java-通过反射获取目标类的属性,方法,构造器

首先定义一个urse

 package com.studay_fanshe;

 public class User {
     private String uname;
     private int age;
     private int id;

     public User() {
     }

     public User(String uname, int age, int id) {
         this.uname = uname;
         this.age = age;
         this.id = id;
     }

     public String getUname() {
         return uname;
     }
     public void setUname(){
         this.uname="七月";
     }
     public void setUname(String uname) {
         this.uname = uname;
     }

     public int getAge() {
         return age;
     }

     public void setAge(int age) {
         this.age = age;
     }

     public int getId() {
         return id;
     }

     public void setId(int id) {
         this.id = id;
     }
 }

 package com.studay_fanshe;

 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;

 public class test01 {
     public static void main(String[] args) throws Exception{

         Class clazz = Class.forName("com.studay_fanshe.User");
 //获取名字
         String name = clazz.getName();//获取包名+类名:com.studay_fanshe.User
         System.out.println(name);
         String simpleName = clazz.getSimpleName();//获取类名:User
         System.out.println(simpleName);
  //获取属性
         Field[] fields = clazz.getFields();//获取所有的公共的public修饰的属性
         System.out.println(fields.length);
         Field[] f = clazz.getDeclaredFields();//获取全部的属性包括私有的
         for (Field field : f) {
           /*  private java.lang.String com.studay_fanshe.User.uname
               private int com.studay_fanshe.User.age
               private int com.studay_fanshe.User.id*/
             System.out.println(field);
         }
         //获取指定属性名的属性:private java.lang.String com.studay_fanshe.User.uname
         Field uname = clazz.getDeclaredField("uname");
         System.out.println(uname);
 //获取方法
         Method[] methods = clazz.getMethods();//获取指定类中所有的方法
         for (Method method : methods) {
             System.out.println("所有的方法:"+method);
         }
         //获取指定类中公有的方法
         Method[] m = clazz.getDeclaredMethods();
         for (Method method : m) {
             System.out.println("public公有的方法"+method);
         }
         System.out.println("--------------------------------------------");
       /*  public void setUname(String uname) {
             this.uname = uname;
         }*/
       //有参数类型必须传入参数类型对应的class对象
         Method setUname = clazz.getDeclaredMethod("setUname", String.class);
         System.out.println(setUname);
      /*   public void setUname(){
             this.uname="七月";
         }*/
      //没有参数类型那么参2我们就写null
         Method setUname1 = clazz.getDeclaredMethod("setUname", null);
         System.out.println(setUname1);
  //获得构造器
         Constructor[] dc = clazz.getDeclaredConstructors();
         for (Constructor constructor : dc) {
             System.out.println("构造器:"+constructor);
         }
         Constructor dec = clazz.getDeclaredConstructor(String.class, int.class, int.class);
         System.out.println("指定的构造器:"+dec);
     }
 }