javapojo到org。布森。文件，反之亦然

Question

有没有一种简单的方法可以将简单的POJO转换为org。布森。文件

我知道有这样的方法：

Document doc = new Document();
doc.append("name", person.getName()):

但它是否有一种更简单、打字更少的方式呢

Answer 1

目前，Mongo Java驱动程序3.9.1提供了现成的POJO支持
http://mongodb.github.io/mongo-java-driver/3.9/driver/getting-started/quick-start-pojo/
假设您有这样一个示例集合，其中包含一个嵌套对象

db.createCollection("product", {
validator: {
    $jsonSchema: {
        bsonType: "object",
        required: ["name", "description", "thumb"],
        properties: {
            name: {
                bsonType: "string",
                description: "product - name - string"
            },
            description: {
                bsonType: "string",
                description: "product - description - string"
            },
            thumb: {
                bsonType: "object",
                required: ["width", "height", "url"],
                properties: {
                    width: {
                        bsonType: "int",
                        description: "product - thumb - width"
                    },
                    height: {
                        bsonType: "int",
                        description: "product - thumb - height"
                    },
                    url: {
                        bsonType: "string",
                        description: "product - thumb - url"
                    }
                }
            }

        }
    }
}});

1。为MongoDatabase bean提供适当的CodecRegistry

@Bean
public MongoClient mongoClient() {
    ConnectionString connectionString = new ConnectionString("mongodb://username:password@127.0.0.1:27017/dbname");

    ConnectionPoolSettings connectionPoolSettings = ConnectionPoolSettings.builder()
            .minSize(2)
            .maxSize(20)
            .maxWaitQueueSize(100)
            .maxConnectionIdleTime(60, TimeUnit.SECONDS)
            .maxConnectionLifeTime(300, TimeUnit.SECONDS)
            .build();

    SocketSettings socketSettings = SocketSettings.builder()
            .connectTimeout(5, TimeUnit.SECONDS)
            .readTimeout(5, TimeUnit.SECONDS)
            .build();

    MongoClientSettings clientSettings = MongoClientSettings.builder()
            .applyConnectionString(connectionString)
            .applyToConnectionPoolSettings(builder -> builder.applySettings(connectionPoolSettings))
            .applyToSocketSettings(builder -> builder.applySettings(socketSettings))
            .build();

    return MongoClients.create(clientSettings);
}

@Bean 
public MongoDatabase mongoDatabase(MongoClient mongoClient) {
    CodecRegistry defaultCodecRegistry = MongoClientSettings.getDefaultCodecRegistry();
    CodecRegistry fromProvider = CodecRegistries.fromProviders(PojoCodecProvider.builder().automatic(true).build());
    CodecRegistry pojoCodecRegistry = CodecRegistries.fromRegistries(defaultCodecRegistry, fromProvider);
    return mongoClient.getDatabase("dbname").withCodecRegistry(pojoCodecRegistry);
}

2。为您的POJO添加注释

public class ProductEntity {

    @BsonProperty("name") public final String name;
    @BsonProperty("description") public final String description;
    @BsonProperty("thumb") public final ThumbEntity thumbEntity;

    @BsonCreator
    public ProductEntity(
            @BsonProperty("name") String name,
            @BsonProperty("description") String description,
            @BsonProperty("thumb") ThumbEntity thumbEntity) {
        this.name = name;
        this.description = description;
        this.thumbEntity = thumbEntity;
    }
}

public class ThumbEntity {

    @BsonProperty("width") public final Integer width;
    @BsonProperty("height") public final Integer height;
    @BsonProperty("url") public final String url;

    @BsonCreator
    public ThumbEntity(
            @BsonProperty("width") Integer width,
            @BsonProperty("height") Integer height,
            @BsonProperty("url") String url) {
        this.width = width;
        this.height = height;
        this.url = url;
    }
}

3。查询mongoDB并获取POJO

MongoCollection<Document> collection = mongoDatabase.getCollection("product");
Document query = new Document();
List<ProductEntity> products = collection.find(query, ProductEntity.class).into(new ArrayList<>());

