java 中mongodb的各种操作查询的实例详解

java 中mongodb的各种操作查询的实例详解

一. 常用查询:

1. 查询一条数据:(多用于保存时判断db中是否已有当前数据,这里 is  精确匹配,模糊匹配 使用regex...)

  public pageurl getbyurl(string url) { 
      return findone(new query(criteria.where("url").is(url)),pageurl.class); 
    } 

2. 查询多条数据:linkurl.id 属于分级查询

  public list<pageurl> getpageurlsbyurl(int begin, int end,string linkurlid) {     
      query query = new query(); 
      query.addcriteria(criteria.where("linkurl.id").is(linkurlid)); 
      return find(query.limit(end - begin).skip(begin), pageurl.class);     
    } 

3.模糊查询:-----关键字---regex

 public long getprocesslandlogscount(list<condition> conditions) 
    { 
      query query = new query(); 
      if (conditions != null && conditions.size() > 0) { 
        for (condition condition : conditions) { 
          query.addcriteria(criteria.where(condition.getkey()).regex(".*?\\" +condition.getvalue().tostring()+ ".*")); 
        } 
      } 
      return count(query, processlandlog.class); 
    } 

最下面，我在代码亲自实践过的模糊查询，只支持字段属性是字符串的查询，你要是查字段属性是int的模糊查询，还真没辙。

4.gte: 大于等于,lte小于等于...注意查询的时候各个字段的类型要和mongodb中数据类型一致

 public list<processlandlog> getprocesslandlogs(int begin,int end,list<condition> conditions,string orderfield,direction direction) 
    { 
      query query = new query(); 
      if (conditions != null && conditions.size() > 0) { 
        for (condition condition : conditions) { 
          if(condition.getkey().equals("time")){ 
            query.addcriteria(criteria.where("time").gte(condition.getvalue())); //gte: 大于等于 
          }else if(condition.getkey().equals("inserttime")){ 
            query.addcriteria(criteria.where("inserttime").gte(condition.getvalue())); 
          }else{ 
            query.addcriteria(criteria.where(condition.getkey()).is(condition.getvalue())); 
          } 
        } 
      } 
      return find(query.limit(end - begin).skip(begin).with(new sort(new sort.order(direction, orderfield))), processlandlog.class); 
    } 
   
  public list<dpsland> getdpslandsbytime(int begin, int end, date begindate,date enddate) { 
   return find(new query(criteria.where("updatetime").gte(begindate).lte(enddate)).limit(end - begin).skip(begin), 
    dpsland.class); 
   } 

查询字段不存在的数据 -----关键字---not

public list<goodsdetail> getgoodsdetails2(int begin, int end) { 
      query query = new query(); 
      query.addcriteria(criteria.where("goodssummary").not()); 
      return find(query.limit(end - begin).skip(begin),goodsdetail.class); 
    } 

查询字段不为空的数据     -----关键字---ne

  criteria.where("key1").ne("").ne(null) 

查询或语句：a || b     ----- 关键字---oroperator

 criteria criteria = new criteria(); 
  criteria.oroperator(criteria.where("key1").is("0"),criteria.where("key1").is(null)); 

查询且语句：a && b     ----- 关键字---and

  criteria criteria = new criteria(); 
  criteria.and("key1").is(false); 
  criteria.and("key2").is(type); 
  query query = new query(criteria); 
  long totalcount = this.mongotemplate.count(query, xxx.class); 

查询一个属性的子属性，例如：查下面数据的key2.keya的语句

  var s = { 
      key1: value1, 
      key2: { 
        keya: valuea, 
        keyb: valueb 
      } 
    }; 
   
  @query("{'key2.keya':?0}") 
  list<asset> findallbykeya(string keya); 

5. 查询数量:----- 关键字---count

 public long getpageinfoscount(list<condition> conditions) { 
      query query = new query(); 
      if (conditions != null && conditions.size() > 0) { 
        for (condition condition : conditions) { 
          query.addcriteria(criteria.where(condition.getkey()).is(condition.getvalue())); 
        } 
      } 
      return count(query, pageinfo.class); 
    } 

