自定义注解 - java文档生成、结合SpringBoot使用

2023-12-26 06:18:03

参考资料：

参考视频

拦截器自定义注解

注：这里仅讲怎么使用，具体原理请参考个人学习笔记?

自定义注解源码介绍：

?其中视频例子2为上述参考视频的例子
视频例子1为原先反射视频的例子

生成JAVA文档：

可以通过javadoc命令生成API文档

首先将要转为文档的类，去掉包名，放在磁盘中

用记事本，notepad++，或者其他工具将编码转化为ANSI编码

在磁盘目录打开CMD,输入以下命令，回车即可生成API文旦

javadoc XXX.java

打开生成的inde.html即可看到API文档

注解的基本结构

注解的基本结构为：

#{元注解}

public??@interface? #{注解名称} {

????????#{属性列表}

}

?注解名称：自定义的注解名称

元注解：用于定义注解的注解，常用的元注解有如下四个：

@Target : ?描述该注解作用范围，即应该标注在java文件的什么上面，常用的值为：

ElementType.Type : 作用于类
ElementType.METHOD: 作用于方法
ElementType.FIELD：作用于字段

????????当然还有其他值可以进行查阅

@Retention：描述注解被保留的阶段，常用的值为：

RetentionPolicy.RUNTIME：当前描述的注解，会保留到class字节码文件中，并被jvm读取到

????????当然还有其他值可以进行查阅

@Documented：描述注解是否被抽取到api文档中,选填，填上就表示参与到API文档中

@Inherited：描述注解是否可以被继承，选填，填上就表示可以被继承

属性列表：注解的属性，需要抽象方法来定义，且必须要有返回值，关于原理下面会讲，这里仅仅讲使用规则

抽象方法必须有返回结果，且返回结果必须是如下类型：

????????①　基本数据类型
????????②　String类型
????????③　枚举类型
????????④　注解
????????⑤　以上类型的数组

属性赋值注意点：

????????下面将结合例子进行说明

如果定义的属性时，使用default关键字给属性默认初始值，可以在使用注解时不赋值；

注解只有一个抽象方法，且抽象方法名为value,那么在使用时可以直接赋值而不去声明value = XXX；

数组赋值的时，使用大括号{}进行包裹，但是如果只有一个值，那么大括号{}可以省略

注解的基本使用方式

下面演示在不结合SpringBoot的情况下，使用自定义注解进行简单的测试

首先自定义一个注解

package com.example.demo.localAnnotation.selfDemo.annoUse;

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

@Target({ElementType.METHOD,ElementType.TYPE,ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface TestAnno {

    String shuXing1() default "zhangsan";

    int shuXing2();

}

然后加在测试的方法上

package com.example.demo.localAnnotation.selfDemo.annoUse;

/**
 * @program: AnnotationDemo
 * @description:
 * @author: wjl
 * @create: 2023-12-04 23:48
 **/
@TestAnno(shuXing2 = 12315)
public class AnnoMethods {

    @TestAnno(shuXing1 = "XXX",shuXing2 = 66)
    private String str = "testShuXing";

    @TestAnno(shuXing2 = 10086)
    public int method01(int a,int b){
        return a+b;
    }

    @TestAnno(shuXing1 = "lisi",shuXing2 = 10010)
    public String method02(String str1,String str2,String str3){
        return str1+"======"+str2+"======"+str3;
    }

    @TestAnno(shuXing1 = "wanglong",shuXing2 = 123456)
    public void method03(){

    }
    
}

然后使用反射进行解析

package com.example.demo.localAnnotation.selfDemo.annoUse;

import org.junit.Test;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * @program: AnnotationDemo
 * @description:
 * @author: wjl
 * @create: 2023-12-05 00:14
 **/
@SuppressWarnings("all")
public class TestAnnoMethods {

    @Test
    public void test01() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        String mathodName = "method01";
        //   一定要创建一个实例
        AnnoMethods methods = new AnnoMethods();
        // 确定执行方法
        Class<?> methodsClass = methods.getClass();
        Class<?>[] classArr = new Class[]{int.class,int.class};
        Method method = methodsClass.getDeclaredMethod(mathodName, classArr);
        // 设置私有方法可达
        method.setAccessible(true);
        // 确定方法的参数
        Object[] valueArr = new Object[]{1,100};
        // 执行方法 和返回值
        Object result = method.invoke(methods, valueArr);
        // 获取 该方法上面的注解 以及相关值
        TestAnno anno = method.getAnnotation(TestAnno.class);
        String shuXing1 = anno.shuXing1();
        int shuXing2 = anno.shuXing2();
        // 遍历进行输出
        System.out.println("下面是获取到的相关值，以及通过反射获取到的结果");
        System.out.println("执行方法为:"+mathodName);
        System.out.println("方法参数为："+valueArr[0]+"******"+valueArr[1]);
        System.out.println("执行结果为："+result);
        System.out.println("注解属性1的值为："+shuXing1);
        System.out.println("注解属性2的值为："+shuXing2);
    }

