spring data mongodb之mongodbTemplate查询总结

ゝ一世哀愁。 2022-06-06 08:13 556阅读 0赞

常用的列表查询（筛选条件，查询字段，排序及分页），相当于关系型数据库的：

select fields from tableName where coditions order by field skip limit;

DBObject cond = new BasicDBObject();
    //等于条件
    cond.put("sex","male");
    //非等于条件
    cond.put("age", new BasicDBObject(QueryOperators.GTE,20)
                .append(QueryOperators.LTE,30));
    //添加or条件（和上面的条件还是and关系）
    BasicDBList orList = new BasicDBList();
    DBObject orCond1 = new BasicDBObject();
    orCond1.put("name", "lisi");
    DBObject orCond2 = new BasicDBObject();
    orCond2.put("name", "zhaoliu");
    orList.add(orCond1);
    orList.add(orCond2);
    cond.put(QueryOperators.OR, orList);
    //限制查询返回的字段
    DBObject feild = new BasicDBObject();
    feild.put("name", 1);//查询name
    feild.put("_id", 0);//_id不查询
    Query query = new BasicQuery(cond,feild);
    //单字段倒序
    query.with(new Sort(Direction.DESC,"age"));
    //多字段排序
    /*List<Order> orders = new ArrayList<Sort.Order>();
    orders.add(new Order(Direction.DESC,"age"));
    orders.add(new Order(Direction.ASC,"name"));
    query.with(new Sort(orders));*/
    //分页
    query.skip(0).limit(10);
    List<HashMap> result = mongoTemplate.find(query, HashMap.class,"person");

QueryOperators常用的比较符：

OR = "$or"：or条件
    AND = "$and"：and条件
    GT = "$gt"：大于操作
    GTE = "$gte"：大于等于操作
    LT = "$lt"：小于操作
    LTE = "$lte"小于等于操作
    NE = "$ne"：不等于操作
    IN = "$in"：in操作
    
    //示例
    BasicDBList fieldList = new BasicDBList();
    fieldList.add("上海");
    cond.put("province", new BasicDBObject(QueryOperators.IN,fieldList));
    
    NIN = "$nin"：not in
    MOD = "$mod";
    
    //示例（age和6取模为0的数据）
    BasicDBList modList = new BasicDBList();
    modList.add(6);
    modList.add(0);
    cond.put("age", new BasicDBObject(QueryOperators.MOD,modList));
    
    ALL = "$all"：字段同时满足all中的所有条件，可以和$elemMatch配合使用
    SIZE = "$size"：数组的长度
    EXISTS = "$exists"：字段是否存在筛选（true,false）
    ELEM_MATCH = "$elemMatch":内嵌文档完全匹配查询
    WHERE = "$where"：where条件，一般用于文档中两个字段的比较
    
    //示例（name字段的值和province的值不等的数据）
    cond.put(QueryOperators.WHERE,"this.name != this.province");
    
    NOR = "$nor"：同时不满足
    TYPE = "$type":字段类型匹配
    //模糊查询
    cond.put("province", new BasicDBObject("$regex","^.*上.*$"));
    NOT = "$not"：不满足指定条件，或者该字段不存在
    ORDER_BY = "$orderby":添加排序字段

这里列出的是比较常用的一些操作符，还有一些比较复杂的（例如计算点一点之间距离条件的）请参考：

使用游标的方式进行分页查询：

DBObject cond = new BasicDBObject();
    //等于条件
    cond.put("sex","male");
    //非等于条件
    cond.put("age", new BasicDBObject(QueryOperators.GTE,20)
                .append(QueryOperators.LTE,30));
    //添加or条件（和上面的条件还是and关系）
    BasicDBList orList = new BasicDBList();
    DBObject orCond1 = new BasicDBObject();
    orCond1.put("name", "lisi");
    DBObject orCond2 = new BasicDBObject();
    orCond2.put("name", "zhaoliu");
    orList.add(orCond1);
    orList.add(orCond2);
    cond.put(QueryOperators.OR, orList);
    //限制查询返回的字段
    DBObject feild = new BasicDBObject();
    feild.put("name", 1);//查询name
    feild.put("_id", 0);//_id不查询
    //排序字段
    DBObject order = new BasicDBObject();
    order.put("age",1);
    DBCursor dbCursor = mongoTemplate.getCollection("person").find(cond, feild).sort(order).skip(0).limit(10);
    System.err.println(dbCursor.count());
    System.err.println(dbCursor.toArray());

根据某字段去重查询：

DBObject cond = new BasicDBObject();
    cond.put("sex","male");
    List distinct = mongoTemplate.getCollection("person").distinct("name",cond);

根据查询条件查询条数：

DBObject cond = new BasicDBObject();
    cond.put("sex","male");
    long count = mongoTemplate.getCollection("person").count(cond);
    System.out.println(count);

使用Aggregation Pipeline进行聚群分析：

List<AggregationOperation> aggregationOptions = new ArrayList<AggregationOperation>(); aggregationOptions.add(Aggregation.match(Criteria.where("province").is("上海"))); aggregationOptions.add(Aggregation.group("age").count().as("count"));
    aggregationOptions.add(Aggregation.project("count").and("age").previousOperation().andExclude("_id"));
    aggregationOptions.add(Aggregation.sort(Direction.DESC,"age"));
    aggregationOptions.add(Aggregation.skip(0L));
    aggregationOptions.add(Aggregation.limit(10));
    Aggregation agg = Aggregation.newAggregation(aggregationOptions);
    AggregationResults<HashMap> aggregate = mongoTemplate.aggregate(agg,"person", HashMap.class);
    List<HashMap> mappedResults = aggregate.getMappedResults();

其中group后可以添加一些聚合函数，如sum，avg等。如果遇到内嵌文档，需要拆分的情况，我们可以使用unwind将内嵌文档进行拆分：

aggregationOptions.add(Aggregation.unwind(field));