通过自定义注解获取日志

1.定义一个注解

package com.hisense.demo02;

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

/**
 * @author : sunkepeng  E-mail : [email protected]
 * @date : 2020/8/8 20:09
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Check {
}

2.写一个测试用类，并使用注解

package com.hisense.demo02;

/**
 * @author : sunkepeng  E-mail : [email protected]
 * @date : 2020/8/8 20:04
 */
public class Calculator {
    @Check
    public void add(){
        System.out.println("1+0=" + (1+0));
    }
    @Check
    public void sub(){
        System.out.println("1-0=" + (1-0));
    }
    @Check
    public void mul(){
        System.out.println("1*0=" + (1*0));
    }
    @Check
    public void div(){
        System.out.println("1/0=" + (1/0));
    }
    public void show(){
        System.out.println("永无bug");
    }
}

3.使用注解，在测试类中输出log

package com.hisense.demo02;

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

/**
 * @author : sunkepeng  E-mail : [email protected]
 * @date : 2020/8/8 21:39
 */
public class TestCheck {
    public static void main(String[] args) throws IOException {
        Calculator calculator = new Calculator();
        Class calculatorClass = calculator.getClass();
        Method[] methods = calculatorClass.getMethods();
        int number =0;
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter("bug.txt"));
        for (Method method : methods) {
            if (method.isAnnotationPresent(Check.class)){
                try {
                    method.invoke(calculator);
                } catch (Exception e) {
                    number++;
                    bufferedWriter.write(method.getName()+"出现异常");
                    bufferedWriter.newLine();
                    bufferedWriter.write("异常的名称："+e.getCause().getClass().getSimpleName());
                    bufferedWriter.newLine();
                    bufferedWriter.write("异常的原因"+e.getCause().getMessage());
                    bufferedWriter.newLine();
                    bufferedWriter.write("-----------------");
                    bufferedWriter.newLine();
                }
            }
        }
        bufferedWriter.write("本次共出现："+number+"次异常");
        bufferedWriter.flush();
        bufferedWriter.close();
    }
}