java 代理机制的实例详解

java 代理机制的实例详解

前言：

 java代理分静态代理和动态代理，动态代理有jdk代理和cglib代理两种，在运行时生成新的子类class文件。本文主要练习下动态代理，代码用于备忘。对于代理的原理和机制，网上有很多写的很好的，就不班门弄斧了。

jdk代理

实例代码

import java.lang.reflect.invocationhandler; 
import java.lang.reflect.method; 
import java.lang.reflect.proxy; 
 
public class proxyfactory implements invocationhandler {  
    
  private object tarjectobject;  
  
  public object creatproxyinstance(object obj) {  
    this.tarjectobject = obj; 
    return proxy.newproxyinstance(this.tarjectobject.getclass()  
        .getclassloader(), this.tarjectobject.getclass()  
        .getinterfaces(), this);  
  }  
  
  @override  
  public object invoke(object proxy, method method, object[] args)  
      throws throwable {  
    object result = null;  
    if (assessutils.isassess()) {  
      result = method.invoke(this.tarjectobject, args);  
    }else{ 
      throw new noassessexception("this server cannot run this service."); 
    } 
    return result;  
  } 
} 

cglib代理

import java.lang.reflect.method; 
import org.springframework.cglib.proxy.enhancer; 
import org.springframework.cglib.proxy.methodinterceptor; 
import org.springframework.cglib.proxy.methodproxy; 
 
public class proxycglibfactory implements methodinterceptor {  
    
  private object tarjectobject;  
  
  public object creatproxyinstance(object obj) {  
    this.tarjectobject = obj; 
    enhancer enhancer=new enhancer(); 
    enhancer.setsuperclass(this.tarjectobject.getclass()); 
    enhancer.setcallback(this); 
    return enhancer.create(); 
  } 
 
  @override 
  public object intercept(object obj, method method, object[] args, 
      methodproxy arg3) throws throwable { 
    object result = null;  
    if (assessutils.isassess()) {  
      result = method.invoke(this.tarjectobject, args);  
    }else{ 
      throw new noassessexception("this server cannot run this service."); 
    } 
    return result;  
  } 
} 

aspect注解

import org.aspectj.lang.joinpoint; 
import org.aspectj.lang.proceedingjoinpoint; 
import org.aspectj.lang.annotation.around; 
import org.aspectj.lang.annotation.aspect; 
import org.aspectj.lang.annotation.before; 
import org.aspectj.lang.annotation.pointcut; 
 
@aspect 
public class assessinterceptor { 
  @pointcut(value="execution (* com..*.*(..))") 
  private void anymethod(){}; 
   
  @before("anymethod()") 
  public void dobefore(joinpoint joinpoint) throws noassessexception{ 
    if (!assessutils.isassess()) {  
      throw new noassessexception("this server cannot run this service."); 
    } 
  } 
   
  /** 
   * around异常的时候调用 
   * @param pjp 
   * @throws throwable 
   */ 
  @around("anymethod()") 
  public void invoke(proceedingjoinpoint pjp) throws throwable{ 
    pjp.proceed();  
  } 
 
} 

以上就是java代理机制的实例，如有疑问请留言或者到本站社区交流讨论，感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！