Java8进行多个字段分组统计的实例代码

java8进行多个字段分组统计实现代码如下：

// 分组统计
map<string, long> countmap = records.stream().collect(collectors.groupingby(o -> o.getproducttype() + "_" + o.getcountry(), collectors.counting()));
 
list<record> countrecords = countmap.keyset().stream().map(key -> {
  string[] temp = key.split("_");
  string producttype = temp[0];
  string country = temp[1];
   
  record record = new record();
  record.set("device_type", producttype);
  record.set("location", country;
  record.set("count", countmap.get(key).intvalue());
  return record;
}).collect(collectors.tolist());

实例补充：

1.本实例其实可以用一句简单的sql去实现 由于我们项目数据库中时间存的是13位的时间戳 所以必须得转行成日期格式 才能进行分组 如下：

select
    count(1) simplenumber,
    sum(penalty_amount) as simplepenaltyamount,
    handling_department,
    create_time,
left(from_unixtime(left(create_time,10)),7)
from
    t_case_simple_case
where
    1 = 1
group by handling_department,left(from_unixtime(left(create_time,10)),7)

以上的就能实现多字段求和统计等功能 但我们老大考虑到查询速度和换库等问题 建议我不要用from_unixtime（）函数，所以只能用最笨的方法一步步实现 以下是用java8方式实现的 代码如下：

@override
public list<statisticalanalysis> queryfirstcase(string starttime,string condition,string casetype) {
  list<statisticalanalysis> statisticalanalyses = null;
  //简易案件
  if (casetype.equals(casetypeenum.simpletype.code())) {
    statisticalanalyses = statisticalanalysisdao.querysimpledata();
  }
  //一般案件
  if (casetype.equals(casetypeenum.normaltype.code())) {
    statisticalanalyses = statisticalanalysisdao.querynormaldata();
  }
  for (statisticalanalysis analysis : statisticalanalyses) {
    try {
      simpledateformat sdf = new simpledateformat("yyyy-mm");
      string newcreatetime = sdf.format(new date(long.valueof(analysis.getcreatetime())));
      analysis.setcreatetime(newcreatetime);
      sysorg sysorg = commonsearchdao.findbyorgid(analysis.gethandlingdepartment());
      if (sysorg != null) {
        analysis.sethandlingdepartmentname(sysorg.getorgname());
      }
      if(analysis.getsimplepenaltyamount()==null){
        analysis.setsimplepenaltyamount(0.0);
      }
    } catch (exception e) {
      e.printstacktrace();
    }
  }
  list<statisticalanalysis> casetotallist = new arraylist<>();
  //根据部门 日期进行分组 统计
  map<string, map<string, long>> casetotal = statisticalanalyses.stream().collect(collectors.groupingby(statisticalanalysis::getcreatetime, collectors.groupingby(statisticalanalysis::gethandlingdepartmentname, collectors.counting())));
  //根据部门 日期进行分组 求和
  map<string, map<string, double>> sumcase = statisticalanalyses.stream().collect(collectors.groupingby(statisticalanalysis::getcreatetime, collectors.groupingby(statisticalanalysis::gethandlingdepartmentname, collectors.summingdouble(statisticalanalysis::getsimplepenaltyamount))));
  //根据年份进行模糊匹配 取出对应的统计值
  for (map.entry<string, map<string, long>> entry : casetotal.entryset()) {
    if (entry.getkey().indexof(starttime) > -1) {
      statisticalanalysis statisticalanalysis = new statisticalanalysis();
      statisticalanalysis.setcreatetime(entry.getkey());
      //将年份-去掉  组成新的数字  主要作为排序
      string key = entry.getkey().replace("-", "");
      integer sortnum = integer.parseint(key);
      statisticalanalysis.setsortnum(sortnum);
      map<string, long> map = entry.getvalue();
      for (map.entry<string, long> entr : map.entryset()) {
        statisticalanalysis.sethandlingdepartmentname(entr.getkey());
        statisticalanalysis.setsimplenumber(entr.getvalue());
      }
      casetotallist.add(statisticalanalysis);
    }
  }
  casetotallist.sort((a, b) -> a.getsortnum() - b.getsortnum());
  //根据年份进行模糊匹配 取出对应的求和值
  list<statisticalanalysis> analyses = new arraylist<>();
  for (map.entry<string, map<string, double>> entry : sumcase.entryset()) {
    if (entry.getkey().indexof(starttime) > -1) {
      statisticalanalysis statisticalanalysis = new statisticalanalysis();
      statisticalanalysis.setcreatetime(entry.getkey());
      //将年份-去掉  组成新的数字  主要作为排序
      string key = entry.getkey().replace("-", "");
      integer sortnum = integer.parseint(key);
      statisticalanalysis.setsortnum(sortnum);
      map<string, double> map = entry.getvalue();
      for (map.entry<string, double> entr : map.entryset()) {
        statisticalanalysis.sethandlingdepartmentname(entr.getkey());
        statisticalanalysis.setsimplepenaltyamount(entr.getvalue());
      }
      analyses.add(statisticalanalysis);
    }
  }

