Question

//get the collection
DBCollection coll = MongoDBClient.getInstance().getAlarmInfoCollection();

DBObject query = new BasicDBObject();
query.put(aa, "51d2b09f81b8a943f9e825aa");

DBObject update = new BasicDBObject();
DBObject history = new BasicDBObject();
history.put("ishistory", 1);
history.put("acknowledged", 1);
history.put("state", 1);        
update.put("$set", history);
coll.updateMulti(query, update);

之前使用程序更新mongodb中的文档，但有时它可以成功，有时它只更新两个字段（字段，“状态”，不更新），并且propram没有报告任何错误。我的课程有什么错误吗？

Answer 1

我编写了一个单元测试来展示代码的行为方式。该单元测试证明：

您应该能够一次更新多个字段（即可以使用$ set关键字更新多个字段）
updateMulti将更新所有匹配的文档

（注意，像所有Java MongoDB测试一样，它使用TestNG而不是JUnit，但在这种情况下它非常相似）

@Test
public void shouldUpdateAllMatchingFieldsUsingMultiUpdate() throws UnknownHostException {
    MongoClient mongoClient = new MongoClient();
    DB db = mongoClient.getDB("myDatabase");
    DBCollection coll = db.getCollection("coll");
    coll.drop();

    //Put some test data in the database
    for (int i = 0; i < 5; i++) {
        DBObject value = new BasicDBObject();
        value.put("fieldToQuery", "a");
        value.put("ishistory", 2+i);
        value.put("acknowledged", 3+i);
        value.put("state", 14+i);
        value.put("someOtherArbitraryField", Math.random() * 1000);
        System.out.println(value);
        coll.insert(value);
    }

    DBObject query = new BasicDBObject("fieldToQuery", "a");

    DBObject history = new BasicDBObject().append("ishistory", 1)
                                          .append("acknowledged", 1)
                                          .append("state", 1);

    DBObject update = new BasicDBObject("$set", history);

    //This syntax for update means that all three fields will be set to the new given value
    Assert.assertEquals(update.toString(), "{ \"$set\" : { \"ishistory\" : 1 , \"acknowledged\" : 1 , \"state\" : 1}}");

    //Do the update, updating every document that matches the query
    coll.updateMulti(query, update);

    //find The new values
    DBCursor updatedDocuments = coll.find(query);
    for (DBObject updatedDocument : updatedDocuments) {
        Assert.assertEquals(updatedDocument.get("ishistory"), 1);
        Assert.assertEquals(updatedDocument.get("acknowledged"), 1);
        Assert.assertEquals(updatedDocument.get("state"), 1);
        System.out.println(updatedDocument);
    }
}

此测试通过。对于示例运行，数据库中的数据为：

{ "fieldToQuery" : "a" , "ishistory" : 2 , "acknowledged" : 3 , "state" : 14 , "someOtherArbitraryField" : 700.7831275035031}
{ "fieldToQuery" : "a" , "ishistory" : 3 , "acknowledged" : 4 , "state" : 15 , "someOtherArbitraryField" : 72.65538582882736}
{ "fieldToQuery" : "a" , "ishistory" : 4 , "acknowledged" : 5 , "state" : 16 , "someOtherArbitraryField" : 980.0065367659304}
{ "fieldToQuery" : "a" , "ishistory" : 5 , "acknowledged" : 6 , "state" : 17 , "someOtherArbitraryField" : 91.58266286854722}
{ "fieldToQuery" : "a" , "ishistory" : 6 , "acknowledged" : 7 , "state" : 18 , "someOtherArbitraryField" : 448.19176202797115}

在测试结束时，在使用$ set运算符调用updateMulti之后，数据库中的文档为：

{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 700.7831275035031}
{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 72.65538582882736}
{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 980.0065367659304}
{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 91.58266286854722}
{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 448.19176202797115}

因此更新已经奏效，将所有匹配文档的三个字段设置为1，而不接触文档中的任何其他数据。

值得注意的是，我设置查询，更新和历史记录的语法更具可读性和更短，尽管它应该与原始问题中的代码做同样的事情：

DBObject query = new BasicDBObject("fieldToQuery", "a");

DBObject history = new BasicDBObject().append("ishistory", 1)
                                      .append("acknowledged", 1)
                                      .append("state", 1);

DBObject update = new BasicDBObject("$set", history);

我是否认为您希望所有与query匹配的记录都使用给定值更新？因此你使用updateMulti？

MongoDB，使用java同时更新三个文件字段，有时只更新两个字段

1 个答案: