java 代理機制的實例詳解
前言：
java代理分靜態代理和動態代理，動態代理有jdk代理和cglib代理兩種，在運行時生成新的子類class文件。本文主要練習下動態代理，代碼用于備忘。對于代理的原理和機制，網上有很多寫的很好的，就不班門弄斧了。
jdk代理
實例代碼
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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
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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
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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; @Aspectpublic 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異常的時候調用 * @param pjp * @throws Throwable */ @Around("anyMethod()") public void invoke(ProceedingJoinPoint pjp) throws Throwable{ pjp.proceed(); } } |
以上就是java代理機制的實例，如有疑問請留言或者到本站社區交流討論，感謝閱讀，希望能幫助到大家，謝謝大家對本站的支持！
原文鏈接：http://sheungxin.iteye.com/blog/2346329
