getFields()与getDeclaredFields()区别

 

1.package study.reflection;   
2.  
3.public class People {   
4.public String name = null;   
5.private String sex = null;   
6.private String age = null;   
7.private String tel = null;   
8.private String address = null;   
9.public static String s = null;   
10.static {   
11.   System.out.println("loading People");   
12.}   
13.  
14.public static void showPeople() {   
15.  
16.}   
17.  
18.public People(String name) {   
19.   this.name = name;   
20.}   
21.  
22.private People() {   
23.   this.name = name;   
24.}   
25.  
26.private void showPeopleInfo() {   
27.   System.out.println(name + " " + sex + " " + age + " " + tel + " "  
28.     + address);   
29.}   
30.  
31.public String getName() {   
32.   return name;   
33.}   
34.  
35.public void setName(String name) {   
36.   this.name = name;   
37.}   
38.  
39.public String getSex() {   
40.   return sex;   
41.}   
42.  
43.public void setSex(String sex) {   
44.   this.sex = sex;   
45.}   
46.  
47.public String getAge() {   
48.   return age;   
49.}   
50.  
51.public void setAge(String age) {   
52.   this.age = age;   
53.}   
54.  
55.public String getTel() {   
56.   return tel;   
57.}   
58.  
59.public void setTel(String tel) {   
60.   this.tel = tel;   
61.}   
62.  
63.public String getAddress() {   
64.   return address;   
65.}   
66.  
67.public void setAddress(String address) {   
68.   this.address = address;   
69.}   
70.  
71.}   
72.  
73.package esg;   
74.  
75.import java.lang.reflect.Constructor;   
76.import java.lang.reflect.Field;   
77.import java.lang.reflect.Method;   
78.  
79.import study.reflection.People;   
80.  
81.public class Esg {   
82.  
83.public static void main(String[] a) throws ClassNotFoundException {   
84.   Class c1 = People.class;   
85.  
86.   Field[] fs = c1.getFields();   
87.   System.out.println("*******getFields()*********");   
88.   for (int i = 0; i < fs.length; i++) {   
89.    System.out.println(fs[i].getName());   
90.   }   
91.   System.out.println("*******getDeclaredFields()*********");   
92.   fs = c1.getDeclaredFields();   
93.   for (int i = 0; i < fs.length; i++) {   
94.    System.out.println(fs[i].getName());   
95.   }   
96.   System.out.println("*******getMethods()*********");   
97.   Method[] md = c1.getMethods();   
98.   for (int i = 0; i < md.length; i++) {   
99.    System.out.println(md[i].getName());   
100.   }   
101.   System.out.println("*******getDeclaredMethods()*********");   
102.   md = c1.getDeclaredMethods();   
103.   for (int i = 0; i < md.length; i++) {   
104.    System.out.println(md[i].getName());   
105.   }   
106.  
107.   System.out.println("*******getConstructors()*********");   
108.   Constructor[] con = c1.getConstructors();   
109.   for (int i = 0; i < con.length; i++) {   
110.    System.out.println(con[i].getName());   
111.   }   
112.   System.out.println("*******getDeclaredConstructors()*********");   
113.   con = c1.getDeclaredConstructors();   
114.   for (int i = 0; i < con.length; i++) {   
115.    System.out.println(con[i].getName());   
116.   }   
117.}   
118.}   

 

* getFields()与getDeclaredFields()区别:getFields()只能访问类中声明为公有的字段,私有的字段它无法访问，能访问从其它类继承来的公有方法.getDeclaredFields()能访问类中所有的字段,与public,private,protect无关，不能访问从其它类继承来的方法  

* getMethods()与getDeclaredMethods()区别:getMethods()只能访问类中声明为公有的方法,私有的方法它无法访问,能访问从其它类继承来的公有方法.getDeclaredFields()能访问类中所有的字段,与public,private,protect无关,不能访问从其它类继承来的方法  

* getConstructors()与getDeclaredConstructors()区别:getConstructors()只能访问类中声明为public的构造函数.getDeclaredConstructors()能访问类中所有的构造函数,与public,private,protect无关  

评论

3 楼 宁极而待 2014-09-16  

总结说反了吧，declare的意思是声明，所以带declared的方法才是获得类中定义的相关属性和方法。

2 楼 mxdxm 2014-07-17  

谢谢，你说的很对。

1 楼 dyy_gusi 2014-06-20  

兄弟，好像总结的有问题吧。

getFields()获得某个类的所有的公共（public）的字段，包括父类。

getDeclaredFields()获得某个类的所有申明的字段，即包括public、private和proteced，
但是不包括父类的申明字段。