• SpringBoot 注解开发

    利用自定义注解，解决问题

    例1 自定义注解限制请求

    场景：前端发起的频繁的请求，导致服务器压力过大。需要对后端接口进行限流处理，每个接口都需要做限流处理的话就会导致代码冗余，此时就可以利用注解进行解决

    非注解形式

    这里是用于 某个用户点击的次数（结合radis）进行判断，也可以用请求的ip进行判断

    核心代码：

    1.         //限流,60秒5次
    2.         ValueOperations valueOperations = redisTemplate.opsForValue();
    3.         String uri = request.getRequestURI();
    4.         //captcha = "0"; 这个用于测试
    5.         Integer count =(Integer) valueOperations.get(uri+":"+user.getId());
    6.         if(count == null){
    7.             valueOperations.set(uri+":"+user.getId(),1,60,TimeUnit.SECONDS);
    8.         } else if (count<5) {
    9.             valueOperations.increment(uri+":"+user.getId());
    10.         }else {
    11.             return RespBean.error(RespBeanEnum.ACCESS_LIMIT_REAHCED);
    12.         }

    完整代码：

    1.     @RequestMapping(value = "/path",method = RequestMethod.GET)
    2.     @ResponseBody
    3.     public RespBean getPath(User user,Long goodsId,String captcha,HttpServletRequest request){
    4.         if(user == null){
    5.             return RespBean.error(RespBeanEnum.SESSION_ERROR);
    6.         }
    7.         //限流,60秒5次
    8.         ValueOperations valueOperations = redisTemplate.opsForValue();
    9.         String uri = request.getRequestURI();
    10.         log.info("uri====:{}",uri);
    11.         log.info("qequestIp===={}",request.getRemoteAddr());
    12.         log.info("LocalIp===={}",request.getLocalAddr());
    13.         //captcha = "0";
    14.         Integer count =(Integer) valueOperations.get(uri+":"+user.getId());
    15.         if(count == null){
    16.             valueOperations.set(uri+":"+user.getId(),1,60,TimeUnit.SECONDS);
    17.         } else if (count<5) {
    18.             valueOperations.increment(uri+":"+user.getId());
    19.         }else {
    20.             return RespBean.error(RespBeanEnum.ACCESS_LIMIT_REAHCED);
    21.         }
    22.  
    23.         boolean check= orderService.checkCaptcha(user,goodsId,captcha);
    24.         if(!check){
    25.             return RespBean.error(RespBeanEnum.ERROR_CAPTCHA);
    26.         }
    27.  
    28.         String str = orderService.createPath(user,goodsId);
    29.         return RespBean.success(str);
    30.     }

    注解形式

    注解定义方式，以AcessLimit为例

    1. 定义注解  AccessLimit

    2. 创建拦截器 AccessLimitInterceptor

    3. 在WebConfig 中添加拦截器 addInterceptors

    定义注解AccessLimit
    1. @Retention(RetentionPolicy.RUNTIME)
    2. @Target(ElementType.METHOD)
    3. public @interface AccessLimit {
    4.  
    5.     //时间
    6.     int second();
    7.     //次数
    8.     int maxCount();
    9.  
    10.     //这个用于判断是否需要登录，后续可用SpringSecurity + JWT 实现。
    11.     boolean needLogin() default true;
    12. }
    创建拦截器 AccessLimitInterceptor

    核心代码：

    1. @Component
    2. public class AccessLimitInterceptor implements HandlerInterceptor {
    3.  
    4.     @Autowired
    5.     private RedisTemplate redisTemplate;
    6.  
    7.     @Override
    8.     public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    9.         if(handler instanceof HandlerMethod){
    10.             HandlerMethod hm = (HandlerMethod) handler;
    11.             AccessLimit accessLimit = hm.getMethodAnnotation(AccessLimit.class);
    12.             if( accessLimit ==null){
    13.                 return true;
    14.             }
    15.             int second = accessLimit.second();
    16.             int maxCount = accessLimit.maxCount();
    17.             boolean needLogin = accessLimit.needLogin();
    18.             String key = request.getRequestURI();
    19.            
    20.             ValueOperations valueOperations =redisTemplate.opsForValue();
    21.             Integer count = (Integer) valueOperations.get(key);
    22.             if(count == null){
    23.                 valueOperations.set(key,1,second, TimeUnit.SECONDS);
    24.             } else if (count
    25.                 valueOperations.increment(key);
    26.             } else {
    27.                 render(response,RespBeanEnum.ACCESS_LIMIT_REAHCED);
    28.                 return false;
    29.             }
    30.         }
    31.  
    32.         return true;
    33.     }

