Java反射之剖析字段

Posted 2020-07-10

通过反射获取字段：

--

反射方法并调用时，静态方法可以不传递对象。

字段有点小不同，即使是静态字段也需要传递对象

以下是测试类：包括一个测试实体类:Girl.java，一个反射测试Demo.java

Girl.java:

 1 package cn.rt.gwq;
 2 
 3 public class Girl {
 4     
 5     private int age = 18;
 6     public int height = 168;
 7     public static String name = "alice" ;
 8     
 9     public Girl() {
10         // TODO Auto-generated constructor stub
11     }
12     
13     public Girl(int age,int height,String name){
14         this.age = age;
15         this.height = height;
16         this.name = name;
17     }
18     
19 }

Demo_FieldRflt：

 1 package cn.rt.gwq;
 2 
 3 import java.lang.reflect.Field;
 4 
 5 import org.junit.Test;
 6 
 7 public class Demo_FieldRflt {
 8     
 9     /**
10      * 反射获取字段
11      * @throws Exception
12      */
13     @Test
14     public void test1() throws Exception{
15         
16         Girl girl = new Girl(18,168,"alice");
17         
18         //加载类
19         Class clazz = Class.forName("cn.rt.gwq.Girl");
20         
21         //公有字段
22         Field height = clazz.getField("height");
23         int h = (int) height.get(girl);
24         
25         //私有字段
26         Field age = clazz.getDeclaredField("age");
27         age.setAccessible(true);
28         int a = (int) age.get(girl);
29         
30         //静态字段
31         Field name = clazz.getField("name");
32         String n = (String) name.get(girl);
33         
34         //输出验证
35         System.out.println("name:"+n+",age:"+a+",height:"+h);
36     }
37 
38 }