如何使用拦截器+Redis如何实现接口幂思路详解

import com.yunling.sys.config.exception.ParamValidateException;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Component;
import org.springframework.util.ObjectUtils;
import javax.annotation.Resource;
import java.util.concurrent.TimeUnit;
/**
 * Redis工具类
 *
 * @author 谭永强
 * @date 2023-08-15
 */
@Component
public class RedisUtils {
    @Resource
    private RedisTemplate<String, Object> redisTemplate;
    /**
     * 写入缓存
     *
     * @param key   建
     * @param value 值
     * @return 成功/失败
     */
    public boolean set(final String key, Object value) {
        boolean result = false;
        try {
            ValueOperations<String, Object> operations = redisTemplate.opsForValue();
            operations.set(key, value);
            result = true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
    /**
     * 写入缓存设置时效时间
     *
     * @param key   键
     * @param value 值
     * @return 成功/失败
     */
    public boolean set(final String key, Object value, Long expireTime) {
        boolean result = false;
        try {
            ValueOperations<String, Object> operations = redisTemplate.opsForValue();
            operations.set(key, value);
            redisTemplate.expire(key, expireTime, TimeUnit.SECONDS);
            result = true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
    /**
     * 判断缓存中是否有对应的value
     *
     * @param key 键
     * @return 成功/失败
     */
    public boolean exists(final String key) {
        return Boolean.TRUE.equals(redisTemplate.hasKey(key));
    }
    /**
     * 读取缓存
     *
     * @param key 键
     * @return 成功/失败
     */
    public Object get(final String key) {
        return redisTemplate.opsForValue().get(key);
    }
    /**
     * 删除对应的value
     *
     * @param key 键
     * @return 成功/失败
     */
    public boolean remove(final String key) {
        if (exists(key)) {
            return Boolean.TRUE.equals(redisTemplate.delete(key));
        }
        return false;
    }
    /**
     * 递增
     *
     * @param key   键
     * @param delta 要增加几(大于0)
     * @return 结果
     */
    public Long incr(String key, long delta) {
        if (ObjectUtils.isEmpty(key)) {
            throw new ParamValidateException("key值不能为空");
        }
        if (delta < 0) {
            throw new ParamValidateException("递增因子必须大于0");
        }
        return redisTemplate.opsForValue().increment(key, delta);
    }
    /**
     * 递减
     *
     * @param key   键
     * @param delta 要减少几(小于0)
     * @return 结果
     */
    public Long decr(String key, long delta) {
        if (ObjectUtils.isEmpty(key)) {
            throw new ParamValidateException("key值不能为空");
        }
        if (delta < 0) {
            throw new ParamValidateException("递减因子必须大于0");
        }
        return redisTemplate.opsForValue().increment(key, -delta);
    }
}

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
 * 自动幂等
 * 该注解加在需要幂等的方法上，即可自动上线方法的幂等。
 *
 * @author 谭永强
 * @date 2023-08-15
 */
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface AutoIdempotent {
    /**
     * 限定时间(秒)
     * 限制多少秒内，每个用户只能请求一次该接口。
     */
    long seconds() default 1;
}

import com.alibaba.fastjson.JSON;
import com.alibaba.nacos.common.utils.MD5Utils;
import com.yunling.sys.annotate.AutoIdempotent;
import com.yunling.sys.common.RedisUtils;
import com.yunling.sys.common.ResultData;
import com.yunling.sys.common.ReturnCode;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;
import org.springframework.util.ObjectUtils;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import javax.annotation.Resource;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Objects;
/**
 * 自动幂等拦截器
 *
 * @author 谭永强
 * @date 2023-08-15
 */
@Component
public class AutoIdempotentInterceptor extends HandlerInterceptorAdapter {
    @Resource
    private RedisUtils redisUtils;
    /**
     * @param request  请求
     * @param response 响应
     * @param handler  处理
     * @return 结果
     * @throws Exception 异常
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //判断请求是否为方法的请求
        if (!(handler instanceof HandlerMethod)) {
            return true;
        }
        HandlerMethod method = (HandlerMethod) handler;
        //获取方法中是否有幂等性注解
        AutoIdempotent anno = method.getMethodAnnotation(AutoIdempotent.class);
        //若注解为空则直接返回
        if (Objects.isNull(anno)) {
            return true;
        }
        //限定时间
        long seconds = anno.seconds();
        //token
        String token = request.getHeader(HttpHeaders.AUTHORIZATION);
        if (Objects.isNull(token)) {
            ResultData<String> resultData = ResultData.fail(ReturnCode.ACCESS_DENIED.getCode(), "token不能为空");
            write(response, JSON.toJSONString(resultData));
            return false;
        }
        //此处转MD5的原因就是token长度太长了，转成md5短一些，此操作并不是必须的
        String md5 = MD5Utils.md5Hex(token, StandardCharsets.UTF_8.toString());
        //使用token+method+uri作为key值，此处需要通过key值确定请求的唯一性，也可以使用其他的组合，只要保证唯一性即可
        String key = md5 + ":" + request.getMethod() + ":" + request.getRequestURI();
        Object requestCountObj = redisUtils.get(key);
        if (!ObjectUtils.isEmpty(requestCountObj)) {
            //不为空，说明不是第一次请求，直接报错
            ResultData<String> resultData = ResultData.fail(ReturnCode.RC206.getCode(), "请求已提交，请勿重复请求");
            write(response, JSON.toJSONString(resultData));
            return false;
        }
        //若为空则为第一次请求
        return redisUtils.set(key, 1, seconds);
    }
    /**
     * 返回结果到前端
     *
     * @param response 响应
     * @param body     结果
     * @throws IOException 异常
     */
    private void write(HttpServletResponse response, String body) throws IOException {
        response.setContentType(MediaType.APPLICATION_JSON_VALUE);
        ServletOutputStream os = response.getOutputStream();
        os.write(body.getBytes());
        os.flush();
        os.close();
    }
}

package com.yunling.sys.config;
import com.yunling.sys.config.interceptor.AutoIdempotentInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import javax.annotation.Resource;
/**
 * 将拦截器注入到容器中
 *
 * @author 谭永强
 * @date 2023-08-15
 */
@Configuration
public class WebConfig implements WebMvcConfigurer {
    @Resource
    private AutoIdempotentInterceptor autoIdempotentInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(autoIdempotentInterceptor);
    }
}

@RestController
@RequestMapping("user")
public class SysUserController {
    /**
     * 用户新增
     *
     * @param user 用户信息
     */
    @AutoIdempotent(seconds = 60)
    @PostMapping("add")
    public void add(@RequestBody SysUser user) {
       //业务代码.....
    }
}