    完整代码：

    1. package com.xxx.seckilldemo.annotation;
    2.  
    3.  
    4.  
    5. import com.fasterxml.jackson.databind.ObjectMapper;
    6. import com.xxx.seckilldemo.config.UserContext;
    7. import com.xxx.seckilldemo.pojo.User;
    8. import com.xxx.seckilldemo.service.IUserService;
    9. import com.xxx.seckilldemo.utils.CookieUtil;
    10. import com.xxx.seckilldemo.vo.RespBean;
    11. import com.xxx.seckilldemo.vo.RespBeanEnum;
    12. import org.springframework.beans.factory.annotation.Autowired;
    13. import org.springframework.data.redis.core.RedisTemplate;
    14. import org.springframework.data.redis.core.ValueOperations;
    15. import org.springframework.stereotype.Component;
    16. import org.springframework.util.StringUtils;
    17. import org.springframework.web.method.HandlerMethod;
    18. import org.springframework.web.servlet.HandlerInterceptor;
    19.  
    20. import javax.servlet.http.HttpServletRequest;
    21. import javax.servlet.http.HttpServletResponse;
    22. import java.io.IOException;
    23. import java.io.ObjectInput;
    24. import java.io.PrintWriter;
    25. import java.util.concurrent.TimeUnit;
    26.  
    27. /** 接口限流拦截器
    28.  * @author Adzc
    29.  * @date 2023/11/15 15:40
    30.  */
    31. @Component
    32. public class AccessLimitInterceptor implements HandlerInterceptor {
    33.  
    34.  
    35.     @Autowired
    36.     private IUserService userService;
    37.  
    38.     @Autowired
    39.     private RedisTemplate redisTemplate;
    40.  
    41.     @Override
    42.     public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    43.         if(handler instanceof HandlerMethod){
    44.             User user = getUser(request,response);
    45.             UserContext.setUser(user);
    46.             HandlerMethod hm = (HandlerMethod) handler;
    47.             AccessLimit accessLimit = hm.getMethodAnnotation(AccessLimit.class);
    48.             if( accessLimit ==null){
    49.                 return true;
    50.             }
    51.             int second = accessLimit.second();
    52.             int maxCount = accessLimit.maxCount();
    53.  
    54.             //此处是登录相关
    55.             boolean needLogin = accessLimit.needLogin();
    56.             String key = request.getRequestURI();
    57.             if(needLogin){
    58.                 if (user == null){
    59.                     render(response, RespBeanEnum.SESSION_ERROR);
    60.                     return false;
    61.                 }
    62.                 key+=":"+user.getId();
    63.             }
    64.             
    65.             //在有效时间内，次数的判断
    66.             ValueOperations valueOperations =redisTemplate.opsForValue();
    67.             Integer count = (Integer) valueOperations.get(key);
    68.             if(count == null){
    69.                 valueOperations.set(key,1,second, TimeUnit.SECONDS);
    70.             } else if (count
    71.                 valueOperations.increment(key);
    72.             } else {
    73.                 //返回对象的定义
    74.                 render(response,RespBeanEnum.ACCESS_LIMIT_REAHCED);
    75.                 return false;
    76.             }
    77.         }
    78.  
    79.         return true;
    80.     }
    81.  
    82.     /**
    83.      * 获取当前用户
    84.      * @param request
    85.      * @param response
    86.      * @return
    87.      */
    88.     private User getUser(HttpServletRequest request,HttpServletResponse response){
    89.         String ticket = CookieUtil.getCookieValue(request,"userTicket");
    90.         if (StringUtils.isEmpty(ticket)){
    91.             System.out.println("没有获取到用户");
    92.             return null;
    93.         }
    94.         return userService.getUserByCookie(ticket,request,response);
    95.     }
    96.  
    97.     /**
    98.      * 构建返回对象
    99.      * @param response
    100.      * @param respBeanEnum
    101.      */
    102.     private void render(HttpServletResponse response,RespBeanEnum respBeanEnum) throws IOException {
    103.         response.setContentType("application/json");
    104.         response.setCharacterEncoding("utf-8");
    105.         PrintWriter out = response.getWriter();
    106.         RespBean respBean = RespBean.error(respBeanEnum);
    107.         out.write(new ObjectMapper().writeValueAsString(respBean));
    108.         out.flush();
    109.         out.close();
    110.  
    111.     }
    112. }

