[移动开发]JAVA三种获取类信息方式

目录

1、类名.class

2、对象.getClass

3、Class.forName （" 权限定名"）? 包名+类名???

建立Student测试类

public class Student {
    private int age;
    private String name;

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

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public String getName() {
        return name;
    }

    @Override
    public String toString() {
        return "Student{" +
                "age=" + age +
                ", name='" + name + '\'' +
                '}';
    }
}

1、类名.class

如：

public class Reflections  {
    public static void main(String[] args) {
        Student s = new Student();
        Class cls = Student.class;//类名.class方式获取
        Field[] fields = cls.getDeclaredFields();//获取所有类属性
        Method[] methods = cls.getDeclaredMethods();//获取所有方法
        System.out.println("类名："+ cls.getName());//获取所有类名
        System.out.println("属性：");
        for (int i = 0; i < fields.length; i++) {
            System.out.println(fields[i].toString());
        }
        System.out.println("方法名：");
        for (int i = 0; i < methods.length; i++) {
            System.out.println(methods[i].toString());
        }
    }
}

?运行结果：

?2、对象.getClass

public class Reflections  {
    public static void main(String[] args) {
        Student s = new Student();
        Class cls = s.getClass();//对象.getClass
        Field[] fields = cls.getDeclaredFields();//获取所有类属性
        Method[] methods = cls.getDeclaredMethods();//获取所有方法
        System.out.println("类名："+ cls.getName());//获取所有类名
        System.out.println("属性：");
        for (int i = 0; i < fields.length; i++) {
            System.out.println(fields[i].toString());
        }
        System.out.println("方法名：");
        for (int i = 0; i < methods.length; i++) {
            System.out.println(methods[i].toString());
        }
    }
}

运行结果：

3、Class.forName （" 权限定名"）? 包名+类名???

public class Reflections  {
    public static void main(String[] args) throws ClassNotFoundException {
        Student s = new Student();
        Class cls = Class.forName("ttttt.Student");//Class.forName （" 权限定名"）?包名+类名??
        Field[] fields = cls.getDeclaredFields();//获取所有类属性
        Method[] methods = cls.getDeclaredMethods();//获取所有方法
        System.out.println("类名："+ cls.getName());//获取所有类名
        System.out.println("属性：");
        for (int i = 0; i < fields.length; i++) {
            System.out.println(fields[i].toString());
        }
        System.out.println("方法名：");
        for (int i = 0; i < methods.length; i++) {
            System.out.println(methods[i].toString());
        }
    }
}

通过对比三张结果可知没有任何区别

下篇是利用反射机制改变类信息

Java利用反射机制改变对象属性（暴力）_张DD的小铺子的博客-CSDN博客