- 使用AOP前，先了解下JavaProxy和Cglib的用法。
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| package com.example.springboot;
import com.wzl.entity.UserService;
import com.wzl.entity.UserServiceImpl;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
public class JavaProxyTest {
public static void main(String[] args) {
final UserServiceImpl userServiceImpl = new UserServiceImpl();
UserService userService = (UserService) Proxy.newProxyInstance(JavaProxyTest.class.getClassLoader(),
new Class[]{UserService.class}, new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println("前置通知");
try {
method.invoke(userServiceImpl, args);
} catch (IllegalAccessException e) {
System.out.println("异常通知");
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
System.out.println("后置通知");
return null;
}
});
userService.getName();
}
}
|
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| package com.example.springboot;
import com.wzl.entity.UserService;
import com.wzl.entity.UserServiceImpl;
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;
import java.lang.reflect.Method;
public class CglibTest {
public static void main(String[] args) {
UserServiceImpl userServiceImpl = new UserServiceImpl();
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(UserServiceImpl.class);
enhancer.setCallback(new MethodInterceptor() {
@Override
public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
System.out.println("前置方法");
Object result = null;
try {
result = methodProxy.invoke(userServiceImpl, objects);
} catch (Throwable throwable) {
System.out.println("异常通知");
throwable.printStackTrace();
}
System.out.println("后置方法");
return result;
}
});
UserService userService = (UserService) enhancer.create();
userService.getName();
}
}
|
SpringAop的写法
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| public void createProxyTest(){
Object target = new UserServiceImpl();
ProxyFactory pf = new ProxyFactory(target);
UserService service = (UserService)pf.getProxy();
service.getName();
}
|
看下效果
我在UserServiceImpl的方法里写了
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| @Override
public void getName() {
System.out.printf("My Name is Tom");
}
|
看下控制台的输出
高级用法 通过设置表达式
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| public void createProxyAspectByTest(){
Object target = new UserServiceImpl();
AspectJProxyFactory pf = new AspectJProxyFactory(target);
AspectJExpressionPointcutAdvisor advisor = new AspectJExpressionPointcutAdvisor();
advisor.setExpression("execution(* *.getName(..))");
pf.addAdvisor(advisor);
UserService service = (UserService)pf.getProxy();
service.getName();
service.setName();
}
|
分析下这张图：
addAdvisor 添加通知
Advisor和pointcut 添加适配器
getProxy生成Prox createAopProxy
一个需要注意的地方：根据接口或者配置来决定是否使用JavaProxy