    @Test
    public void test02() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        String mathodName = "method02";
        //   一定要创建一个实例
        AnnoMethods methods = new AnnoMethods();
        // 确定执行方法
        Class<?> methodsClass = methods.getClass();
        Class<?>[] classArr = new Class[]{String.class,String.class,String.class};
        Method method = methodsClass.getDeclaredMethod(mathodName, classArr);
        // 设置私有方法可达
        method.setAccessible(true);
        // 确定方法的参数
        Object[] valueArr = new Object[]{"peter","wanglili","xuanfeng"};
        // 执行方法 和返回值
        Object result = method.invoke(methods, valueArr);
        // 获取 该方法上面的注解 以及相关值
        TestAnno anno = method.getAnnotation(TestAnno.class);
        String shuXing1 = anno.shuXing1();
        int shuXing2 = anno.shuXing2();
        // 遍历进行输出
        System.out.println("下面是获取到的相关值，以及通过反射获取到的结果");
        System.out.println("执行方法为:"+mathodName);
        System.out.println("方法参数为："+valueArr[0]+"******"+valueArr[1]+"******"+valueArr[2]);
        System.out.println("执行结果为："+result);
        System.out.println("注解属性1的值为："+shuXing1);
        System.out.println("注解属性2的值为："+shuXing2);
    }

    @Test
    public void test03() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        String mathodName = "method03";
        //   一定要创建一个实例
        AnnoMethods methods = new AnnoMethods();
        // 确定执行方法
        Class<?> methodsClass = methods.getClass();
        Class<?>[] classArr = new Class[]{};
        Method method = methodsClass.getDeclaredMethod(mathodName, classArr);
        // 设置私有方法可达
        method.setAccessible(true);
        // 确定方法的参数
        Object[] valueArr = new Object[]{};
        // 执行方法 和返回值
        Object result = method.invoke(methods, valueArr);
        // 获取 该方法上面的注解 以及相关值
        TestAnno anno = method.getAnnotation(TestAnno.class);
        String shuXing1 = anno.shuXing1();
        int shuXing2 = anno.shuXing2();
        // 遍历进行输出
        System.out.println("下面是获取到的相关值，以及通过反射获取到的结果");
        System.out.println("执行方法为:"+mathodName);
        System.out.println("方法参数为：");
        System.out.println("执行结果为："+result);
        System.out.println("注解属性1的值为："+shuXing1);
        System.out.println("注解属性2的值为："+shuXing2);
    }

    @Test
    public void test04(){
        Class<AnnoMethods> methodsClass = AnnoMethods.class;
        TestAnno annotation = methodsClass.getAnnotation(TestAnno.class);
        String shuXing1 = annotation.shuXing1();
        int shuXing2 = annotation.shuXing2();
        System.out.println("类上注解属性1的值为："+shuXing1);
        System.out.println("类上注解属性2的值为："+shuXing2);
    }

    @Test
    public void test05() throws NoSuchFieldException, IllegalAccessException {
        AnnoMethods methods = new AnnoMethods();
        // 确定执行方法
        Class<?> methodsClass = methods.getClass();
        Field field = methodsClass.getDeclaredField("str");
        field.setAccessible(Boolean.TRUE);
        String fieldName = field.getName();
        Object o = field.get(methods);
        TestAnno annotation = field.getAnnotation(TestAnno.class);
        String shuXing1 = annotation.shuXing1();
        int shuXing2 = annotation.shuXing2();
        System.out.println(fieldName);
        System.out.println(o);
        System.out.println(shuXing1);
        System.out.println(shuXing2);

    }

}

AOP+自定义注解：

AOP+自定义注解，是以自定义注解作为切面，进入动态代理，获取到被加注解的类、方法、变量的信息，结合注解的值，进行相关操作，比如：记录日志等；

参考文章?

