)

import org.springframework.stereotype.Component;
@Component
public class HelloImpl implements Hello {
    public String sayHello(String str) {
        System.out.println("hello>>>"+str);
        return str;
    }
    public void advisorOne(String name){
        System.out.println("advisor one>>>"+name);
    }
    public void advisorTwo(String name){
        System.out.println("advisor two>>"+name);
    }
}

在代理类中新增以advisor开头的方法，对其进行拦截

<context:component-scan base-package="com.cdv.ppms"></context:component-scan>
　　　　<!--定义切面-->
    <bean id="helloAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
        <property name="advice" ref="helloAroundAdvice"/>
        <property name="pattern" value="com.cdv.ppms.HelloImpl.advisor.*"></property><!-- 切点 (正则表达式) -->
    </bean>
    <bean id="helloProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="target" ref="helloImpl"/><!-- 接口实现类 -->
        <property name="interceptorNames" value="helloAdvisor"/>
        <property name="proxyTargetClass" value="true"></property>
    </bean>
    <bean id="helloImpl" class="com.cdv.ppms.HelloImpl"></bean>
    <bean id="helloAroundAdvice" class="com.cdv.ppms.HelloAroundAdvice"></bean>
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.springframework.stereotype.Component;
@Component
public class HelloAroundAdvice implements MethodInterceptor {
    public Object invoke(MethodInvocation invocation) throws Throwable {
        System.out.println("before method>>>");
        Object result = invocation.proceed();
        System.out.println("after method>>");
        return result;
    }
}
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestXMLClient {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        HelloImpl    helloImpl = (HelloImpl) context.getBean("helloProxy");
        helloImpl.advisorOne("11111111");
        helloImpl.advisorTwo("2222222222");
    }
}
-------------around包了两层， 有问题-------------------------------------------
before method>>>
before method>>>
advisor one>>>11111111
after method>>
after method>>
before method>>>
before method>>>
advisor two>>2222222222
after method>>
after method>>
------------------------

随着项目的扩大，上述的代理配置会越来越多。

自动代理（扫描bean名称）

定义BeanNameAutoProxyCreator,该bean是个bean后处理器，无需被引用，因此没有id属性

<context:component-scan base-package="com.cdv.ppms"></context:component-scan>
    <bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
        <property name="beanNames" value="*Impl"/><!--对以Impl结尾的类进行处理-->
        <property name="interceptorNames" value="helloAroundAdvice"/>
        <property name="optimize" value="true"/>
    </bean>
    <bean id="helloImpl" class="com.cdv.ppms.HelloImpl"></bean>
    <bean id="helloAroundAdvice" class="com.cdv.ppms.HelloAroundAdvice"></bean>

测试

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestXMLClient {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        HelloImpl    helloImpl = (HelloImpl) context.getBean("helloImpl");
        helloImpl.advisorOne("11111111");//
        helloImpl.advisorTwo("2222222222");
        helloImpl.sayHello("zhangwuji");
    }
}

自动代理(扫描切面配置)

代理将由DefaultAdvisorAutoProxyCreator自动生成，这个类可以扫描所有的切面类

<context:component-scan base-package="com.cdv.ppms"></context:component-scan>
    <bean id="helloAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
        <property name="advice" ref="helloAroundAdvice"/>
        <property name="pattern" value="com.cdv.ppms.HelloImpl.advisor.*"/>
    </bean>
    <bean class="org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator">
        <property name="optimize" value="true"/>
    </bean>
    <bean id="helloImpl" class="com.cdv.ppms.HelloImpl"></bean>
    <bean id="helloAroundAdvice" class="com.cdv.ppms.HelloAroundAdvice"></bean>

测试

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestXMLClient {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        HelloImpl    helloImpl = (HelloImpl) context.getBean("helloImpl");
        helloImpl.advisorOne("11111111");
        helloImpl.advisorTwo("2222222222");
        helloImpl.sayHello("zhangwuji");
    }
}
//只有符合advisor开头的方法才会被代理