  analyses.sort((a, b) -> a.getsortnum() - b.getsortnum());
  //将统计和求和组合成一个新的集合返回前端
  list<statisticalanalysis> analysislist = new arraylist<>();
  for (statisticalanalysis analys : casetotallist) {
    for (statisticalanalysis analys2 : analyses) {
      statisticalanalysis statisticalanalysis = new statisticalanalysis();
      if (analys.getsortnum().intvalue() == analys2.getsortnum().intvalue()) {
        statisticalanalysis.setsimplenumber(analys.getsimplenumber());
        statisticalanalysis.setsimplepenaltyamount(analys2.getsimplepenaltyamount());
        statisticalanalysis.setcreatetime(analys.getcreatetime());
        statisticalanalysis.sethandlingdepartmentname(analys.gethandlingdepartmentname());
        analysislist.add(statisticalanalysis);
      }
    }
  }
  list<statisticalanalysis> newanalysislist = new arraylist<>();
  if (analysislist.size() > 0) {
    //查询第一季度
    if (condition.equals(yearenum.first.code())) {
      for (statisticalanalysis analysis : analysislist) {
        statisticalanalysis analysis1 = new statisticalanalysis();
        if (analysis.getcreatetime().indexof(starttime + "-01") > -1) {
          beanutils.copyproperties(analysis, analysis1);
          if(casetype.equals(casetypeenum.simpletype.code())){
            analysis1.settitle(starttime+yearenum.first.desc()+"各部门简易案件");
          }else{
            analysis1.settitle(starttime+yearenum.first.desc()+"各部门一般案件");
          }
          newanalysislist.add(analysis1);
        }
        if (analysis.getcreatetime().indexof(starttime + "-02") > -1) {
          beanutils.copyproperties(analysis, analysis1);
          if(casetype.equals(casetypeenum.simpletype.code())){
            analysis1.settitle(starttime+yearenum.first.desc()+"各部门简易案件");
          }else{
            analysis1.settitle(starttime+yearenum.first.desc()+"各部门一般案件");
          }
          newanalysislist.add(analysis1);
        }
        if (analysis.getcreatetime().indexof(starttime + "-03") > -1) {
          beanutils.copyproperties(analysis, analysis1);
          if(casetype.equals(casetypeenum.simpletype.code())){
            analysis1.settitle(starttime+yearenum.first.desc()+"各部门简易案件");
          }else{
            analysis1.settitle(starttime+yearenum.first.desc()+"各部门一般案件");
          }
          newanalysislist.add(analysis1);
        }
      }
      return newanalysislist;
  }
  //查询第二季度
  if (condition.equals(yearenum.second.code())) {
    for (statisticalanalysis analysis : analysislist) {
      statisticalanalysis analysis1 = new statisticalanalysis();
      if (analysis.getcreatetime().indexof(starttime + "-04") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.second.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.second.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-05") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.second.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.second.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-06") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.second.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.second.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
    }
    return newanalysislist;
  }
  //查询第三季度
  if (condition.equals(yearenum.three.code())) {
    for (statisticalanalysis analysis : analysislist) {
      statisticalanalysis analysis1 = new statisticalanalysis();
      if (analysis.getcreatetime().indexof(starttime + "-07") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.three.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.three.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-08") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.three.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.three.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-09") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.three.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.three.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
    }
    return newanalysislist;
  }
  //查询第四季度
  if (condition.equals(yearenum.four.code())) {
    for (statisticalanalysis analysis : analysislist) {
      statisticalanalysis analysis1 = new statisticalanalysis();
      if (analysis.getcreatetime().indexof(starttime + "-10") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.four.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.four.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-11") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.four.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.four.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-12") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.four.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.four.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
    }
    return newanalysislist;
  }
  //查询上半年 取前六条数据
  if (condition.equals(yearenum.half.code())) {
    for (statisticalanalysis analysis : analysislist) {
      statisticalanalysis analysis1 = new statisticalanalysis();
      if (analysis.getcreatetime().indexof(starttime + "-01") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-02") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-03") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-04") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-05") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-06") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.half.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
    }
    return newanalysislist;
  }
  //查询下半年 后六条数据
  if (condition.equals(yearenum.lasthalf.code())) {
    for (statisticalanalysis analysis : analysislist) {
      statisticalanalysis analysis1 = new statisticalanalysis();
      if (analysis.getcreatetime().indexof(starttime + "-07") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-08") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-09") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-10") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-11") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
      if (analysis.getcreatetime().indexof(starttime + "-12") > -1) {
        beanutils.copyproperties(analysis, analysis1);
        if(casetype.equals(casetypeenum.simpletype.code())){
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门简易案件");
        }else{
          analysis1.settitle(starttime+yearenum.lasthalf.desc()+"各部门一般案件");
        }
        newanalysislist.add(analysis1);
      }
    }
    return newanalysislist;
  }
  if (condition.equals(yearenum.fullyear.code())) {
    for (statisticalanalysis analysis : analysislist) {
      if(casetype.equals(casetypeenum.simpletype.code())){
        analysis.settitle(starttime+yearenum.fullyear.desc()+"各部门简易案件");
      }else{
        analysis.settitle(starttime+yearenum.fullyear.desc()+"各部门一般案件");
      }
    }
    return analysislist;
  }
}
  return null;
}

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