网站采集怎么做/品牌推广方案
自定义注解方式防止前端同一时间多次重复提交
一、 前情提要
有这样一个业务，上课的时候老师给表现好的学生送小花花，
每节课都能统计出某个学生收到的花的总数。
按照产品需求，前端点击送花按钮后30秒内是不能再次送花的(信任的基础)
(上课老师送花行为都进行统计了，可见互联网是多么可怕)
二、技术设计
###2.1 库表设计
CREATE TABLE `t_student_flower` (`id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键（自增）',`classroom_id` bigint(20) NOT NULL COMMENT '每堂课的唯一标识',`student_id` bigint(20) NOT NULL COMMENT '学生唯一标识',`flower_num` bigint(20) NOT NULL DEFAULT '0' COMMENT '学生收到的花数量',PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
2.2 业务逻辑
业务逻辑很简单，针对某一堂课的某一个学生，老师第一次送花就新增一条记录，之后老师给这个学生送花就在原有的记录基础上增加送花数量即可。
如果前端能保证一堂课，一个学生，30秒内只能送一次花，这样设计能99.9999%的保证业务没问题
2.3 代码编写
至于创建SpringBoot项目，连接Mybatis 准备在Mybatis篇章写，这里主要点不是这些。
重要是业务逻辑
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.5.4</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.example</groupId><artifactId>student_flower</artifactId><version>0.0.1-SNAPSHOT</version><name>student_flower</name><description>Demo project for Spring Boot</description><properties><java.version>1.8</java.version></properties><dependencies><!--web--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!--mybatis--><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>1.3.2</version></dependency><!--mysql驱动--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope></dependency><!--lombok 一款还不错的副主编程工具--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.16.18</version><scope>provided</scope></dependency><!--测试使用--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>
application.yml
server:# 服务端口配置port: 8888
spring:# 数据源配置datasource:driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf-8&useSSL=falseusername: rootpassword: 123456mybatis:# mapper扫描路径mapper-locations: classpath:mapper/*.xml# 实体类别名映射包路径type-aliases-package: com.example.student_flower.entityconfiguration:# 开启驼峰命名map-underscore-to-camel-case: true
StudentFlowerController
package com.example.student_flower.controller;import com.example.student_flower.service.StudentFlowerService;
import com.sun.istack.internal.NotNull;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;/*** @author 发现更多精彩 关注公众号：木子的昼夜编程* 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作* @create 2021-09-11 10:35*/
@RestController
public class StudentFlowerController {@AutowiredStudentFlowerService studentFlowerService;/**** @param classroomId 教师ID* @param studentId 学生ID*/@GetMapping(value = "/test/sendflower/{classroomId}/{studentId}")public void sendFlower(@NotNull @PathVariable("classroomId") Long classroomId , @NotNull @PathVariable("studentId") Long studentId){studentFlowerService.SendFlower(classroomId,studentId);}
}
StudentFlowerService
package com.example.student_flower.service;import com.example.student_flower.dao.TStudentFlowerMapper;
import com.example.student_flower.entity.TStudentFlower;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;/*** @author 发现更多精彩 关注公众号：木子的昼夜编程* 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作* @create 2021-09-11 10:38*/
@Service
public class StudentFlowerService {@AutowiredTStudentFlowerMapper mapper;public void SendFlower(Long classroomId, Long studentId){TStudentFlower tStudentFlower = mapper.selectByClassroomIdAndStudentId(classroomId, studentId);// 第一次送花 没有记录 新增if (tStudentFlower == null) {TStudentFlower tsf = new TStudentFlower();tsf.setClassroomId(classroomId);tsf.setStudentId(studentId);tsf.setFlowerNum(1);mapper.insert(tsf);} else {// 已经送过花了 原来数量上+1tStudentFlower.setFlowerNum(tStudentFlower.getFlowerNum() + 1);mapper.update(tStudentFlower);}}
}
TStudentFlowerMapper
