今天的Java学习将上节课所学习到的方法进行了测试。

1、获取成员变量，其中有方法比较特殊，我直接写在了注释中

 1 //辅类
 2 
 3 public class Person {
 4     private String name;
 5     private int age;
 6     public String a;
 7     protected String b;
 8     String c;
 9     private String d;
10 
11     public Person(String name, int age) {
12         this.name = name;
13         this.age = age;
14     }
15     public Person(){}
16 
17     public String getName() {
18         return name;
19     }
20 
21     public void setName(String name) {
22         this.name = name;
23     }
24 
25     public int getAge() {
26         return age;
27     }
28 
29     public void setAge(int age) {
30         this.age = age;
31     }
32 
33     @Override
34     public String toString() {
35         return "Person{" +
36                 "name='" + name + '\'' +
37                 ", age=" + age +
38                 ", a='" + a + '\'' +
39                 ", b='" + b + '\'' +
40                 ", c='" + c + '\'' +
41                 ", d='" + d + '\'' +
42                 '}';
43     }
44     public void eat(String food){
45         System.out.println("吃"+food);
46     }
47 
48 }

 1 //测试一，获取成员变量
 2 
 3 import java.lang.reflect.Field;
 4 
 5 public class test01 {
 6     public static void main(String[] args) throws Exception {
 7         //0.获取person的class对象
 8         Class personClass=Person.class;
 9         //获取成员变量，1、Field[] getFields()：获取
10         Field[] fields=personClass.getFields();
11         for(Field field:fields){
12             System.out.println(field);
13         }
14         System.out.println("----------");
15         //2、Field getField(String name):获取指定public成员变量
16         Field a=personClass.getField("a");
17         Person p=new Person();
18         Object value=a.get(p);
19         System.out.println(value);
20         a.set(p,"张三");
21         System.out.println(p);
22         System.out.println("------------");
23         //Field[] getDeclareFields():获取所有成员变量
24         Field[] declaredFields=personClass.getDeclaredFields();
25         for(Field declaredField:declaredFields){
26             System.out.println(declaredField);
27         }
28         //Field getDeclaredField(String name)
29         Field d= personClass.getDeclaredField("d");
30         d.setAccessible(true);//暴力反射，忽略权限检查
31         Object value1=d.get(p);
32         System.out.println(value1);
33     }
34 
35 }

 1 //获取构造方法
 2 import java.lang.reflect.Constructor;
 3 
 4 public class test02 {
 5     public static void main(String[] args) throws Exception {
 6         Class personClass=Person.class;
 7         //Constructor<T> getConstructor(类<?>...parameterTypes)
 8         Constructor c=personClass.getConstructor(String.class,int.class);
 9         System.out.println(c);
10         Object person=c.newInstance("张三",21);
11         System.out.println(person);
12         System.out.println("-------");
13         Constructor c1= personClass.getConstructor();
14         System.out.println(c1);
15         Object person1=c1.newInstance();
16         System.out.println(person1);
17     }
18 }

 1 //获取成员方法和类名
 2 import java.lang.reflect.Method;
 3 
 4 public class test03 {
 5     public static void main(String[] args) throws Exception {
 6         Class personClass=Person.class;
 7         //获取指定名称方法
 8         Method m=personClass.getMethod("eat");
 9         Person p=new Person();
10         m.invoke(p);
11         System.out.println("------------");
12         Method m1= personClass.getMethod("eat",String.class);
13         m1.invoke(p,"宵夜");
14         System.out.println("------------");
15         //获取所有public修饰方法
16         Method[] ms= personClass.getMethods();
17         for(Method me:ms){
18             System.out.println(me);
19             //String getName:获取方法名
20             String name= me.getName();
21             System.out.println(name);
22         }
23         //获取类名
24         String className=personClass.getName();
25         System.out.println(className);
26     }
27 }

其中有几个方法特殊

①setAccessible(true):忽略权限检查

②newInstance():简化获取构造方法操作

③invoke(Object obj):执行方法

④String getName:获取方法名