实现思路：将请求的json数据，去除一些可变字段，将key升序排序，拼接成字符串并进行md5加密，再拼接一些用户信息，这样相同的请求参数得到的加密串必然一致，将此字符串作为key，存入redis，设置过期时间为1秒，一般重复提交都是在1000ms以内；
代码部分
import com.alibaba.fastjson.JSONObject; import com.wang.learn.cloudredis.entity.Book; import com.wang.learn.cloudredis.utils.ReqDedupHelper; import org.springframework.data.redis.connection.RedisStringCommands; import org.springframework.data.redis.core.RedisCallback; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.core.types.Expiration; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import javax.annotation.Resource; import javax.validation.Valid; /** * ClassName RedisController * Description * */ @RestController @RequestMapping("/redis") public class RedisController { @Resource private RedisTemplate<String, Object> stringRedisTemplate; @RequestMapping("/repeat") public Object repeat(@RequestBody @Valid Book book){ //用户 String userId= "12345678"; //接口名 String method = "pay"; //计算请求参数摘要，其中剔除里面请求时间的干扰 String dedupMD5 = ReqDedupHelper.dedupParamMD5(JSONObject.toJSONString(book),"time"); String KEY = "dedup:U=" + userId + "M=" + method + "P=" + dedupMD5; // 1000毫秒过期，1000ms内的重复请求会认为重复 long expireTime = 1000; long expireAt = System.currentTimeMillis() + expireTime; String val = "expireAt@" + expireAt; // NOTE:直接SETNX不支持带过期时间，所以设置+过期不是原子操作，极端情况下可能设置了就不过期了，后面相同请求可能会误以为需要去重，所以这里使用底层API，保证SETNX+过期时间是原子操作 Boolean firstSet = stringRedisTemplate.execute( (RedisCallback<Boolean>) connection -> connection.set(KEY.getBytes(), val.getBytes(), Expiration.milliseconds(expireTime), RedisStringCommands.SetOption.SET_IF_ABSENT)); final boolean isConsiderDup; if (firstSet != null && firstSet) { return book; } else { return "订单重复！"; } } }
import com.alibaba.fastjson.JSON; import com.wang.learn.cloudredis.entity.Book; import lombok.extern.slf4j.Slf4j; import javax.xml.bind.DatatypeConverter; import java.security.MessageDigest; import java.util.Arrays; import java.util.List; import java.util.TreeMap; @Slf4j public class ReqDedupHelper { /** * * @param reqJSON 请求的参数，这里通常是JSON * @param excludeKeys 请求参数里面要去除哪些字段再求摘要(如时间戳字段) * @return 去除参数的MD5摘要 */ public static String dedupParamMD5(final String reqJSON, String... excludeKeys) { String decreptParam = reqJSON; TreeMap paramTreeMap = JSON.parseObject(decreptParam, TreeMap.class); if (excludeKeys!=null) { List<String> dedupExcludeKeys = Arrays.asList(excludeKeys); if (!dedupExcludeKeys.isEmpty()) { for (String dedupExcludeKey : dedupExcludeKeys) { if(paramTreeMap.containsKey(dedupExcludeKey)){ paramTreeMap.remove(dedupExcludeKey); } } } } String paramTreeMapJSON = JSON.toJSONString(paramTreeMap); String md5deDupParam = jdkMD5(paramTreeMapJSON); log.debug("md5deDupParam = {}, excludeKeys = {} {}", md5deDupParam, Arrays.deepToString(excludeKeys), paramTreeMapJSON); return md5deDupParam; } private static String jdkMD5(String src) { String res = null; try { MessageDigest messageDigest = MessageDigest.getInstance("MD5"); byte[] mdBytes = messageDigest.digest(src.getBytes()); res = DatatypeConverter.printHexBinary(mdBytes); } catch (Exception e) { log.error("",e); } return res; } public static void main(String[] args) { Book book = new Book(); book.setId(1); book.setCount(2); book.setName("java编程思想"); book.setTime(System.currentTimeMillis()); String key = dedupParamMD5(JSON.toJSONString(book), "time", "456"); System.out.println(key); } }