package com.example.student_flower.dao;import com.example.student_flower.entity.TStudentFlower;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;/*** @author 发现更多精彩 关注公众号：木子的昼夜编程* 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作* @create 2021-09-11 10:14*/
@Mapper
public interface TStudentFlowerMapper {// 插入void insert(TStudentFlower tStudentFlower);// 更新void update(TStudentFlower tStudentFlower);// 查询TStudentFlower selectByClassroomIdAndStudentId(@Param("classroomId") Long classroomId,@Param("studentId") Long studentId);
}TStudentFlowerMapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.example.student_flower.dao.TStudentFlowerMapper"><!--新增--><insert id="insert" parameterType="TStudentFlower">INSERT INTO t_student_flower (classroom_id,student_id,flower_num)VALUES (#{classroomId},#{studentId},#{flowerNum})</insert><!--更新--><update id="update" parameterType="TStudentFlower">UPDATE t_student_flowerSET flower_num = #{flowerNum}WHERE id=#{id};</update><select id="selectByClassroomIdAndStudentId"resultType="TStudentFlower">select * from t_student_flowerwhere classroom_id = #{classroomId} and student_id = #{studentId}</select>
</mapper>
2.4 测试
浏览器直接访问：
http://127.0.0.1:8888/test/sendflower/1/1
就会给classroomId = 1 ,studentId = 1 的学生送一朵花
2.5 问题所在
一切看似没有问题，因为请求频率还没有达到可以出错的速度。
我们写一个测试用了来模拟前端不可信任的时候（由于某种原因他们送花事件绑定了多次没有解绑，也就是同一时间发送多次送花请求）
package com.example.student_flower;import com.example.student_flower.service.StudentFlowerService;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;import java.util.concurrent.TimeUnit;@SpringBootTest
class StudentFlowerApplicationTests {@AutowiredStudentFlowerService service;@Testvoid sendFlower() throws InterruptedException {final Long classroomId = 2L;final Long studengId = 102L;Thread thread1 = new Thread(() -> {service.SendFlower(classroomId, studengId);System.out.println("thread1执行完了");});Thread thread2 = new Thread(() -> {service.SendFlower(classroomId, studengId);System.out.println("thread2执行完了");});Thread thread3 = new Thread(() -> {service.SendFlower(classroomId, studengId);System.out.println("thread3执行完了");});thread1.start();thread2.start();thread3.start();// 睡会儿 等三个线程跑完 很low? 做测试凑活用吧Thread.sleep(TimeUnit.SECONDS.toMillis(20));}}执行完看一下数据库结果：
这肯定是有问题的 多三条要出问题的，要扣钱绩效的
三、解决方案
解决方案有很多，我今天介绍一种自定义注解的方式（其实就是用了分布redis锁）
方案看似很简单：
自定义注解MyAnotation
package com.example.student_flower.common.anotation;import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;/*** @author 发现更多精彩 关注公众号：木子的昼夜编程 分享一个生活在互联网底层做着增删改查的码农的感悟与学习** 关于自定义注解 后边有机会专门写一写 先会用* @create 2021-09-11 15:26*/
@Target({ElementType.METHOD}) // 方法上使用的注解
@Retention(RetentionPolicy.RUNTIME) // 运行时通过反射访问
public @interface MyAnotation {/*** 获取锁时默认等待多久*/int waitTime() default 3;/*** 锁过期时间*/int expireTime() default 20;/*** 锁key值*/String redisKey() default "";/*** 锁key后拼接的动态参数的值*/String[] params() default {};
}
自定义切面处理逻辑，进行放重复提交校验MyAspect
package com.example.student_flower.common.aspect;import com.example.student_flower.common.anotation.MyAnotation;
import com.example.student_flower.util.HttpContextUtils;
import com.example.student_flower.util.SpelUtil;
import io.micrometer.core.instrument.util.StringUtils;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;
import java.util.concurrent.TimeUnit;/*** @author 发现更多精彩 关注公众号：木子的昼夜编程* 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作** 关于spring面向切面的知识 等以后文章有机会我写一写（自己也不太熟 暂时会用）** @create 2021-09-11 15:29*/
@Slf4j
@Aspect
@Component
