3.如何新增文档

本篇博文为mongodb的curd中一篇，前面介绍简单的查询使用，这一篇重点则放在插入数据;

I. 基本使用

首先是准备好基本环境，可以参考博文

• 181213-SpringBoot高级篇MongoDB之基本环境搭建与使用
• 190113-SpringBoot高级篇MongoDB之查询基本使用姿势

1. 新增一条数据

MongoDB一个基本数据称为document，和mysql不一样，没有强制约束哪些字段，可以随意的插入，下面是一个简单的插入演示

private static final String COLLECTION_NAME = "demo";

@Autowired
private MongoTemplate mongoTemplate;

/**
 * 新增一条记录
 */
public void insert() {
    JSONObject object = new JSONObject();
    object.put("name", "一灰灰blog");
    object.put("desc", "欢迎关注一灰灰Blog");
    object.put("age", 28);

    // 插入一条document
    mongoTemplate.insert(object, COLLECTION_NAME);


    JSONObject ans = mongoTemplate
            .findOne(new Query(Criteria.where("name").is("一灰灰blog").and("age").is(28)), JSONObject.class,
                    COLLECTION_NAME);
    System.out.println(ans);
}

使用的关键地方为一行: mongoTemplate.insert(object, COLLECTION_NAME);

• 第一个参数为待插入的document
• 第二个参数为collection name （相当于mysql的table)

执行后输出结果为如下

{"name":"一灰灰blog","_id":{"counter":12472353,"date":1548333180000,"machineIdentifier":14006254,"processIdentifier":17244,"time":1548333180000,"timeSecond":1548333180,"timestamp":1548333180},"age":28,"desc":"欢迎关注一灰灰Blog"}

2. 批量插入

一次插入多条记录，传集合进去即可

/**
 * 批量插入
 */
public void insertMany() {
    List<Map<String, Object>> records = new ArrayList<>();
    for (int i = 0; i < 3; i++) {
        Map<String, Object> record = new HashMap<>(4);
        record.put("wechart", "一灰灰blog");
        record.put("blog", Arrays.asList("http://spring.hhui.top", "http://blog.hhui.top"));
        record.put("nums", 210);
        record.put("t_id", i);
        records.add(record);
    }

    // 批量插入文档
    mongoTemplate.insert(records, COLLECTION_NAME);

    // 查询插入的内容
    List<Map> result =
            mongoTemplate.find(new Query(Criteria.where("wechart").is("一灰灰blog")), Map.class, COLLECTION_NAME);
    System.out.println("Query Insert Records: " + result);
}

返回结果如下:

Query Insert Records: [{t_id=0, wechart=一灰灰blog, _id=5c49b07cd5b7ee435cbe5022, blog=[http://spring.hhui.top, http://blog.hhui.top], nums=210}, {t_id=1, wechart=一灰灰blog, _id=5c49b07cd5b7ee435cbe5023, blog=[http://spring.hhui.top, http://blog.hhui.top], nums=210}, {t_id=2, wechart=一灰灰blog, _id=5c49b07cd5b7ee435cbe5024, blog=[http://spring.hhui.top, http://blog.hhui.top], nums=210}]

3. upsert，不存在才插入

我们希望在插入之前，判断数据是否存在，如果不存在则插入；如果存在则更新；此时就可以采用upsert来使用，一般三个参数

mongoTemplate.upsert(Query query, Update update, String collectionName)

第一个为查询条件，第二个为需要更新的字段，最后一个指定对应的collection，一个简单的实例如下

/**
 * 数据不存在，通过 upsert 新插入一条数据
 *
 * set 表示修改key对应的value
 * addToSet 表示在数组中新增一条
 */
public void upsertNoMatch() {
    // addToSet 表示将数据塞入document的一个数组成员中
    UpdateResult upResult = mongoTemplate.upsert(new Query(Criteria.where("name").is("一灰灰blog").and("age").is(100)),
            new Update().set("age", 120).addToSet("add", "额外增加"), COLLECTION_NAME);
    System.out.println("nomatch upsert return: " + upResult);

    List<JSONObject> re = mongoTemplate
            .find(new Query(Criteria.where("name").is("一灰灰blog").and("age").is(120)), JSONObject.class,
                    COLLECTION_NAME);
    System.out.println("after upsert return should not be null: " + re);
    System.out.println("------------------------------------------");
}

输出结果如下:

nomatch upsert return: AcknowledgedUpdateResult{matchedCount=0, modifiedCount=0, upsertedId=BsonObjectId{value=5c49b07ce6652f7e1add1ea2}}
after upsert return should not be null: [{"add":["额外增加"],"name":"一灰灰blog","_id":{"counter":14491298,"date":1548333180000,"machineIdentifier":15099183,"processIdentifier":32282,"time":1548333180000,"timeSecond":1548333180,"timestamp":1548333180},"age":120}]
------------------------------------------

4. upsert，存在则更新

前面的demo是演示不存在，那么存在数据呢?

