Java反射与动态代理

/**
 * @FileName    DumpMethods.java
 * @Description 
 * @author      looton@163.com
 * @Time        
 */

import java.lang.reflect.Method;

public class DumpMethods {
	public static void main(String args[]) throws Exception {
		// 加载并初始化命令行参数指定的类
		Class<?> classType = Class.forName(args[0]);
		// 获得类的所有方法
		Method methods[] = classType.getDeclaredMethods();
		for (int i = 0; i < methods.length; i++) {
			System.out.println(methods[i].toString());
		}
	}
}

/**
 * @FileName    ReflectTester.java
 * @Description 
 * @author      looton@163.com
 * @Time        
 */

import java.lang.reflect.Field;
import java.lang.reflect.Method;

public class ReflectTester {
	public Object copy(Object object) throws Exception {
		// 获得对象的类的类型
		Class<?> classType = object.getClass();
		System.out.println("Class:" + classType.getName());
		// 先调用Class类的getConstructor()方法获得一个Constructor
		// 对象，它代表默认的构造方法，然后调用Constructor对象的newInstance()方法构造一个实例。
		Object objectCopy = classType.getConstructor(new Class[] {}).newInstance(new Object[] {});
		// 获得对象的所有属性
		Field fields[] = classType.getDeclaredFields();
		for (int i = 0; i < fields.length; i++) {
			Field field = fields[i];
			String fieldName = field.getName();
			String firstLetter = fieldName.substring(0, 1).toUpperCase();
			// 获得和属性对应的getXXX()方法的名字
			String getMethodName = "get" + firstLetter + fieldName.substring(1);
			// 获得和属性对应的setXXX()方法的名字
			String setMethodName = "set" + firstLetter + fieldName.substring(1);
			// 获得和属性对应的getXXX()方法
			Method getMethod = classType.getMethod(getMethodName, new Class[] {});
			// 获得和属性对应的setXXX()方法
			Method setMethod = classType.getMethod(setMethodName, new Class[] { field.getType() });
			// 调用原对象的getXXX()方法
			Object value = getMethod.invoke(object, new Object[] {});
			System.out.println(fieldName + ":" + value);
			// 调用拷贝对象的setXXX()方法
			setMethod.invoke(objectCopy, new Object[] { value });
		}
		return objectCopy;
	}

	public static void main(String[] args) throws Exception {
		Customer customer = new Customer("Tom", 21);
		customer.setId(new Long(1));
		Customer customerCopy = (Customer) new ReflectTester().copy(customer);
		System.out.println("Copy information:" + customerCopy.getId() + " " + customerCopy.getName() + " "
				+ customerCopy.getAge());
	}
}

class Customer {
	private Long id;
	private String name;
	private int age;

	public Customer() {
	}

	public Customer(String name, int age) {
		this.name = name;
		this.age = age;
	}

	public Long getId() {
		return id;
	}

	public void setId(Long id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

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

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}
}

/**
 * @FileName    InvokeTester.java
 * @Description 
 * @author      looton@163.com
 * @Time        
 */

import java.lang.reflect.Method;

public class InvokeTester {
	public int add(int param1, int param2) {
		return param1 + param2;
	}

	public String echo(String msg) {
		return "echo: " + msg;
	}

	public static void main(String[] args) throws Exception {
		// 获得类的类型
		Class<?> classType = InvokeTester.class;
		// 生成实例
		Object invokeTester = classType.newInstance();

		// 调用InvokeTester对象的add()方法
		Method addMethod = classType.getMethod("add", new Class[] { int.class, int.class });
		// 对带有指定参数的指定对象调用由此 Method 对象表示的底层方法。
		Object result = addMethod.invoke(invokeTester, new Object[] { 100, 200 });
		System.out.println(result);

		// 调用InvokeTester对象的echo()方法
		Method echoMethod = classType.getMethod("echo", new Class[] { String.class });
		result = echoMethod.invoke(invokeTester, new Object[] { "Hello" });
		System.out.println(result);
	}
}

//抽象角色
abstract public class Subject{
    abstract public void request();
}

//真实角色：实现了Subject的request()方法
public class RealSubject extends Subject{
    public RealSubject(){
    }
    public void request(){
        System.out.println("局长办事了！");
    }
}

//代理角色
public class ProxySubject extends Subject{
  private RealSubject realSubject; // 以真实角色作为代理角色的属性
  public ProxySubject(){
  }
　// 该方法封装了真实对象的request方法
  public void request(){
      preRequest();
      if (realSubject == null){
          realSubject = new RealSubject();
      }
      realSubject.request(); // 此处执行真实对象的request方法
      postRequest();
  }
  private void preRequest(){
     	  System.out.println("秘书去找局长");
  }
  private void postRequest(){
	  System.out.println("秘书回来了");
  }
}

//客户端调用
public class Client{
    public static void main(String[] args){
        Subject sub = new ProxySubject();
        sub.request();
    }
}