Java MongoDB:クエリ文書

Java MongoDB:クエリドキュメント

このチュートリアルでは、コレクションからドキュメントを取得またはクエリする一般的な方法をいくつか示します。

テストデータ

テスト用に5つのダミードキュメントを挿入します。

{ "_id" : { "$oid" : "id"} , "number" : 1 , "name" : "example-1"}
{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "example-2"}
{ "_id" : { "$oid" : "id"} , "number" : 3 , "name" : "example-3"}
{ "_id" : { "$oid" : "id"} , "number" : 4 , "name" : "example-4"}
{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "example-5"}

1. Find()の例

1.1 Get first matched document only.

    DBObject doc = collection.findOne();
    System.out.println(dbObject);

出力

    { "_id" : { "$oid" : "id"} , "number" : 1 , "name" : "example-1"}

1.2 Get all matched documents.

    DBCursor cursor = collection.find();
    while(cursor.hasNext()) {
        System.out.println(cursor.next());
    }

出力

{ "_id" : { "$oid" : "id"} , "number" : 1 , "name" : "example-1"}
{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "example-2"}
{ "_id" : { "$oid" : "id"} , "number" : 3 , "name" : "example-3"}
{ "_id" : { "$oid" : "id"} , "number" : 4 , "name" : "example-4"}
{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "example-5"}

1.3 Get single field from matched document.

    BasicDBObject allQuery = new BasicDBObject();
    BasicDBObject fields = new BasicDBObject();
    fields.put("name", 1);

    DBCursor cursor = collection.find(allQuery, fields);
    while (cursor.hasNext()) {
        System.out.println(cursor.next());
    }

出力

{ "_id" : { "$oid" : "id"} , "name" : "example-1"}
{ "_id" : { "$oid" : "id"} , "name" : "example-2"}
{ "_id" : { "$oid" : "id"} , "name" : "example-3"}
{ "_id" : { "$oid" : "id"} , "name" : "example-4"}
{ "_id" : { "$oid" : "id"} , "name" : "example-5"}

2. Find()と比較

2.1 Get all documents where number = 5.

    BasicDBObject whereQuery = new BasicDBObject();
    whereQuery.put("number", 5);
    DBCursor cursor = collection.find(whereQuery);
    while(cursor.hasNext()) {
        System.out.println(cursor.next());
    }

出力

{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "example-5"}

2.2 $in example – Get documents where number in 2, 4 and 5.

    BasicDBObject inQuery = new BasicDBObject();
    List list = new ArrayList();
    list.add(2);
    list.add(4);
    list.add(5);
    inQuery.put("number", new BasicDBObject("$in", list));
    DBCursor cursor = collection.find(inQuery);
    while(cursor.hasNext()) {
        System.out.println(cursor.next());
    }

出力

{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "example-2"}
{ "_id" : { "$oid" : "id"} , "number" : 4 , "name" : "example-4"}
{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "example-5"}

2.3 $gt $lt example – Get documents where + 5 > number > 2 +.

    BasicDBObject gtQuery = new BasicDBObject();
    gtQuery.put("number", new BasicDBObject("$gt", 2).append("$lt", 5));
    DBCursor cursor = collection.find(gtQuery);
    while(cursor.hasNext()) {
        System.out.println(cursor.next());
    }

出力

{ "_id" : { "$oid" : "id"} , "number" : 3 , "name" : "example-3"}
{ "_id" : { "$oid" : "id"} , "number" : 4 , "name" : "example-4"}

2.4 $ne example – Get documents where + number != 4 +.

    BasicDBObject neQuery = new BasicDBObject();
    neQuery.put("number", new BasicDBObject("$ne", 4));
    DBCursor cursor = collection.find(neQuery);
    while(cursor.hasNext()) {
        System.out.println(cursor.next());
    }

出力

{ "_id" : { "$oid" : "id"} , "number" : 1 , "name" : "example-1"}
{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "example-2"}
{ "_id" : { "$oid" : "id"} , "number" : 3 , "name" : "example-3"}
{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "example-5"}

3. find()およびLogical

3.1 $and example – get documents where number = 2 and name = 'example-2'.

    BasicDBObject andQuery = new BasicDBObject();
    List obj = new ArrayList();
    obj.add(new BasicDBObject("number", 2));
    obj.add(new BasicDBObject("name", "example-2"));
    andQuery.put("$and", obj);

    System.out.println(andQuery.toString());

    DBCursor cursor = collection.find(andQuery);
    while (cursor.hasNext()) {
        System.out.println(cursor.next());
    }

出力

{ "$and" : [ { "number" : 2} , { "name" : "example-2"}]}

{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "example-2"}

4. find()および正規表現

正規表現パターンでドキュメントを検索します。

4.1 $regex example – get documents where name like pattern 'Mky.*-[1-3]', case insensitive.

