获取类的成员变量

方法介绍

public class Users {
    private String username;
    private int userage;
    public int heigh;
    public int getHeigh() {
        return heigh;
    }
    public void setHeigh(int heigh) {
        this.heigh = heigh;
    }
    public Users(){
    }
    public Users(String username,int userage){
        this.userage=userage;
        this.username=username;
    }
    private Users(int userage){
        this.userage=userage;
    }
    public Users(String username){
        this.username=username;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public int getUserage() {
        return userage;
    }
    public void setUserage(int userage) {
        this.userage = userage;
    }
}public class Users {
    private String username;
    private int userage;
    public Users(){
    }
    public Users(String username,int userage){
        this.userage=userage;
        this.username=username;
    }
    private Users(int userage){
        this.userage=userage;
    }
    public Users(String username){
        this.username=username;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public int getUserage() {
        return userage;
    }
    public void setUserage(int userage) {
        this.userage = userage;
    }
}

获取成员变量

import java.lang.reflect.Field;
public class GetField {
    public static void main(String[] args) throws NoSuchFieldException {
        Class clazz= Users.class;
        Field[] fields=clazz.getFields();
        for(Field f:fields){
            System.out.println(f);
            System.out.println(f.getName());
        }
        System.out.println("-------------");
        Field[] fields1 =clazz.getDeclaredFields();
        for(Field f:fields1){
            System.out.println(f);
            System.out.println(f.getName());
        }
        System.out.println("---------------");
        //Field field = clazz.getField("userage");  //会报错，因为uerage是private类型变量
        //System.out.println(field);
        System.out.println("----------------");
        Field field1 = clazz.getDeclaredField("userage");
        System.out.println(field1);
    }
}

操作成员变量

import java.lang.reflect.Field;
public class GetField2 {
    public static void main(String[] args) throws Exception {
        Class clazz = Users.class;
        Field field = clazz.getField("heigh");   //不能是pribate类型变量，应为无法重新赋值
        //对象实例化
        Object obj=clazz.newInstance();
        //为成员变量赋予新的值
        field.set(obj,176);
        //获取成员变量的值
        Object o = field.get(obj);
        System.out.println(o);
    }
}