public class MyAspect {@AutowiredRedissonClient redissonClient;// 这个是那些方法需要被切 -- 被标记注解MyAnotation的方法要被切@Pointcut("@annotation(com.example.student_flower.common.anotation.MyAnotation)")public void whichMethodAspect() {}/*** 切面 执行业务逻辑 在实际业务方法执行前 后 都可以进行一些额外的操作* 切面的好处就是对你不知不觉*/@Around("whichMethodAspect()")public Object around(ProceedingJoinPoint joinPoint) throws Throwable {// 1. 获取注解MethodSignature signature = (MethodSignature) joinPoint.getSignature();Method method = signature.getMethod();MyAnotation myAnotation = method.getAnnotation(MyAnotation.class);// 2. 锁等待时间int waitTime = myAnotation.waitTime();// 2. 锁超时时间 怕万一finally没有被执行到的时候 多长时间自动释放锁（基本不会不执行finnaly 除非那个点机器down了）final int lockSeconds = myAnotation.expireTime();// 3. 特殊业务自定义keyString key = myAnotation.redisKey();// 自定义redisKey是否使用参数String[] params = myAnotation.params();// 4.获取HttpServletRequestHttpServletRequest request = HttpContextUtils.getRequest();if (request == null) {throw new Exception("错误的请求 request为null");}assert request != null;// 5. 组合redis锁key// 5.1 如果没有自定义 用默认的 url+tokenif (StringUtils.isBlank(key) && (params == null || params.length == 0)) {// 这里怎么获取token 主要看自己项目用的什么框架 token在哪个位置存储着String token = request.getHeader("Authorization");String requestURI = request.getRequestURI();key = requestURI+token;} else {// 5.2 自定义keykey = SpelUtil.generateKeyBySpEL(key, params, joinPoint);}// 6. 获取key// 获取锁 获取不到最多等waitTime秒 lockSeconds秒后自动释放锁// 每个项目组应该会有自己的redisUtil的封装 我这里就用最简单的方式// 怎么使用锁不是重点 重点是这个思想RLock lock = redissonClient.getLock(key);log.info("tryLock key = {}", key);boolean b = lock.tryLock(waitTime, lockSeconds, TimeUnit.SECONDS);// 获取锁成功if (b) {try {log.info("tryLock success, key = {}", key);// 7. 执行业务代码 返回结果return joinPoint.proceed();} finally {lock.unlock();}} else {// 获取锁失败log.info("tryLock fail, key = {}", key);throw new Exception("请求频繁，请稍后重试");}}}
Redisson配置RedissonConfig
package com.example.student_flower;import org.redisson.Redisson;
import org.redisson.api.RedissonClient;
import org.redisson.config.Config;
import org.springframework.context.annotation.Bean;/*** @author 发现更多精彩 关注公众号：木子的昼夜编程* 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作* @create 2021-09-11 16:31*/
public class RedissonConfig {// 这里就简单设置 真实项目中会做到配置文件或配置中心@Beanpublic RedissonClient getRedisson() {Config config = new Config();config.useSingleServer().setAddress("redis://127.0.0.1:6379");return Redisson.create(config);}
}获取request对象HttpContextUtils
package com.example.student_flower.util;import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** @author 发现更多精彩 关注公众号：木子的昼夜编程* 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作* @create 2021-09-11 16:17** 获取springboot环境中的request/response对象*/
public class HttpContextUtils {// 获取requestpublic static HttpServletRequest getRequest(){ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();HttpServletRequest request = servletRequestAttributes.getRequest();return request;}// 获取responsepublic static HttpServletResponse getResponse(){ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();HttpServletResponse response = servletRequestAttributes.getResponse();return response;}
}El表达式解析 SpelUtil
package com.example.student_flower.util;import java.lang.reflect.Method;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;/*** @author 发现更多精彩 关注公众号：木子的昼夜编程* 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作* @create 2021-09-11 15:35*//*** EL表达式解析*/