    返回对象用到了枚举

    1. /**
    2.  * 公共返回对象
    3.  * @author Adzc
    4.  * @date 2023/9/25 23:19
    5.  */
    6.  
    7. @Data
    8. @AllArgsConstructor
    9. @NoArgsConstructor
    10. @ToString
    11. public class RespBean {
    12.  
    13.     private long code;
    14.     private String message;
    15.     private Object obj;
    16.  
    17.     /**
    18.      * 成功返回结果
    19.      * @return
    20.      */
    21.     public static RespBean success(){
    22.         return new RespBean(RespBeanEnum.SUCCESS.getCode(), RespBeanEnum.SUCCESS.getMessage(),null);
    23.     }
    24.  
    25.     public static RespBean success(Object obj){
    26.         return new RespBean(RespBeanEnum.SUCCESS.getCode(), RespBeanEnum.SUCCESS.getMessage(),obj);
    27.     }
    28.  
    29.     /**
    30.      * 失败返回结果
    31.      * @param respBeanEnum
    32.      * @return
    33.      */
    34.     public static RespBean error(RespBeanEnum respBeanEnum){
    35.         return new RespBean(respBeanEnum.getCode(), respBeanEnum.getMessage(),null);
    36.     }
    37.  
    38.     public static RespBean error(RespBeanEnum respBeanEnum,Object obj){
    39.         return new RespBean(respBeanEnum.getCode(), respBeanEnum.getMessage(),obj);
    40.     }
    41. }
    1. @Getter
    2. @ToString
    3. @AllArgsConstructor
    4. public enum RespBeanEnum {
    5.  
    6.     SUCCESS(200,"SUCCESS"),
    7.     ERROR(500,"服务端异常"),
    8.  
    9.     //登录模块
    10.     LOGIN_ERROR(500210,"用户名或密码不正确"),
    11.     MOBILE_ERROR(500211,"非法手机号"),
    12.     BIND_ERROR(500212,"参数校验异常"),
    13.     MOBILE_NOT_EXIST(500213, "手机号不存在"),
    14.     PASSWORD_UPDATE_FAIL(500214,"密码更新失败"),
    15.     SESSION_ERROR(500215,"用户不存在"),
    16.     ACCESS_LIMIT_REAHCED(500504,"访问过于频繁请稍后在尝试");
    17.     private final Integer code;
    18.  
    19.     private final String message;
    20. }
    在WebConfig 中添加拦截器 addInterceptors

    核心代码

    1.  
    2.     @Override
    3.     public void addInterceptors(InterceptorRegistry registry) {
    4.         registry.addInterceptor(accessLimitInterceptor);
    5.     }
    6.  
    7. }

    完整代码

    1. @Configuration
    2. @EnableWebMvc
    3. public class WebConfig implements WebMvcConfigurer {
    4.  
    5.     @Autowired
    6.     private AccessLimitInterceptor accessLimitInterceptor;
    7.  
    8.  
    9.     @Override
    10.     public void addInterceptors(InterceptorRegistry registry) {
    11.         registry.addInterceptor(accessLimitInterceptor);
    12.     }
    13. }

    例2 利用@JsonSerialize注解+自定义类进行手机号脱敏处理

    场景：很多手机号之类的信息需要在前端页面需要进行脱敏处理

    1. public class PhoneJsonSerializer extends JsonSerializer {
    2.     @Override
    3.     public void serialize(Object value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
    4.         if (value != null && value instanceof String){
    5.             if (!Objects.equals(value,"") && value.toString().length() > 5){
    6.                 String phone = value.toString();
    7.                 phone = phone.substring(0, 3) + "******" + phone.substring(phone.length() - 2);
    8.                 gen.writeString(phone);
    9.             } else {
    10.                 gen.writeObject(value);
    11.             }
    12.         } else {
    13.             gen.writeObject(value);
    14.         }
    15.     }
    16.  
    17. }

    在返回的对象中使用

    1. @JsonSerialize(using = PhoneJsonSerializer.class)
    2.     private String phone;

  • 相关阅读:
    有什么可替代问卷星的好用的问卷工具？
    2022年9月19日--9月25日(ue4热更新视频教程为主，)
    PeLK：101 x 101 的超大卷积网络，同参数量下反超 ViT | CVPR 2024
    通过 SingleFlight 模式学习 Go 并发编程
    防火墙技术：一种保护网络安全的安全模型及其编程实现
    【无标题】
    L61.linux命令每日一练 -- 第九章 Linux进程管理命令 -- renice和nohup
    基于NIFI工具搭建生产级别的IIOT系统
    P1006 [NOIP2008 提高组] 传纸条，棋盘型dp，路径dp
    使用 AJAX 提升网页数据的动态交互
  • 原文地址：https://blog.csdn.net/weixin_53630942/article/details/134496894