查找包含在某个集合范围：----- 关键字---in

  criteria criteria = new criteria(); 
  object [] o = new object[]{0, 1, 2}; //包含所有 
  criteria.and("type").in(o); 
  query query = new query(criteria); 
  query.with(new sort(new sort.order(direction.asc, "type"))).with(new sort(new sort.order(direction.asc, "title"))); 
  list<widgetmonitor> list = this.mongotemplate.find(query, widgetmonitor.class); 

6. 更新一条数据的一个字段:

  public writeresult updatetime(pageurl pageurl) { 
      string id = pageurl.getid(); 
      return updatefirst(new query(criteria.where("id").is(id)),update.update("updatetime", pageurl.getupdatetime()), pageurl.class); 
    } 

7. 更新一条数据的多个字段:

  //调用更新 
  private void updateprocesslandlog(processlandlog processlandlog, 
        int crawlresult) { 
      list<string> fields = new arraylist<string>(); 
      list<object> values = new arraylist<object>(); 
      fields.add("state"); 
      fields.add("result"); 
      fields.add("time"); 
      values.add("1"); 
      values.add(crawlresult); 
      values.add(calendar.getinstance().gettime()); 
      processlandlogreposity.updateprocesslandlog(processlandlog, fields, 
          values); 
    } 
  //更新 
  public void updateprocesslandlog(processlandlog land, list<string> fields,list<object> values) { 
      update update = new update(); 
      int size = fields.size(); 
      for(int i = 0 ; i < size; i++){ 
        string field = fields.get(i); 
        object value = values.get(i); 
        update.set(field, value); 
      } 
      updatefirst(new query(criteria.where("id").is(land.getid())), update,processlandlog.class); 
    } 

8. 删除数据:

  public void deleteobject(class<t> clazz,string id) { 
      remove(new query(criteria.where("id").is(id)),clazz); 
    } 

9.保存数据:

//插入一条数据 
  public void saveobject(object obj) { 
      insert(obj); 
    } 
   
  //插入多条数据   
  public void saveobjects(list<t> objects) { 
      for(t t:objects){ 
        insert(t); 
      } 
    } 

我自己使用的例子：

下面例子涉及到：

精确查询：is；

模糊查询：regex；

分页查询，每页多少：skip，limit

按某个字段排序(或升或降)：new sort(new sort.order(sort.direction.asc, "port"))

查询数量：count

  public map<string, object> getappportdetailbypage(int pageno, int pagesize, string order, string sortby, string appporttype, string appportseachername) { 
    criteria criteria = new criteria(); 
    if (!appporttype.equals("")) { 
      if (!appporttype.equals("all")) { 
        //db表里的字段----appmanagetype 
        //下同 port protocol 也是db表的字段 
        criteria.and("appmanagetype").is(appporttype); 
      } 
    } 
    if (!appportseachername.equals("")) { 
      try { 
        criteria.oroperator(criteria.where("port").is(integer.parseint(appportseachername)), 
            criteria.where("protocol").regex(".*?" + appportseachername + ".*")); 
      }catch (exception e){ 
        criteria.oroperator(criteria.where("protocol").regex(".*?" + appportseachername + ".*")); 
      } 
    } 
    map<string, object> result = maps.newhashmap(); 
    query query = new query(criteria); 
    query.skip((pageno - 1) * pagesize); 
    query.limit(pagesize); 
    if(order != null && sortby != null){ 
      query.with(new sort(new sort.order(order.equals("asc") ? sort.direction.asc : sort.direction.desc, sortby))); 
    }else { 
      query.with(new sort(new sort.order(sort.direction.asc, "port"))); 
    } 
    list<appportmanage> list = this.mongotemplate.find(query, appportmanage.class); 
    long count = this.mongotemplate.count(query, appportmanage.class); 
    result.put("datas", list); 
    result.put("size", count); 
    return result; 
  } 

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