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Spring Boot 高级篇–MongoDB(3):如何新增文档

Spring Boot winrains 来源:一灰灰Blog 12个月前 (11-08) 67次浏览

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

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"}]
------------------------------------------

作者:一灰灰Blog

来源:http://spring.hhui.top/spring-blog/2019/01/24/190124-SpringBoot%E9%AB%98%E7%BA%A7%E7%AF%87MongoDB%E4%B9%8B%E5%A6%82%E4%BD%95%E6%96%B0%E5%A2%9E%E6%96%87%E6%A1%A3/


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