反射案例

案例一：
1． Test.java

package com.test;

public class Test {
	private String name="hello";
	
	public String getName(){
		return name;
	}
}

2． TestMain.java

package com.test;

import java.lang.reflect.Field;

public class TestMain {
     public static void main(String[] args) throws Exception {
		Test test=new Test();
		
		Class clz=Test.class;
		
		Field field=clz.getDeclaredField("name");
		
		field.setAccessible(true);
		
		field.set(test, "world");
		
		System.out.println(test.getName());
	}
}

案例二：
模仿框架中底层原理
1. ReflectTester.java

package com.test.reflection;

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

public class ReflectTester
{
	public Object copy(Object object) throws Exception
	{
		// 获得对象的类型
		Class classType = object.getClass();
		System.out.println("Class:" + classType.getName());

		// 通过默认构造方法创建一个新的对象
		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;
	}
}