这样在spring的配置中会存在大量的切面配置（想拦截指定注解的方法，就必须拓展DefaultPointcutAdvisor类，自定义一个切面类）。

Spring & AspectJ

11-1 基于注解：通过execution()表达式拦截方法

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class HelloAspect {
    @Around("execution(* com.cdv.ppms.HelloImpl.*(..))")//切点表达式
    public Object around(ProceedingJoinPoint pjp) throws Throwable{
        before();
        Object result = pjp.proceed();
        after();
        return result;
    }
    private void after() {
        System.out.println("hey,, after.");
    }
    private void before() {
        System.out.println("hey,, before");        
    }
}

切点表达式

execution()表示拦截的方法，挂号中定义拦截的规则

上面第一个*表示返回任意类型

第二个*表示HelloImpl类中的任意方法

..表示任意类型参数

<context:component-scan base-package="com.cdv.ppms"></context:component-scan>
    <aop:aspectj-autoproxy proxy-target-class="true"/><!-- 默认值为false只能代理接口，当为true时才能代理目标类 -->
    <bean id="helloImpl" class="com.cdv.ppms.HelloImpl"></bean>

test

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestXMLClient {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        HelloImpl    helloImpl = (HelloImpl) context.getBean("helloImpl");
        helloImpl.advisorOne("11111111");
        helloImpl.advisorTwo("2222222222");
        helloImpl.sayHello("zhangwuji");
    }
}

11-2 基于注解通过AspectJ @annotation表达式拦截方法

自定义注解

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface MyTag {
}

更改aspect类的切点表达式

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class HelloAspect {
    @Around("@annotation(com.cdv.ppms.MyTag)")
    public Object around(ProceedingJoinPoint pjp) throws Throwable{
        before();
        Object result = pjp.proceed();
        after();
        return result;
    }
    private void after() {
        System.out.println("hey,, after.");
    }
    private void before() {
        System.out.println("hey,, before");        
    }
}

该注解可以标注在方法上，运行时生效

import org.springframework.stereotype.Component;
@Component
public class HelloImpl implements Hello {
    public String sayHello(String str) {
        System.out.println("hello>>>"+str);
        return str;
    }
    @MyTag
    public void advisorOne(String name){
        System.out.println("advisor one>>>"+name);
    }
    public void advisorTwo(String name){
        System.out.println("advisor two>>"+name);
    }
}

配置

<context:component-scan base-package="com.cdv.ppms"></context:component-scan>
    <bean id="helloImpl" class="com.cdv.ppms.HelloImpl"></bean>

测试

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestXMLClient {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        HelloImpl    helloImpl = (HelloImpl) context.getBean("helloImpl");
        helloImpl.advisorOne("11111111");
        helloImpl.advisorTwo("2222222222");
        helloImpl.sayHello("zhangwuji");
    }
}

其他几个注解

@Before @After @AfterThrowing @DeclareParents引入通知 AfterReturning(返回后通知，在方法结束后执行)

11-3 引入通知

Aspect类

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.DeclareParents;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class HelloAspect {
　　　　//something need to do
    @DeclareParents(value="com.cdv.ppms.HelloImpl",defaultImpl=com.cdv.ppms.ApologyImpl.class)
    private Apology apology;
}

接口实现类

public class ApologyImpl implements Apology {
    public void saySorry(String str) {
        System.out.println("apologyImpl>>>"+str);
    }
}

配置

<context:component-scan base-package="com.cdv.ppms"></context:component-scan>
    <bean id="helloImpl" class="com.cdv.ppms.HelloImpl"></bean>

测试

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestXMLClient {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        HelloImpl    helloImpl = (HelloImpl) context.getBean("helloImpl");
        helloImpl.sayHello("zhangwuji");
        Apology apology = (Apology) helloImpl;
        apology.saySorry("hahahahah");
    }
}

本文内容总结：spring aop advice

原文链接：https://www.cnblogs.com/rocky-fang/p/5459346.html

以上是 spring aop advice 的全部内容，来源链接： utcz.com/z/362907.html