Java：反射的常用用法，

package reflection;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;

public class testReflection {

    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
        String str="reflection.T";
        //获取类
        Class c=Class.forName(str);
        //获取类路径
        URL z=c.getResource("");
        URL s=c.getClassLoader().getResource("");
        //得到class在类中的地址
        ClassLoader d=c.getClassLoader();
        //得到class，c所实现的接口Class[] f=c.getInterfaces()[0];
        Class[] f=c.getInterfaces();
        System.out.println(z);
        System.out.println(s);
        System.out.println(d);
        System.out.println(f);
        //getClassLoader().getResource(fileName)
        //用获取到的类new一个新的对象
        Object o=c.newInstance();
        //接收该对象中所有的方法
        Method[] method = c.getMethods();
        System.out.println("此元素上的注释："+c.getDeclaredAnnotations());
        for(Method m:method) {
            if(m.getName().equals("m")) {
            //方法选择第一个参数传递对象，后面的参数传递方法参数
            m.invoke(o);
            
            System.out.println("哈希码："+m.hashCode());
            }
            
            if(m.getName().equals("b")) {
                m.invoke(o,1,2);
                //得到参数类型
                for(Class paramtype : m.getParameterTypes()) {
                System.out.println("参数类型："+paramtype.getName());
                    }
            }
        }
    }
    
}
/*
//instanceof方法测试args返回的是否是一个class实例
 if(args[0] instanceof  String)

 * @param args
 * */
class T {
    public T(){
        System.out.println("构造函数被调用了");
    }
    public void m() {
        System.out.println("m函数被调用了");
        
    }
    public void b(int i,int j) {
        System.out.println("b函数的结果:"+i+j);
    }
}

package proxy;

public class Notice{
     String type;
     String name;
     String data;
     String address;
     String vill;
     String upFile;
     String num;

     public String getName() {
          return name;
     }

     public void setName(String name) {
          this.name = name;
     }

     public String getData() {
          return data;
     }

     public void setData(String data) {
          this.data = data;
     }

     public String getAddress() {
          return address;
     }

     public void setAddress(String address) {
          this.address = address;
     }

     public String getVill() {
          return vill;
     }

     public void setVill(String vill) {
          this.vill = vill;
     }

     public String getUpFile() {
          return upFile;
     }

     public void setUpFile(String upFile) {
          this.upFile = upFile;
     }

     public String getNum() {
          return num;
     }

     public void setNum(String num) {
          this.num = num;
     }

     public String getType() {
          return type;
     }

     public void setType(String type) {
          this.type = type;
     }
}

package cn.test;

import java.lang.reflect.Field;
import java.util.HashMap;

public class ReflectDemo {
    static HashMap<String,String> data;
    static{
         data=new HashMap<String,String>();
           data.put("name","拟征收土地公告");
          data.put("type","测试公告");
          data.put("data","2017-01-12");
          data.put("address","成都市青羊区");
          data.put("vill","二道街");
          data.put("upFile","文件具体的内容");
          data.put("num","文号:国:001");
          data.put("type","测试公告");


    }

    public static void main(String[] args)throws Exception {
        Notice obj=new Notice();
        test2(obj,data);
        System.out.println(obj.getAddress());
    }

    public static void test2(Notice obj,HashMap<String,String> data) throws Exception {
         Class cls=obj.getClass();
         //getDeclaredFields()：获得某个类的所有声明的字段
         Field[] fields = cls.getDeclaredFields();
           for(Field field : fields){
               String item=data.get(field.getName());
                field.set(obj,item);
           }
    }


}

package proxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class myProxyDemo implements InvocationHandler{

    Object aa;
    public Object newProxy(Object aa) {
        this.aa=aa;
        //返回一个指定接口的代理类实例（获取类加载地址，获取类实现的接口）
        return Proxy.newProxyInstance(aa.getClass().getClassLoader(),aa.getClass().getInterfaces(), this);
    }
    int count;
    public int count() {
        return count;
    }
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        befor(method,args);
        //调用此实例
        Object ad = method.invoke(this.aa,args);
        return null;
    }
　　　//可通过重写此方法完成不同功能
    public void befor(Method method, Object[] args){
        System.out.println("----------");
        
    }

}

public class TestProxy {
　　//UserManager一个普通的javabeen
    public static void main(String[] args) {
        myProxyDemo handler=new myProxyDemo ();
        UserManager userManager=(UserManager) handler.newProxy(new UserManagerImpl());
        userManager.addUser("ad", "da");
    }
}