    BasicDBObject regexQuery = new BasicDBObject();
    regexQuery.put("name",
        new BasicDBObject("$regex", "Mky.*-[1-3]")
        .append("$options", "i"));

    System.out.println(regexQuery.toString());

    DBCursor cursor = collection.find(regexQuery);
    while (cursor.hasNext()) {
        System.out.println(cursor.next());
    }

出力

{ "name" : { "$regex" : "Mky.*-[1-3]" , "$options" : "i"}}

{ "_id" : { "$oid" : "515ad59e3004c89329c7b259"} , "number" : 1 , "name" : "example-1"}
{ "_id" : { "$oid" : "515ad59e3004c89329c7b25a"} , "number" : 2 , "name" : "example-2"}
{ "_id" : { "$oid" : "515ad59e3004c89329c7b25b"} , "number" : 3 , "name" : "example-3"}

There are more…
MongoDBでサポートされているクエリ演算子の完全なセットについては、このMongoDB operator documentationをお読みください。

5. 完全な例

package com.example.core;

import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

/**
 * Java MongoDB : Query document
 *
 * @author example
 *
 */
public class QueryApp {

    public static void insertDummyDocuments(DBCollection collection) {

        List list = new ArrayList();

        Calendar cal = Calendar.getInstance();

        for (int i = 1; i <= 5; i++) {

            BasicDBObject data = new BasicDBObject();
            data.append("number", i);
            data.append("name", "example-" + i);
            // data.append("date", cal.getTime());

            // +1 day
            cal.add(Calendar.DATE, 1);

            list.add(data);

        }

        collection.insert(list);

    }

    public static void main(String[] args) {

    try {

      Mongo mongo = new Mongo("localhost", 27017);
      DB db = mongo.getDB("yourdb");

      // get a single collection
      DBCollection collection = db.getCollection("dummyColl");

      insertDummyDocuments(collection);

      System.out.println("1. Find first matched document");
      DBObject dbObject = collection.findOne();
      System.out.println(dbObject);

      System.out.println("\n1. Find all matched documents");
      DBCursor cursor = collection.find();
      while (cursor.hasNext()) {
        System.out.println(cursor.next());
      }

      System.out.println("\n1. Get 'name' field only");
      BasicDBObject allQuery = new BasicDBObject();
      BasicDBObject fields = new BasicDBObject();
      fields.put("name", 1);

      DBCursor cursor2 = collection.find(allQuery, fields);
      while (cursor2.hasNext()) {
        System.out.println(cursor2.next());
      }

      System.out.println("\n2. Find where number = 5");
      BasicDBObject whereQuery = new BasicDBObject();
      whereQuery.put("number", 5);
      DBCursor cursor3 = collection.find(whereQuery);
      while (cursor3.hasNext()) {
        System.out.println(cursor3.next());
      }

      System.out.println("\n2. Find where number in 2,4 and 5");
      BasicDBObject inQuery = new BasicDBObject();
      List list = new ArrayList();
      list.add(2);
      list.add(4);
      list.add(5);
      inQuery.put("number", new BasicDBObject("$in", list));
      DBCursor cursor4 = collection.find(inQuery);
      while (cursor4.hasNext()) {
        System.out.println(cursor4.next());
      }

      System.out.println("\n2. Find where 5 > number > 2");
      BasicDBObject gtQuery = new BasicDBObject();
      gtQuery.put("number", new BasicDBObject("$gt", 2).append("$lt", 5));
      DBCursor cursor5 = collection.find(gtQuery);
      while (cursor5.hasNext()) {
        System.out.println(cursor5.next());
      }

      System.out.println("\n2. Find where number != 4");
      BasicDBObject neQuery = new BasicDBObject();
      neQuery.put("number", new BasicDBObject("$ne", 4));
      DBCursor cursor6 = collection.find(neQuery);
      while (cursor6.hasNext()) {
        System.out.println(cursor6.next());
      }

      System.out.println("\n3. Find when number = 2 and name = 'example-2' example");
      BasicDBObject andQuery = new BasicDBObject();

      List obj = new ArrayList();
      obj.add(new BasicDBObject("number", 2));
      obj.add(new BasicDBObject("name", "example-2"));
      andQuery.put("$and", obj);

      System.out.println(andQuery.toString());

      DBCursor cursor7 = collection.find(andQuery);
      while (cursor7.hasNext()) {
        System.out.println(cursor7.next());
      }

      System.out.println("\n4. Find where name = 'Mky.*-[1-3]', case sensitive example");
      BasicDBObject regexQuery = new BasicDBObject();
      regexQuery.put("name",
        new BasicDBObject("$regex", "Mky.*-[1-3]")
                    .append("$options", "i"));

      System.out.println(regexQuery.toString());

      DBCursor cursor8 = collection.find(regexQuery);
      while (cursor8.hasNext()) {
        System.out.println(cursor8.next());
      }

      collection.drop();

      System.out.println("Done");

     } catch (UnknownHostException e) {
        e.printStackTrace();
     } catch (MongoException e) {
        e.printStackTrace();
     }

    }
}

完了しました。