JAVA反射--获取当前运行时类的属性结构

测试需要的类,接口,注解

public interface MyInterface {
    void info() throws RuntimeException, IOException;
}

/**
 * 自定义注解
 */
@Target({TYPE, FIELD, METHOD, PARAMETER, CONSTRUCTOR, LOCAL_VARIABLE})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotation {

    String value() default "hello";

}

/**
 *  父类
 */
public class Creature<T> implements Serializable {
    //性别
    private char gender;
    //体重
    public double weight;

    private void breath() {
        System.out.println("会呼吸");
    }

    public void eat() {
        System.out.println("会吃饭");
    }

}

/**
 * 学生类
 */
@MyAnnotation("学生类")
public class Student extends Creature<String> implements Comparable<String>, MyInterface {

    public int id;
    private String name;
    int age;

    public Student() {
    }

    @MyAnnotation("构造器")
    private Student(String name) {
        this.name = name;
    }

    Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public Student(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    @MyAnnotation("show方法")
    private String show(String nation, int age) {
        System.out.println("我的国籍是：" + nation +", 我的年龄：" + age);
        return nation;
    }

    public String sports(String yd) {
        System.out.println(this.name + " 喜欢的运动是: " + yd);
        return yd;
    }

    @Override
    public void info() throws RuntimeException, IOException {
        System.out.println("我是一个学生");
    }

    @Override
    public int compareTo(String o) {
        return 0;
    }

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


    public static void staticMethod() {
        System.out.println("我是静态方法");
    }
}

1: 获取当前运行类的属性

    /**
     * 获取当前运行类的属性
     */
    @Test
    public void test1() {
        Class<Student> clazz = Student.class;
        //获取类的属性结构：
        //getFields()：此方法只获取当前运行时类及其父类中声明为public访问权限的属性
        Field[] fields = clazz.getFields();

        for (Field field : fields) {
            System.out.println(field);
        }

        System.out.println("----------------------");
      
        //getDeclaredFields():此方法只获取当前运行时类中声明的所有属性,不包含父类的
        Field[] declaredFields = clazz.getDeclaredFields();
        for (Field field : declaredFields) {
            System.out.println(field);
        }

    }

运行结果：
  public int com.reflex.java1.Student.id
  public double com.reflex.java1.Creature.weight
  ----------------------
  public int com.reflex.java1.Student.id
  private java.lang.String com.reflex.java1.Student.name
  int com.reflex.java1.Student.age

2: 获取当前运行时类属性的：权限修饰符，数据类型，变量

    /**
     * 获取当前运行时类属性的：权限修饰符，数据类型，变量
     */
    @Test
    public void test2() {

        Class clazz = Student.class;

        Field[] declaredFields = clazz.getDeclaredFields();
        for (Field field : declaredFields) {
            System.out.println(field);

            //1: 权限修饰符
            int modifiers = field.getModifiers();
            System.out.println("权限修饰符:" + modifiers + "====>>" + Modifier.toString(modifiers));

            //2: 数据类型
            Class type = field.getType();
            System.out.println("数据类型:" + type.getName());

            //3: 属性名
            String name = field.getName();
            System.out.println("属性名:" + name);
          	System.out.println();
        }
        
    }
运行结果：
  public int com.reflex.java1.Student.id
  权限修饰符:1====>>public
  数据类型:int
  属性名:id

  private java.lang.String com.reflex.java1.Student.name
  权限修饰符:2====>>private
  数据类型:java.lang.String
  属性名:name

  int com.reflex.java1.Student.age
  权限修饰符:0====>>
  数据类型:int
  属性名:age