Java反射之剖析方法

  1 package cn.rt.gwq;
  2 
  3 import java.util.List;
  4 
  5 public class Person {
  6     
  7     public String value = "public  value";
  8     
  9     /**
 10      *无参数构造函数
 11      */
 12     public Person() {
 13         System.out.println("no params constructor");
 14     }
 15     
 16     /**
 17      * 一个参数的构造函数
 18      * @param name
 19      */
 20     public Person(String name) {
 21         System.out.println("string name constructor");
 22         value = "change the value : "+name;
 23     }
 24     
 25     /**
 26      * 一个参数的构造函数
 27      * @param age
 28      */
 29     public Person(int age) {
 30         System.out.println("int age constructor");
 31         value = "change the value : "+age;
 32     }
 33     
 34     /**
 35      * 多个参数的构造函数
 36      * @param usm
 37      * @param pwd
 38      */
 39     public Person(String usm,String pwd) {
 40         System.out.println("String usm,String pwd constructor");
 41         value = "change the value : "+usm +":"+pwd;
 42     }
 43     
 44     /**
 45      * 私有的构造函数
 46      * @param list
 47      */
 48     private Person(List list) {
 49         System.out.println("List constructor");
 50         value = "change the value : "+list.toArray().toString();
 51     }
 52     ////////
 53     
 54     
 55     
 56     
 57     
 58     
 59     
 60     
 61     ////////
 62     /**
 63      *无参数方法
 64      */
 65     public void eat(){
 66         System.out.println("eating soup...");
 67     }
 68     
 69     /**
 70      * 有参数方法
 71      * @param food
 72      */
 73     public void eat(String food){
 74         System.out.println(food + "is delicious...");
 75     }
 76     
 77     /**
 78      * 有返回值的方法
 79      * @param food
 80      * @return
 81      */
 82     public String eat(String name,String food){
 83         System.out.println(food + "is good,"+name+", try it.");
 84         return food;
 85     }
 86     
 87     /**
 88      * 私有方法
 89      */
 90     private void work(){
 91         System.out.println("I don‘t like to work.");
 92     }
 93     
 94     /**
 95      * 静态方法
 96      */
 97     public static void sleep(){
 98         System.out.println("I‘m sleeping ....");
 99     }
100     
101 
102 
103 }

  1 package cn.rt.gwq;
  2 
  3 import java.lang.reflect.Method;
  4 
  5 import org.junit.Test;
  6 
  7 /**
  8  * 反射方法的测试demo
  9  * @author Administrator
 10  *
 11  */
 12 public class Demo_MtdRft {
 13 
 14     /**
 15      * 反射没有参数的公开方法
 16      * @throws Exception
 17      */
 18     @Test
 19     public void test1() throws Exception{
 20         
 21         Person person = new Person();
 22         //加载类
 23         Class clazz = Class.forName("cn.rt.gwq.Person");
 24         //获取方法
 25         Method method = clazz.getMethod("eat", null);
 26         //执行方法
 27         method.invoke(person, null);
 28         
 29         return;
 30         
 31     }
 32     
 33     /***
 34      * 反射带一个参数的方法
 35      * @throws Exception
 36      */
 37     @Test
 38     public void test2() throws Exception{
 39         
 40         Person person = new Person();
 41         
 42         Class clazz = Class.forName("cn.rt.gwq.Person");
 43         Method method = clazz.getMethod("eat", String.class);
 44         method.invoke(person, "fish");
 45         
 46         return;
 47         
 48     }
 49     
 50     /***
 51      * 反射有返回值的方法
 52      * @throws Exception
 53      */
 54     @Test
 55     public void test3() throws Exception{
 56     
 57         Person person = new Person();
 58         
 59         Class clazz = Class.forName("cn.rt.gwq.Person");
 60         Method method = clazz.getMethod("eat", String.class,String.class);
 61         String food = (String) method.invoke(person, "tom","fish");
 62         System.out.println("food :"+food);
 63         
 64         return;
 65         
 66     }
 67     
 68     /**
 69      * 反射私有方法
 70      * @throws Exception
 71      */
 72     @Test
 73     public void test4() throws Exception{
 74         
 75         Person person = new Person();
 76         
 77         Class clazz = Class.forName("cn.rt.gwq.Person");
 78         //获取私有方法
 79         Method method = clazz.getDeclaredMethod("work", null);
 80         //强制在类外可自执行
 81         method.setAccessible(true);
 82         //执行
 83         method.invoke(person, null);
 84         
 85         return;
 86         
 87     }
 88     
 89     /**
 90      * 反射静态方法
 91      * @throws Exception
 92      */
 93     @Test
 94     public void test5() throws Exception{
 95         
 96         Person person = new Person();
 97         
 98         Class clazz = Class.forName("cn.rt.gwq.Person");
 99         //也可以用getMethod方法获取
100         Method method = clazz.getDeclaredMethod("sleep", null);
101         method.setAccessible(true);
102         method.invoke(person, null);
103         
104         return;
105         
106     }
107     
108         
109 }