spring data mongo使用小记

一、更新并返回更新后的值

Object newVal = mongoTemplate.findAndModify(query, update,
        FindAndModifyOptions.options().returnNew(true), Object.class, collectionName);

二、批量操作

BulkOperations bulkOps = mongoTemplate.bulkOps(BulkOperations.BulkMode.ORDERED, Object.class, collectionName);
Objects.parallelStream().forEach(fieldId -> {
    Criteria criteria = Criteria.where("parentDocColumnId").is("xxxx");
    criteria.and("parentDocColumn.childDocColumn").is("xxx");
    bulkOps.updateOne(Query.query(criteria), update);
});
bulkOps.execute();

三、聚合统计操作

Criteria criteria = Criteria.where("_id").is(id).and("xxx").is(xxx);
GroupOperation groupOperation =  Aggregation.group("groupName1","groupName2").count().as("count");
Aggregation aggregation = Aggregation.newAggregation(Aggregation.match(criteria),groupOperation);
AggregationResults<Map> results = mongoTemplate.aggregate(aggregation, "CollectionName", Map.class);

四、mongodb shell 对子文档简单分页设计

文档结构如下：

{
    "_id" : ObjectId("58ce336652dcaf34e4e240af"),
    "name" : "三年二班",
    "code" : "20170302",
    "students" : [ 
        {
            "id" : 1,
            "name" : "小明",
            "age" : 9
        }, 
        {
            "id" : 2,
            "name" : "小刘",
            "age" : 10
        }, 
        {
            "id" : 3,
            "name" : "小红",
            "age" : 8
        }, 
        {
            "id" : 4,
            "name" : "小王",
            "age" : 9
        }, 
        {
            "id" : 5,
            "name" : "小孙",
            "age" : 11
        }, 
        {
            "id" : 6,
            "name" : "小周",
            "age" : 8
        }, 
        {
            "id" : 7,
            "name" : "小林",
            "age" : 10
        }, 
        {
            "id" : 8,
            "name" : "小龙",
            "age" : 12
        }, 
        {
            "id" : 9,
            "name" : "小曲",
            "age" : 9
        }, 
        {
            "id" : 10,
            "name" : "小金",
            "age" : 7
        }
    ]
}

// 只显示某个字段，并不显示某个字段

db.getCollection('Class').find({},{"students":1,"_id":0})

// 拆分子文档并查询符合条件的记录

db.getCollection('Class').aggregate([{$unwind:"$students"},{$match:{"students.name":"小明","students.age":{"$gt":8}}}])
db.getCollection('Class').aggregate([{$project:{_id:0, students:1}},{$unwind:"$students"},{$match:{"students.name":"小明","students.age":{"$gt":8}}}])

// 分组统计子文档记录数目

db.getCollection('Class').aggregate([{$project:{_id:0, students:1}},{$unwind:"$students"},{$match:{"students.age":{"$gt":8}}},{$group:{_id:null,count:{$sum:1}}}]).pretty()

// 执行自定义函数

db.eval("queryStudentCount(args)")
db.eval("queryStudentList(args,offset,pagesize)")

queryStudentList函数:

function(age,offset,pagesize) {
    //var start = new Date()
       // for(var i=0; i<200000; i++){
       //    db.Class.insert({_id:i,number:i}) 
        //}   
       // var end = new Date()
       // end-start// write your code here
    var obj = db.getCollection('Class').aggregate([{$project:{_id:0, students:1}},{$unwind:"$students"},{$match:{"students.age":{"$gt":age}}},{$skip:offset},{$limit:pagesize},{"$sort":{"age":1}}]).pretty();
    return obj;
}

queryStudentCount函数:

function(age) {
    //var start = new Date()
       // for(var i=0; i<200000; i++){
       //    db.Class.insert({_id:i,number:i}) 
        //}   
       // var end = new Date()
       // end-start// write your code here
    var obj = db.getCollection('Class').aggregate([{$project:{_id:0, students:1}},{$unwind:"$students"},{$match:{"students.age":{"$gt":age}}},{$group:{_id:0,count:{$sum:1}}}]).pretty();
    return obj;
}