配置流程如下(具体见本人demo)：

搭建SpringBoot项目，参考
添加依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

?添加自定义注解

package com.example.demo.springAnnotation.AOP;

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 MyLog {
    String upDbName();
}

?添加自定义注解的解析类

package com.example.demo.springAnnotation.AOP;

import com.example.demo.utils.IPAddressUtils;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;
import java.util.Arrays;

/**
 */
@Component
@Aspect
@Slf4j
public class MyLogAspect {

    /**
     *  IP 地址 解析工具类
     */
    @Autowired
    private IPAddressUtils ipAddressUtils;
    /**
     * 只要用到了com.javaxl.p2.annotation.springAop.MyLog这个注解的，就是目标类
     */
    @Pointcut("@annotation(MyLog)")
    private void MyValid() {
    }

/*    @Before("MyValid()")
    public void before(JoinPoint joinPoint) {
        log.info("----------Before开始-----------");
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method method = signature.getMethod();
        String classType = joinPoint.getTarget().getClass().getName();
        MyLog myLog = method.getAnnotation(MyLog.class);
        String desc = myLog.upDbName();
        //获取当前请求request对象
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        log.info("方法名："+ signature.getName());
        log.info("参数值集合："+ Arrays.asList(joinPoint.getArgs()));
        log.info("参数值类型："+ joinPoint.getArgs()[0].getClass().getTypeName());
        log.info("获取目标方法所在类："+ classType);
        log.info("指定注解MyLog的属性值为："+desc);
        log.info("获取URI地址："+request.getRequestURI());
        log.info("获取URL地址："+request.getRequestURL());
        log.info("获取请求方式："+request.getMethod());
        log.info("获取请求的ip地址："+IPAddressUtils.getIpAdrress(request));
        log.info("----------Before结束-----------");

    }*/

/*    @After("MyValid()")
    public void after(JoinPoint joinPoint){
        log.info("后置通知");
    }*/

    @Around("MyValid()")
    public void around(ProceedingJoinPoint joinPoint)throws Throwable {
        log.info("----------Around开始-----------");
        log.info("=========================================================");
        log.info("==========================================================");
        log.info("===你可以根据获取到的信息进行任何操作，比如：进行日志的记录等！！！===");
        log.info("==========================================================");
        log.info("==========================================================");
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method method = signature.getMethod();
        String classType = joinPoint.getTarget().getClass().getName();
        MyLog myLog = method.getAnnotation(MyLog.class);
        String desc = myLog.upDbName();
        //获取当前请求request对象
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        log.info("方法名："+ signature.getName());
        log.info("参数值集合："+ Arrays.asList(joinPoint.getArgs()));
        log.info("参数值类型："+ joinPoint.getArgs()[0].getClass().getTypeName());
        log.info("获取目标方法所在类："+ classType);
        log.info("指定注解MyLog的属性值为："+desc);
        log.info("获取URI地址："+request.getRequestURI());
        log.info("获取URL地址："+request.getRequestURL());
        log.info("获取请求方式："+request.getMethod());
        log.info("获取请求的ip地址："+IPAddressUtils.getIpAdrress(request));
        Object result = joinPoint.proceed();
        log.info("方法的执行结果："+result);
        log.info("----------Around结束-----------");
    }

}

?工具类：IP解析类

package com.example.demo.utils;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;

@Slf4j
@Component
public class IPAddressUtils {
    /**
     * 获取IP地址
     */
    public static String getIpAdrress(HttpServletRequest request) {
        String ipAddress = request.getHeader("X-Forwarded-For");
        if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader("Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getRemoteAddr();
            if ("127.0.0.1".equals(ipAddress) || "0:0:0:0:0:0:0:1".equals(ipAddress)) {
                // 根据网卡取本机配置的IP
                InetAddress inet = null;
                try {
                    inet = InetAddress.getLocalHost();
                } catch (Exception e) {
                    log.error("根据网卡获取本机配置的IP异常=>", e.getMessage());
                }
                if (inet.getHostAddress() != null) {
                    ipAddress = inet.getHostAddress();
                }
            }
        }
        // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
        if (ipAddress != null && ipAddress.length() > 15) {
            if (ipAddress.indexOf(",") > 0) {
                ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
            }
        }
        return ipAddress;
    }

}

添加Service及其实现

package com.example.demo.service;

public interface LogService {
    String test01(String str1,String str2);
    Integer test02(Integer num1,Integer num2);
}

package com.example.demo.service.impl;

import com.example.demo.service.LogService;
import com.example.demo.springAnnotation.AOP.MyLog;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

