java – 在MongoDB中插入包含集合的对象

假设我在下面定义了2个类(实际上要复杂得多)：

public class Instrument {
    public String name;
    public List<Identifier> identifiers;
}

public class Identifier {
    public String type;
    public String value;
}

因此,一个仪器可以有多个标识符.
现在我有一个List< Instrument>我想存储在名为“乐器”的Mongo系列中.
到目前为止,我找到的唯一方法是通过逐个插入字段来手动创建每个文档(请参阅下面完整工作示例中的getDocFromInstrument方法).这非常麻烦且容易出错,与底层类完全结合.

有没有更好的方法呢？
因为我需要在某个阶段获取信息,所以关于如何“自动”从数据库中重新创建对象的任何想法也是受欢迎的.

有关信息,以下代码的输出是：

{ "_id" : { "$oid" : "4f44db111d8bc98c289b5d82"},"name" : "inst1","identifiers" : [ { "type" : "type1","value" : "inst1_type1"},{ "type" : "type2","value" : "inst1_type2"}]}
{ "_id" : { "$oid" : "4f44db111d8bc98c289b5d83"},"name" : "inst2","value" : "inst2_type1"},"value" : "inst2_type2"}]}

完整代码：

public class TestMongo {

    private final static String IP = "192.168.3.12";
    private final static String DB_NAME = "test";
    private final static int DEFAULT_PORT = 27017;

    public static void main(String[] args) {
        DB db = null;
        try {
            db = new Mongo(IP,DEFAULT_PORT).getDB(DB_NAME);
            insertSomething(db);
            printContent(db);
            cleanDb(db);
        } catch (Exception e) {
            System.out.println(e);
        } finally {
            if (db != null) {
                db.getMongo().close();
            }
        }
    }

    private static void insertSomething(DB db) {
        Identifier idInst1_1 = new Identifier("type1","inst1_type1");
        Identifier idInst1_2 = new Identifier("type2","inst1_type2");
        Identifier idInst2_1 = new Identifier("type1","inst2_type1");
        Identifier idInst2_2 = new Identifier("type2","inst2_type2");

        Instrument inst1 = new Instrument("inst1",Arrays.asList(idInst1_1,idInst1_2));
        Instrument inst2 = new Instrument("inst2",Arrays.asList(idInst2_1,idInst2_2));

        BasicDBObject doc1 = getDocFromInstrument(inst1);
        BasicDBObject doc2 = getDocFromInstrument(inst2);

        DBCollection instrumentsCollection = db.getCollection("instruments");
        instrumentsCollection.insert(doc1);
        instrumentsCollection.insert(doc2);
    }

    private static void printContent(DB db) {
        DBCollection instrumentsCollection = db.getCollection("instruments");
        DBCursor cur = instrumentsCollection.find();

        while(cur.hasNext()) {
            System.out.println(cur.next());
        }
    }

    private static void cleanDb(DB db) {
        db.dropDatabase();
    }

    private static BasicDBObject getDocFromInstrument(Instrument instrument) {
    BasicDBObject instrumentDoc = new BasicDBObject();
    instrumentDoc.put("name",instrument.name);
    List<BasicDBObject> identifiers = new ArrayList<>();
    for (Identifier identifier : instrument.identifiers) {
        BasicDBObject identifierDoc = new BasicDBObject();
        identifierDoc.put("type",identifier.type);
        identifierDoc.put("value",identifier.value);
        identifiers.add(identifierDoc);
    }
    instrumentDoc.put("identifiers",identifiers);
        return instrumentDoc;
    }

    static class Instrument {
        public String name;
        public List<Identifier> identifiers;

        public Instrument(String name,List<Identifier> ids) {
            this.name = name;
            this.identifiers = ids;
        }

    }

    static class Identifier {
        public String type = "";
        public String value = "";

        public Identifier(String type,String values) {
            this.type = type;
            this.value = values;
        }

    }
}