1.JDK動態代理
jdk動態代理必須要藉助介面才能代理物件，所以先定義介面並實現定義介面 程式碼如下
package com.day1.com.test1;
/**
* Created by leewihong on 2018/6/14.
*/
public interface test1_helloworldInterface {
public void sayHelloWorld();
}
複製程式碼介面實現程式碼
package com.day1.com.test1;
/**
* Created by leewihong on 2018/6/14.
*/
public class test1_helloworldImpl implements test1_helloworldInterface {
@Override
public void sayHelloWorld() {
System.out.println("sayhelloworld");
}
}
複製程式碼建立代理物件與真實服務物件之間的關係，然後在實現代理邏輯，因此先建立一個代理物件,這個代理物件是需要去實現import java.lang.reflect.InvocationHandler介面,他裡面定義了一個invoke方法,並提供介面陣列用於下掛代理物件,這一步相當關鍵,程式碼如下
package com.day1.com.test1;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* Created by leewihong on 2018/6/14.
*/
public class jdkexampleProxy implements InvocationHandler {
private Object targetImpl = null;
public Object bind(Object targetImpl){
this.targetImpl = targetImpl;
// 建立代理物件和真實物件之間的關係
return Proxy.newProxyInstance(targetImpl.getClass().getClassLoader(),targetImpl.getClass
().getInterfaces(),this);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println("進入代理邏輯方法");
System.out.println("在排程真實物件之前的服務");
// invoke相當於是排程了真實的方法
Object result = method.invoke(targetImpl,args);
System.out.println("在排程真實物件之後的服務");
return result;
}
}
複製程式碼動態代理測試方法
package com.day1.com.test1;
/**
* Created by leewihong on 2018/6/14.
*/
public class test1 {
public static void main(String [] args){
// 1.test1
jdkexampleProxy jdkexampleProxy = new jdkexampleProxy();
test1_helloworldInterface proxy = (test1_helloworldInterface) jdkexampleProxy.bind(new test1_helloworldImpl());
proxy.sayHelloWorld();
}
}
複製程式碼動態代理測試結果
進入代理邏輯方法
在排程真實物件之前的服務
sayhelloworld
在排程真實物件之後的服務
複製程式碼驗證args引數是否傳過去新建另外一個介面
package com.day1.com.test1;
/**
* Created by leewihong on 2018/6/14.
*/
public interface test1_hellowordinterface2 {
public void sayhelloword2(String name);
}
複製程式碼實現類如下
package com.day1.com.test1;
/**
* Created by leewihong on 2018/6/14.
*/
public class test1_hellowordimpl2 implements test1_hellowordinterface2{
@Override
public void sayhelloword2(String name) {
System.out.println(name);
}
}
複製程式碼測試程式碼
package com.day1.com.test1;
/**
* Created by leewihong on 2018/6/14.
*/
public class test1 {
public static void main(String [] args){
// 1.test1
jdkexampleProxy jdkexampleProxy = new jdkexampleProxy();
test1_helloworldInterface proxy = (test1_helloworldInterface) jdkexampleProxy.bind(new test1_helloworldImpl());
proxy.sayHelloWorld();
// 2.test2
test1_hellowordinterface2 proxy2 = (test1_hellowordinterface2) jdkexampleProxy.bind(new test1_hellowordimpl2
());
proxy2.sayhelloword2("weihong");
}
}
複製程式碼輸出結果
進入代理邏輯方法
在排程真實物件之前的服務
sayhelloworld
在排程真實物件之後的服務
進入代理邏輯方法
在排程真實物件之前的服務
weihong
在排程真實物件之後的服務
Process finished with exit code 0
複製程式碼2.攔截器
攔截器所做的一個目的其實就是需要暴漏一個介面給外部，然後將代理和介面給繫結起來，外部只需要關注介面怎麼定義和實現即可
定義攔截器介面
public interface test2_interceptor {
public boolean before(Object proxy, Object target, Method method, Object [] args);
public void around(Object proxy, Object target, Method method, Object [] args);
public void after(Object proxy, Object target, Method method, Object [] args);
}
複製程式碼實現攔截器介面
package com.day1.com.test1.com.test2;
import java.lang.reflect.Method;
/**
* Created by leewihong on 2018/6/14.
*/
public class test2_myinterceptor implements test2_interceptor {
@Override
public boolean before(Object proxy, Object target, Method method, Object[] args) {
System.out.println("反射方法前邏輯");
return false;
}
@Override
public void around(Object proxy, Object target, Method method, Object[] args) {
System.out.println("取代了了被代理物件的方法");
}
@Override
public void after(Object proxy, Object target, Method method, Object[] args) {
System.out.println("反射方法後邏輯");
}
}
複製程式碼在代理中繫結攔截介面
package com.day1.com.test1.com.test2;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* Created by leewihong on 2018/6/14.
*/
public class test2_interceptorJDKProxy implements InvocationHandler {
private Object target = null;
private String interceptorclass = null;
public test2_interceptorJDKProxy(Object target,String interceptorclass){
this.target = target;
this.interceptorclass = interceptorclass;
}
public static Object bind(Object target,String interceptorclass){
return Proxy.newProxyInstance(target.getClass().getClassLoader(),target.getClass()
.getInterfaces(),new test2_interceptorJDKProxy(target,interceptorclass));
}
@Override
public Object invoke(Object proxy,Method method, Object[] args) throws
Throwable {
if (interceptorclass == null){
// 沒有攔截器直接反射原有方法
return method.invoke(target,args);
}
Object result = null;
// 通過反射生成攔截器
test2_interceptor test2_interceptor =(test2_interceptor) Class.forName(interceptorclass).newInstance();
if (test2_interceptor.before(proxy,target,method,args))
{
// 反射原有物件方法
result = method.invoke(target,args);
}
else {
test2_interceptor.around(proxy,target,method,args);
}
test2_interceptor.after(proxy,target,method,args);
return result;
}
}
複製程式碼測試動態代理攔截器
package com.day1.com.test1.com.test2;
import com.day1.com.test1.test1_helloworldImpl;
/**
* Created by leewihong on 2018/6/14.
*/
public class test2 {
public static void main(String [] args){
test2_helloword proxy = (test2_helloword) test2_interceptorJDKProxy.bind(new
test2_hellowordImp(),"com.day1.com.test1.com.test2.test2_myinterceptor");
proxy.sayhelloword();
}
}
複製程式碼得到結果
反射方法前邏輯
取代了了被代理物件的方法
反射方法後邏輯
複製程式碼