public class SpelUtil {/*** 用于SpEL表达式解析.*/private static SpelExpressionParser parser = new SpelExpressionParser();/*** 用于获取方法参数定义名字.*/private static DefaultParameterNameDiscoverer nameDiscoverer = new DefaultParameterNameDiscoverer();/*** 解析表达式*/public static String generateKeyBySpEL(String key, String[] params, ProceedingJoinPoint joinPoint) {StringBuilder spELString = new StringBuilder();if (params != null && params.length > 0) {spELString.append("'" + key + "'");for (int i = 0; i < params.length; i++) {spELString.append("+#" + params[i]);}} else {return key;}// 通过joinPoint获取被注解方法MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();Method method = methodSignature.getMethod();// 使用spring的DefaultParameterNameDiscoverer获取方法形参名数组String[] paramNames = nameDiscoverer.getParameterNames(method);// 解析过后的Spring表达式对象Expression expression = parser.parseExpression(spELString.toString());// spring的表达式上下文对象EvaluationContext context = new StandardEvaluationContext();// 通过joinPoint获取被注解方法的形参Object[] args = joinPoint.getArgs();// 给上下文赋值for (int i = 0; i < args.length; i++) {context.setVariable(paramNames[i], args[i]);}return expression.getValue(context).toString();}
}controller使用注解：
package com.example.student_flower.controller;import com.example.student_flower.common.anotation.MyAnotation;
import com.example.student_flower.service.StudentFlowerService;
import com.sun.istack.internal.NotNull;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;/*** @author 发现更多精彩 关注公众号：木子的昼夜编程* 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作* @create 2021-09-11 10:35*/
@RestController
public class StudentFlowerController {@AutowiredStudentFlowerService studentFlowerService;/**** @param classroomId 教师ID* @param studentId 学生ID*/@MyAnotation(redisKey = "/test/sendflower", params = {"classroomId", "studentId"})@GetMapping(value = "/test/sendflower/{classroomId}/{studentId}")public void sendFlower(@NotNull @PathVariable("classroomId") Long classroomId , @NotNull @PathVariable("studentId") Long studentId){studentFlowerService.SendFlower(classroomId,studentId);}
}测试类（这里用了MockMvc直接测试controller）
package com.example.student_flower;import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultHandlers;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;import java.util.concurrent.TimeUnit;@SpringBootTest
@AutoConfigureMockMvc
class StudentFlowerTests {@Autowiredprotected MockMvc mockMvc;@Testvoid sendFlower() throws Exception {final Long classroomId = 7L;final Long studengId = 102L;Thread thread1 = new Thread(() -> {try {mockMvc.perform(MockMvcRequestBuilders.get("/test/sendflower/" + classroomId + "/" + studengId).accept(MediaType.APPLICATION_JSON)).andExpect(MockMvcResultMatchers.status().isOk()).andDo(MockMvcResultHandlers.print()).andReturn();} catch (Exception e) {e.printStackTrace();}});Thread thread2 = new Thread(() -> {try {mockMvc.perform(MockMvcRequestBuilders.get("/test/sendflower/" + classroomId + "/" + studengId).accept(MediaType.APPLICATION_JSON)).andExpect(MockMvcResultMatchers.status().isOk()).andDo(MockMvcResultHandlers.print()).andReturn();} catch (Exception e) {e.printStackTrace();}});Thread thread3 = new Thread(() -> {try {mockMvc.perform(MockMvcRequestBuilders.get("/test/sendflower/" + classroomId + "/"+ studengId).accept(MediaType.APPLICATION_JSON)).andExpect(MockMvcResultMatchers.status().isOk()).andDo(MockMvcResultHandlers.print()).andReturn();} catch (Exception e) {e.printStackTrace();}});thread1.start();thread2.start();thread3.start();// 睡会儿 等三个线程跑完 很low? 做测试凑活用吧Thread.sleep(TimeUnit.SECONDS.toMillis(20));}
}去掉controller注解测试 会插入多条，加上MyAnotation注解只会生成一条
四 、唠唠
4.1 项目
主要用到了自定义注解、RedissonClient的redis锁、AOP等知识
可能么有写过这种场景代码的人会觉得比较乱：木有关系全部代码已经提交到github上了，
地址：https://github.com/githubforliming/student_flower
4.2 redis服务
贴心的我把redis的windows免安装包都放到项目里了
test/java/soft 解压 双击redis-server.exe 即可运行
默认没密码
4.3 其他问题
支持参数是对象的自定义key
@MyAnotation(redisKey = "/test/sendflower", params = {"p.id"})@PostMapping(value = "/test/sendflower02")public void sendFlower(@RequestBody Person p){// xxx}