就这样！！！您可以轻松获得您的POJO 没有繁琐的手动映射 并且不丧失运行本机mongo查询的能力

Answer 2

关键是，你不需要把手放在组织上。布森。文件

莫菲娅会在幕后为你做这一切

import com.mongodb.MongoClient;
import org.mongodb.morphia.Datastore;
import org.mongodb.morphia.DatastoreImpl;
import org.mongodb.morphia.Morphia;
import java.net.UnknownHostException;

.....
    private Datastore createDataStore() throws UnknownHostException {
        MongoClient client = new MongoClient("localhost", 27017);
        // create morphia and map classes
        Morphia morphia = new Morphia();
        morphia.map(FooBar.class);
        return new DatastoreImpl(morphia, client, "testmongo");
    }

......

    //with the Datastore from above you can save any mapped class to mongo
    Datastore datastore;
    final FooBar fb = new FooBar("hello", "world");
    datastore.save(fb);

这里有几个例子：https://mongodb.github.io/morphia/

Answer 3

如果将Spring数据MongoDB与springboot结合使用，MongoTemplate有一种方法可以很好地做到这一点

Spring Data MongoDB API

这是一个样品

一,。首先在spring boot项目中自动连接mongoTemplate

@Autowired
MongoTemplate mongoTemplate;

二,。在您的服务中使用mongoTemplate

Document doc = new Document();
mongoTemplate.getConverter().write(person, doc);

为此，需要配置pom文件和yml以注入mongotemplate

波姆。xml

<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-mongodb</artifactId>
    <version>2.1.10.RELEASE</version>
</dependency>

应用程序。yml

# mongodb config
spring:
  data:
    mongodb:
      uri: mongodb://your-mongodb-url

Answer 4

如果您使用的是Morphia，那么可以使用这段代码将POJO转换为文档

Document document = Document.parse( morphia.toDBObject( Entity ).toString() )

如果您没有使用Morphia，那么您可以通过编写自定义映射并将POJO转换为DBObject，然后将DBObject进一步转换为字符串，然后对其进行解析来执行相同的操作

Answer 5

我不知道你的MongoDB版本。但现在，不需要将文档转换为POJO，也不需要将文档转换为POJO。您只需根据需要使用的文档或POJO创建集合，如下所示

//If you want to use Document
MongoCollection<Document> myCollection = db.getCollection("mongoCollection");
Document doc=new Document();
doc.put("name","ABC");
myCollection.insertOne(doc);


//If you want to use POJO
MongoCollection<Pojo> myCollection = db.getCollection("mongoCollection",Pojo.class);
Pojo obj= new Pojo();
obj.setName("ABC");
myCollection.insertOne(obj);

如果要使用POJO，请确保您的Mongo DB配置了正确的codecregistry

MongoClient mongoClient = new MongoClient();
//This registry is required for your Mongo document to POJO conversion
CodecRegistry codecRegistry = fromRegistries(MongoClient.getDefaultCodecRegistry(),
        fromProviders(PojoCodecProvider.builder().automatic(true).build()));
MongoDatabase db = mongoClient.getDatabase("mydb").withCodecRegistry(codecRegistry);

Answer 6

您可以使用Gson和Document.parse(String json)将POJO转换为Document。这适用于java驱动程序的3.4.2版本

大概是这样的：

package com.jacobcs;

import org.bson.Document;

import com.google.gson.Gson;
import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;

public class MongoLabs {

    public static void main(String[] args) {
        // create client and connect to db
        MongoClient mongoClient = new MongoClient("localhost", 27017);
        MongoDatabase database = mongoClient.getDatabase("my_db_name");

        // populate pojo
        MyPOJO myPOJO = new MyPOJO();
        myPOJO.setName("MyName");
        myPOJO.setAge("26");

        // convert pojo to json using Gson and parse using Document.parse()
        Gson gson = new Gson();
        MongoCollection<Document> collection = database.getCollection("my_collection_name");
        Document document = Document.parse(gson.toJson(myPOJO));
        collection.insertOne(document);
    }

}