【Java反射】反射获取Class、Constructor、Field、Method的方式

package com.coding.reflect;/*** @time 2023-02-22-10:16*/public class Car {//属性private String name;private int age;private String color;//无参数构造public Car() {}//有参数构造public Car(String name, int age, String color) {this.name = name;this.age = age;this.color = color;}//普通方法private void run() {System.out.println("私有方法-run.....");}//get和set方法public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getColor() {return color;}public void setColor(String color) {this.color = color;}@Overridepublic String toString() {return "Car{" +"name='" + name + '\'' +", age=" + age +", color='" + color + '\'' +'}';}
}

如下是相应的获取方式

public class TestCar {//1、获取Class对象多种方式@Testpublic void test01() throws Exception {//1 类名.classClass clazz1 = Car.class;//2 对象.getClass()Class clazz2 = new Car().getClass();//3 Class.forName("全路径")Class clazz3 = Class.forName("com.coding.reflect.Car");//实例化Car car = (Car)clazz3.getConstructor().newInstance();System.out.println(car);}//2、获取构造方法@Testpublic void test02() throws Exception {Class clazz = Car.class;//获取所有构造// getConstructors()获取所有public的构造方法
//        Constructor[] constructors = clazz.getConstructors();// getDeclaredConstructors()获取所有的构造方法public  privateConstructor[] constructors = clazz.getDeclaredConstructors();for (Constructor c:constructors) {System.out.println("方法名称："+c.getName()+" 参数个数："+c.getParameterCount());}//指定有参数构造创建对象//1 构造public
//        Constructor c1 = clazz.getConstructor(String.class, int.class, String.class);
//        Car car1 = (Car)c1.newInstance("夏利", 10, "红色");
//        System.out.println(car1);//2 构造privateConstructor c2 = clazz.getDeclaredConstructor(String.class, int.class, String.class);c2.setAccessible(true);Car car2 = (Car)c2.newInstance("捷达", 15, "白色");System.out.println(car2);}//3、获取属性@Testpublic void test03() throws Exception {Class clazz = Car.class;Car car = (Car)clazz.getDeclaredConstructor().newInstance();//获取所有public属性//Field[] fields = clazz.getFields();//获取所有属性（包含私有属性）Field[] fields = clazz.getDeclaredFields();for (Field field:fields) {if(field.getName().equals("name")) {//设置允许访问field.setAccessible(true);field.set(car,"五菱宏光");System.out.println(car);}System.out.println(field.getName());}}//4、获取方法@Testpublic void test04() throws Exception {Car car = new Car("奔驰",10,"黑色");Class clazz = car.getClass();//1 public方法Method[] methods = clazz.getMethods();for (Method m1:methods) {//System.out.println(m1.getName());//执行方法 toStringif(m1.getName().equals("toString")) {String invoke = (String)m1.invoke(car);//System.out.println("toString执行了："+invoke);}}//2 private方法Method[] methodsAll = clazz.getDeclaredMethods();for (Method m:methodsAll) {//执行方法 runif(m.getName().equals("run")) {m.setAccessible(true);m.invoke(car);}}}
}