/**
 * 只有一条数据匹配，upsert 即表示更新
 */
public void upsertOneMatch() {
    // 数据存在，使用更新
    UpdateResult result = mongoTemplate.upsert(new Query(Criteria.where("name").is("一灰灰blog").and("age").is(120)),
            new Update().set("age", 100), COLLECTION_NAME);
    System.out.println("one match upsert return: " + result);

    List<JSONObject> ans = mongoTemplate
            .find(new Query(Criteria.where("name").is("一灰灰blog").and("age").is(100)), JSONObject.class,
                    COLLECTION_NAME);
    System.out.println("after update return should be one: " + ans);
    System.out.println("------------------------------------------");
}

输出结果如下，注意下面的输出数据的 _id，正视前面插入的那条数据，两个数据唯一的不同，就是age被修改了

one match upsert return: AcknowledgedUpdateResult{matchedCount=1, modifiedCount=1, upsertedId=null}
after update return should be null: [{"add":["额外增加"],"name":"一灰灰blog","_id":{"counter":14491298,"date":1548333180000,"machineIdentifier":15099183,"processIdentifier":32282,"time":1548333180000,"timeSecond":1548333180,"timestamp":1548333180},"age":100}]

5. upsert，多条满足时

如果query条件命中多条数据，怎么办？会修改几条数据呢？

/**
 * 两条数据匹配时，upsert 将只会更新一条数据
 */
public void upsertTwoMatch() {
    // 多条数据满足条件时，只会修改一条数据
    System.out.println("------------------------------------------");
    List<JSONObject> re = mongoTemplate
            .find(new Query(Criteria.where("name").is("一灰灰blog").and("age").in(Arrays.asList(28, 100))),
                    JSONObject.class, COLLECTION_NAME);
    System.out.println("original record: " + re);

    UpdateResult result = mongoTemplate
            .upsert(new Query(Criteria.where("name").is("一灰灰blog").and("age").in(Arrays.asList(28, 100))),
                    new Update().set("age", 120), COLLECTION_NAME);
    System.out.println("two match upsert return: " + result);

    re = mongoTemplate.find(new Query(Criteria.where("name").is("一灰灰blog").and("age").is(120)), JSONObject.class,
            COLLECTION_NAME);
    System.out.println("after upsert return size should be 1: " + re);
    System.out.println("------------------------------------------");
}

根据实际输出进行查看，发现只有一条数据被修改；另外一条保持不变，结果如下

------------------------------------------
original record: [{"name":"一灰灰blog","_id":{"counter":12472353,"date":1548333180000,"machineIdentifier":14006254,"processIdentifier":17244,"time":1548333180000,"timeSecond":1548333180,"timestamp":1548333180},"age":28,"desc":"欢迎关注一灰灰Blog"}, {"add":["额外增加"],"name":"一灰灰blog","_id":{"counter":14491298,"date":1548333180000,"machineIdentifier":15099183,"processIdentifier":32282,"time":1548333180000,"timeSecond":1548333180,"timestamp":1548333180},"age":100}]
two match upsert return: AcknowledgedUpdateResult{matchedCount=1, modifiedCount=1, upsertedId=null}
after upsert return size should be 1: [{"name":"一灰灰blog","_id":{"counter":12472353,"date":1548333180000,"machineIdentifier":14006254,"processIdentifier":17244,"time":1548333180000,"timeSecond":1548333180,"timestamp":1548333180},"age":120,"desc":"欢迎关注一灰灰Blog"}]
------------------------------------------

II. 其他

0. 项目

• 工程：spring-boot-demo
• module: mongo-template

相关博文

• 181213-SpringBoot高级篇MongoDB之基本环境搭建与使用
• 190113-SpringBoot高级篇MongoDB之查询基本使用姿势