POJO 作为 mongodb 中的文档

Question

我正在尝试将实体保存为 Mongodb 中的文档并尝试为其创建编解码器。而且它似乎不起作用。我尝试了 Morphia，但是，我无法找到有关在运行时间使用吗啡将额外字段添加到文档中的文档。这违背了首先使用 Mongodb 的基本目的。我最初希望我的文档在 POJO 中具有固定数量的字段。在运行申请期间，字段数应更改

谁能建议我该怎么做

Answer 1

我不知道这是否是好的解决方案，但这是我所做的。如果您没有为 Mongodb 使用 Morphia。并且您希望您的 POJO 实体被序列化。你可以像下面的代码那样做。但是如果你想组织数据，你必须维护 setters 调用顺序下面是两个 class 给出了一些提示

package com.mongodbtest.entities;

 import java.io.Serializable;

 import org.bson.Document;

 import org.bson.BsonDocument;
 import org.bson.BsonInt32;
  import org.bson.BsonNumber;
 import org.bson.BsonString;

public class User extends BsonDocument {

/**
     * 
     */
private static final long serialVersionUID = -9167404209850672507L;
// private String _id;
private BsonString name;
private BsonString email;
private BsonString address;
private BsonInt32 phno;

public User(String name, String email, StringBuilder address, Number phno) {
    super();
    this.name = new BsonString(name);
    this.email = new BsonString(email);
    this.address = new BsonString(address.toString());
    this.phno = new BsonInt32(phno.intValue());
}

public User() {
}

public BsonString getName() {
    return this.name;
}

public void setName(String name) {
    this.name = new BsonString(name);
    this.append("name", this.name);

}

public BsonString getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = new BsonString(email);
    this.append("email", this.email);
}

public BsonString getAddress() {
    return address;
}

public void setAddress(StringBuilder address) {
    this.address = new BsonString(address.toString());
    this.append("address", this.address);
}

public BsonInt32 getPhno() {
    return phno;
}

public void setPhno(Number phno) {
    this.phno = new BsonInt32(phno.intValue());
    this.append("phno", this.phno);
}

}

和序列化的Class会像这样

package com.mongodb.sample;

import org.bson.BsonDocument;
import org.bson.Document;

import com.mogodbsample.config.DBconfig;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import com.mongodbtest.entities.User;

public class Firstmongoaccess {

public static void main(String... args) {
    MongoDatabase dataase = DBconfig.getdatabase();
    MongoCollection<User> collection = dataase.getCollection("users",  User.class);

    User u1 = new User();
    u1.setAddress(new StringBuilder("something street bangalore 356322"));
    u1.setName("xxxxxx");
    u1.setEmail("gh@gmail.com");
    u1.setPhno(3263433);

    collection.insertOne(u1);
    MongoCursor<? extends BsonDocument> cursor = collection.find().iterator();
    try {
        while (cursor.hasNext()) {
            System.out.println(cursor.next().toJson());
        }
    } finally {
        cursor.close();
    }

}
}

POJO 作为 mongodb 中的文档

POJOs as documents in mongodb

java

entities

annotated-pojos