Java中的反射

java的反射原理：

 

测试类：

package com.jlee.test;

public class MyBean {

	private Integer id ;
	private String name ;
	private Long amount ;
	private boolean isRight ;
	private double num ;
	
	private static String clazzProperty ;
	
	public static String getClazzProperty() {
		return clazzProperty;
	}
	public static void setClazzProperty(String clazzProperty) {
		MyBean.clazzProperty = clazzProperty;
	}

	private MyTest myTest ;
	
	public MyTest getMyTest() {
		return myTest;
	}
	public void setMyTest(MyTest myTest) {
		this.myTest = myTest;
	}
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Long getAmount() {
		return amount;
	}
	public void setAmount(Long amount) {
		this.amount = amount;
	}
	public boolean getIsRight() {
		return isRight;
	}
	public void setIsRight(boolean isRight) {
		this.isRight = isRight;
	}
	public double getNum() {
		return num;
	}
	public void setNum(double num) {
		this.num = num;
	}
	
	public static String staticMethod(String arg){
		return "执行类方法......." + arg;
	}
	
	@Override
	public String toString() {
		return "bean的值   id:"+this.getId()+"   name:"+this.getName()
				+"   num:"+this.getNum()+"  amount:"+this.getAmount() 
				+ "  isRight:" + this.getIsRight()+"  类属性："+this.getClazzProperty();
	}
	
}

 

 

反射实现类：

package com.jlee.test;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import com.jlee.test.MyBean;
/**
 * 
 * @author JLee
 * @Date 2010-3-2
 */
public class TestReflaction {

	public static void main(String[] args)throws Exception {
		MyBean bean = new MyBean();
		
		bean.setAmount(Long.parseLong("123123"));
		bean.setId(2);
		bean.setIsRight(false);
		bean.setName("jlee01");
		bean.setNum(1);
		System.out.println("修改前："+bean.toString());
		
		TestReflaction t = new TestReflaction();
		t.mf1(bean, "name", "jlee02");
		t.mf1(bean, "num", 2) ;
		System.out.println("第一次修改："+bean.toString());
		
		
		t.mf2("com.jlee.test.MyBean", "clazzProperty", "static");
		System.out.println("第二次修改："+bean.toString());
		
		Class[] argTypes = new Class[]{String.class};
		Object[] args1 = new Object[]{"jlee03"};
		t.mf3(bean, "setName", argTypes, args1);
		System.out.println("第三次修改："+bean.toString());
		
		String str = t.mf4("com.jlee.test.MyBean", "staticMethod", new Class[]{String.class}, new Object[]{"结束"});
		System.out.println(str);
	}
	
	
	//直接操作对象属性
	public void mf1(Object o , String fieldName ,Object newValue)throws Exception {
		Class c = o.getClass() ;
		Field f = c.getDeclaredField(fieldName);
		f.setAccessible(true);   
		f.set(o, newValue);
	}
	
	//直接操作类(Static)属性
	public void mf2(String className, String fieldName ,Object newValue)throws Exception {
		Class c = Class.forName(className) ;
		Field f = c.getDeclaredField(fieldName);
		f.setAccessible(true);   
		Object fv = f.get(c);
		f.set(c, newValue);
	}
	
	//调用对象成员方法
	public void mf3(Object o,String methodName,Class[] argTypes,Object[] args)throws Exception{
		Class c = o.getClass() ;
		Method m = c.getDeclaredMethod(methodName, argTypes);
		Object result = m.invoke(o, args);
	}
	
	//调用类成员方法(static的方法)
	public String mf4(String className,String methodName,Class[] argTypes,Object[] args)throws Exception{
		Class c = Class.forName(className);
		Method m = c.getDeclaredMethod(methodName, argTypes);
		Object result = m.invoke(null, args);
		return result.toString() ;
	}
}