实例

用于获取所有带有注解的方法的方法名并记录日到txt中

CheckMethod注解

java">package example.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface CheckMethod {
    String value()default "";
}

Stu类

类中有三个自定义的方法：runAway，eat，cry，其中前两个家里CheckMethod注解

java">package example.reflect.entity;

import example.annotation.AnnoField;
import example.annotation.CheckMethod;
import example.annotation.MyAnno;

@MyAnno(value = "stu_class")
public class Stu {
    @AnnoField(col = "NAME",type = "String")
    private String name;
    @AnnoField(col = "AGE",type = "Number")
    private int age;
    private String id;

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

    public Stu() {
    }

    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 getId() {
        return id;
    }

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

    @CheckMethod()
    public void runAway(){
        System.out.println("run away ...");
    }

    
    @CheckMethod()
    public void eat(String food){
        System.out.println("eat some "+ food);
    }

    public void cry(){
        System.out.println("cry loud ...");
    }

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

测试

java">package example.reflect;

import example.annotation.CheckMethod;
import example.reflect.entity.Stu;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.lang.reflect.Method;

/**
 * 判断注解测试框架，记录到文件txt中
 */
public class DoDemo {
    public static void main(String[] args) throws IOException {
        //记录第几个方法
        int line = 0;
        //文件
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter("D:\\haveAnno.txt"));
        //通过反射获取类
        Class<Stu> stuClass = Stu.class;
        //获取所有的方法
        Method[] methods = stuClass.getMethods();
        for (Method method : methods) {

            line++;
            //判断是否有CheckMethod注解，有则打印名字
            if (method.isAnnotationPresent(CheckMethod.class)) {
                System.out.println(method.getName());
                //记录到文件
                bufferedWriter.write("have Anno: Num :" + line + "CheckMethod!: " + method.getName());
                bufferedWriter.newLine();
            }
        }
        bufferedWriter.flush();
        bufferedWriter.close();
    }
}