详解java解决分布式环境中高并发环境下数据插入重复问题

2023-08-25 11:33:05 67

packagecom.nursling.web.filter.context; importcom.nursling.nosql.redis.RedisUtil; importcom.nursling.sign.SignType; importcom.nursling.sign.SignUtil; importredis.clients.jedis.Jedis; importjavax.servlet.ServletRequest; importjavax.servlet.http.HttpServletRequest; importjava.util.HashMap; importjava.util.Map; /** *并发拦截 *高并发下过滤掉相同请求的工具 *@author杨. * */ publicclassContextLJ{ privatestaticfinalIntegerJD=0; /** *上锁使用redis为分布式项目加锁 *@paramsign *@paramtiD *@return *@throwsException */ publicstaticbooleanlock(Stringsign,StringtiD){ synchronized(JD){//加锁 Jedisjedis=RedisUtil.getJedis(); StringuTid=jedis.get(sign); if(uTid==null){ jedis.set(sign,tiD); jedis.expire(sign,36); returntrue; } returnfalse; } } /** *锁验证 *@paramsign *@paramtiD *@return */ publicstaticbooleanchecklock(Stringsign,StringtiD){ Jedisjedis=RedisUtil.getJedis(); StringuTid=jedis.get(sign); returntiD.equals(uTid); } /** *去掉锁 *@paramsign *@paramtiD */ publicstaticvoidclent(Stringsign,StringtiD){ if(checklock(sign,tiD)){ Jedisjedis=RedisUtil.getJedis(); jedis.del(sign); } } /** *获取摘要 *@paramrequest *@return */ publicstaticStringgetSign(ServletRequestrequest){ //此工具是将request中的请求内容拼装成key=value&key=value2的形式源码在线面 Mapmap=SignUtil.getRequstMap((HttpServletRequest)request); Stringsign=null; try{ //这里使用md5方法生成摘要SignUtil.getRequstMap方法源码就不贴了 sign=SignUtil.buildRequest(map,SignType.MD5); }catch(Exceptione){ e.printStackTrace(); } returnsign; } }

publicstaticMapgetRequstMap(HttpServletRequestreq){ Mapparams=newHashMap(); MaprequestParams=req.getParameterMap(); for(Iteratoriter=requestParams.keySet().iterator();iter.hasNext();){ Stringname=(String)iter.next(); String[]values=(String[])requestParams.get(name); StringvalueStr=""; for(inti=0;i

下面是过滤器代码

对分布式锁的利用

packagecom.nursling.web.filter.transaction;

importcom.google.gson.Gson;
importcom.nursling.common.RandomUtil;
importcom.nursling.dao.util.TransactionUtils;
importcom.nursling.model.ApiResult;
importcom.nursling.model.ApiRtnCode;
importcom.nursling.web.filter.context.ContextLJ;
importorg.apache.log4j.Logger;

importjavax.servlet.*;
importjavax.servlet.http.HttpServletResponse;
importjava.io.IOException;

/**
*对事物进行控制并且避免接口直接报漏异常信息
*并且过滤频繁请求
*Createdbyyangchaoon2016/11/4.
*/
publicclassTransactionFilterimplementsFilter{

Loggerlog=Logger.getLogger(this.getClass());

@Override
publicvoidinit(FilterConfigfilterConfig)throwsServletException{
}

@Override
publicvoiddoFilter(ServletRequestrequest,ServletResponsemyResp,FilterChainchain)throwsIOException,ServletException{
Stringsign="sign_"+ContextLJ.getSign(request);//生成摘要
StringtiD=RandomUtil.getRandomString(3)+"_"+Thread.currentThread().getId();//当前线程的身份
try{
if(!ContextLJ.lock(sign,tiD)){
log.warn("放弃相同并发请求"+sign);
frequentlyError(myResp);
return;
}
if(!ContextLJ.checklock(sign,tiD)){
log.warn("加锁验证失败"+sign+""+tiD);
frequentlyError(myResp);
return;
}
chain.doFilter(request,myResp);//放行
}catch(Exceptione){//捕获到异常进行异常过滤
log.error("",e);
retrunErrorInfo(myResp);
}finally{
ContextLJ.clent(sign,tiD);
}
}

/**
*频繁请求
*@parammyResp
*/
privatevoidfrequentlyError(ServletResponsemyResp)throwsIOException{
ApiResult

详解java解决分布式环境中高并发环境下数据插入重复问题

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