Java反射测试例子

package com.reflect;

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;
		}
}

 

package com.reflect;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
public class testEg

{
	/**
	 * 通过java的反射机制获取类的所有属性和方法 */ 
	@SuppressWarnings("unchecked")
	public void test1()
	{ 
		try 
		{ 
			Class c = Class.forName("com.reflect.Customer");
			
			System.out.println("属性：");
			
			Field f[] = c.getDeclaredFields();
			
			for (int i = 0; i < f.length; i++)
			{
				System.out.println(f[i].getName());
			}
			
			System.out.println("方法：");
			
			Method m[] = c.getDeclaredMethods();
			for (int i = 0; i < m.length; i++)
			{
				System.out.println(m[i].toString());
			}
		} 
			catch (Throwable e)
			{ 
				System.err.println(e);
			}
		}
	
	/**
	 * * 通过java的反射机制动态修改对象的属性 *
	 * 
	 * @param o
	 */
	@SuppressWarnings("unchecked")
	public void test2(Customer o)
	{
		try 
		{ 
			Class c = o.getClass();
			
			// getMethod方法第一个参数指定一个需要调用的方法名称，
			//第二个参数是需要调用方法的参数类型列表，如无参数则可以指定null，该方法返回一个方法对象
		 
			Method sAge = c.getMethod("setAge", new Class[] { int.class });
			
		    Method gAge = c.getMethod("getAge",null);
		    
		    Method sName = c.getMethod("setName", new Class[] { String.class });   // 动态修改Customer对象的age
		    
		    Object[] args1 = { new Integer(25) };
		    
		    sAge.invoke(o, args1);   // 动态取得Customer对象的age
		    
		    Integer AGE = (Integer)gAge.invoke(o, null); 
		    
//		    System.out.println("AGE’Value："+AGE);
		    
		    Object[] args2 = { new String("李四") };
		    
		    sName.invoke(o, args2); 
		}
		catch (Throwable e){
			
			System.err.println(e); 
	  } 
		
  }
	/**
	 * * 通过java的反射机制做一个简单对象的克隆 *
	 * 
	 * @param o *
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public Object test3(Customer o)
	{ 
		Object o2 = null; 
		try
		{  
			Class c = o.getClass();   // 通过默认构造方法创建一个新的对象
			
			o2 = c.getConstructor(new Class[] {}).newInstance(new Object[] {});
			
			Field fields[] = c.getDeclaredFields();
			
			for (int i = 0; i < fields.length; i++)
			{ 
				Field field = fields[i];
				
				String fieldName = field.getName();
//				System.out.println(fieldName+"SS");
				
				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 = c.getMethod(getMethodName, new Class[] {});     // 获得和属性对应的setXXX()方法
				
				Method setMethod = c.getMethod(setMethodName, new Class[] { field.getType() });     // 调用原对象的getXXX()方法

				Object value = getMethod.invoke(o, new Object[] {});    // 调用拷贝对象的setXXX()方法
				
				setMethod.invoke(o2, new Object[] { value }); 
				}  
			} 
		catch (Throwable e) 
			{ 
				System.err.println(e); 
			} 
		return o2; 
	} 
	
	public static void main(String[] args) throws Exception
	{ 
		testEg t = new testEg(); 
		t.test1();
		Customer customer = new Customer(); 
		customer.setAge(20);
		customer.setName("张三");
		System.out.println("调用前name: " + customer.getName()); 
		System.out.println("调用前age: " + customer.getAge());
		t.test2(customer);
		System.out.println("调用后name: " + customer.getName()); 
		System.out.println("调用后age: " + customer.getAge());
		Customer customer2 = (Customer)t.test3(customer); 
		System.out.println("克隆对象的name: " + customer2.getName());
		System.out.println("克隆对象的age: " + customer2.getAge());
	}
	
	
		
}