/**
 * @program: AnnotationDemo
 * @description:
 * @author: wjl
 * @create: 2023-12-13 00:49
 **/
@Service
@Slf4j
public class LogServiceImpl implements LogService {


    @Override
    @MyLog(upDbName = "redis")
    public String test01(String str1, String str2) {
        log.info("进入方法，参数方法分别为： {} ,{}",str1,str2);
        String str = str1+"==="+str2;
        return str;
    }


    @Override
    @MyLog(upDbName = "mysql")
    public Integer test02(Integer num1,Integer num2) {
        log.info("进入方法，参数方法分别为： {} ,{}",num1,num2);
        Integer num = num1+num2;
        return num;
    }
}

?添加Controller

package com.example.demo.controller;

import com.example.demo.service.LogService;
import com.example.demo.springAnnotation.AOP.MyLog;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * @program: AnnotationDemo
 * @description:
 * @author: wjl
 * @create: 2023-12-01 00:02
 **/
@RestController
public class AopController {

    @Autowired
    private LogService logService;

    @RequestMapping("test_01")
    public String testLogAspect01(@RequestParam("str1")String str1,@RequestParam("str2")String str2){
        String str = logService.test01(str1, str2);
        return str;
    }

    @RequestMapping("test_02")
    public Integer testLogAspect02(@RequestParam("num1")Integer num1,@RequestParam("num2")Integer num2){
        Integer num = logService.test02(num1, num2);
        return num;
    }


}

拦截器+自定义注解：

拦截器+自定义注解：拦截器通常是获取链接的入口方法（一半以controller方法为主），然后通过反射获取到方法信息以及相关注解的信息进行相关操作，比如登录验证等

参考文章

配置流程如下(具体见本人demo)：

?搭建SpringBoot项目，参考
自定义注解

package com.example.demo.springAnnotation.INTERCEPT;

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 LoginRequired {

    String userName();

}

配置允许通过的请求和需要拦截的请求

package com.example.demo.springAnnotation.INTERCEPT;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * @program: AnnotationDemo
 * @description:
 * @author: wjl
 * @create: 2023-12-01 10:24
 **/
@Configuration
public class InterceptorTrainConfigurer implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new SourceAccessInterceptor())
                .addPathPatterns("/**")                        //需要拦截 验证的的
                .excludePathPatterns("/test_01","/test_02");   //需要放过的
    }
}

配置拦截的请求，需要进行的操作

package com.example.demo.springAnnotation.INTERCEPT;

import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;

/**
 * @program: AnnotationDemo
 * @description:
 * @author: wjl
 * @create: 2023-12-01 10:21
 **/
public class SourceAccessInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("进入拦截器了");
        // 反射获取方法上的LoginRequred注解
        HandlerMethod handlerMethod = (HandlerMethod) handler;
        Method method = handlerMethod.getMethod();
        LoginRequired loginRequired = method.getAnnotation(LoginRequired.class);
        if (loginRequired == null) {
            return true;
        }
        // 有LoginRequired注解说明需要登录，提示用户登录
        String userName = loginRequired.userName();
        response.setContentType("application/json; charset=utf-8");
        response.getWriter().println("你访问的资源需要登录");
        response.getWriter().println("注解的属性名为："+userName);
        response.getWriter().println("访问的方法名为："+method.getName());
        response.getWriter().println("返回的类型为："+method.getReturnType().getName());
        response.getWriter().println("=========================================================");
        response.getWriter().println("=========================================================");
        response.getWriter().println("=====拦截器同样可以获取到各种属性，根据自身需要进行调用=============");
        response.getWriter().println("=========================================================");
        response.getWriter().println("=========================================================");
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    }
}

配置Controller请求

package com.example.demo.controller;

import com.example.demo.springAnnotation.INTERCEPT.LoginRequired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @program: AnnotationDemo
 * @description:
 * @author: wjl
 * @create: 2023-12-01 10:15
 **/
@RestController
public class InterceptController {

    @GetMapping("/sourceA")
    public String sourceA(){
        return "你正在访问sourceA资源";
    }

    @GetMapping("/sourceB")
    @LoginRequired(userName = "peter")
    public String sourceB(){
        return "你正在访问sourceB资源";
    }

}

文章来源:https://blog.csdn.net/qq_23095607/article/details/135178934
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