Androidスタジオ：Mongo Java Driverを使用したMongoDBサーバーへの接続

Question

この問題に関する記事はたくさんありますが、誰も問題なく動作しているようです。

私のAndroidアプリケーションをmLabにあるMongoDBサーバに接続しようとしています。私はMongo Java Drivedを使用しています。また、ライブラリをアンドロイドスタジオに追加しました。

アプリを起動することはできますが、[登録]ボタンをクリックするとアプリケーションが実行されます。私はまた、マニフェストファイルでpermision.INTERNETを持って

import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import org.bson.Document; 
import com.mongodb.MongoClient; 
import com.mongodb.MongoClientURI; 
import com.mongodb.client.MongoCollection; 
import com.mongodb.client.MongoDatabase; 

public class MainActivity extends AppCompatActivity { 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    final EditText username = (EditText)findViewById(R.id.username); 
    final Button bRegister = (Button) findViewById(R.id.bRegister); 

    bRegister.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      String stringUsername = username.toString(); 
      try { 
       addToDatabase(stringUsername); 
      } catch(Exception e) { 
       e.printStackTrace(); 
      } 
     } 
    }); 
} 

private static void addToDatabase(String username){ 
    MongoClientURI uri = new MongoClientURI("mongodb:///*mLab database URL */"); 
    MongoClient client = new MongoClient(uri); 
    MongoDatabase db = client.getDatabase(uri.getDatabase()); 
    MongoCollection<Document> coll = db.getCollection("newDB"); 

    Document doc = new Document("username", username); 
    coll.insertOne(doc); 
    client.close(); 
} 
} 

：

は、ここに私のコードです。

ご協力いただければ幸いです。

//編集 スタックトレース：03/10 02:43:09: Launching app Cold swapped changes. $ adb shell am start -n "com.newhdc.pedergb.mongodb_servertester/com.newhdc.pedergb.mongodb_servertester.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER Client not ready yet..Waiting for process to come online Connected to process 4752 on device emulator-5554 D/NetworkSecurityConfig: No Network Security Config specified, using platform default W/org.bson.ObjectId: Failed to get process identifier from JMX, using random number instead java.lang.NoClassDefFoundError: Failed resolution of: Ljava/lang/management/ManagementFactory; at org.bson.types.ObjectId.createProcessIdentifier(ObjectId.java:533) at org.bson.types.ObjectId.<clinit>(ObjectId.java:491) at com.mongodb.connection.ClusterId.<init>(ClusterId.java:47) at com.mongodb.connection.DefaultClusterFactory.create(DefaultClusterFactory.java:105) at com.mongodb.Mongo.createCluster(Mongo.java:744) at com.mongodb.Mongo.createCluster(Mongo.java:728) at com.mongodb.Mongo.createCluster(Mongo.java:702) at com.mongodb.Mongo.<init>(Mongo.java:310) at com.mongodb.Mongo.<init>(Mongo.java:306) at com.mongodb.MongoClient.<init>(MongoClient.java:284) at com.newhdc.pedergb.mongodb_servertester.MainActivity.addToDatabase(MainActivity.java:39) at com.newhdc.pedergb.mongodb_servertester.MainActivity.access$000(MainActivity.java:14) at com.newhdc.pedergb.mongodb_servertester.MainActivity$1.onClick(MainActivity.java:29) at android.view.View.performClick(View.java:5637) at android.view.View$PerformClick.run(View.java:22429) at android.os.Handler.handleCallback(Handler.java:751) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6119) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) Caused by: java.lang.ClassNotFoundException: Didn't find class "java.lang.management.ManagementFactory" on path: DexPathList[[dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-support-annotations-25.1.0_11ac1b6ae4b8623fca16868c12f685674e962f99-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_9-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_8-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_7-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_6-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_5-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_4-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_3-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_2-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_1-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-slice_0-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-mongodb-driver-core-3.4.2_cf1ecbf321a58b8bf97e118b2c0ff7614ac982a5-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-mongodb-driver-3.4.2_cfefe7ed281d321e57736b38e1e68fc6160680ac-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-com.android.support-support-vector-drawable-25.1.0_3dbe341ffa762dac2cc1137bc6aae1731f3bc1c0-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-com.android.support-support-v4-25.1.0_c534a46cb17b55c593319a94e0d90e0b75103a24-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-com.android.support-support-media-compat-25.1.0_b58e3876df91b49420cb0766dd6edfdbff0dedbc-classes.dex", dex file "/data/data/com.newhdc.pedergb.mongodb_servertester/files/instant-run/dex/slice-com.android.support-support-fragment-25.1.0_d616629f11d994c207dfc4b5d01648e3194bccbc-classes.dex", dex f I/cluster: Cluster created with settings {hosts=[ds123080.mlab.com:23080], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500} D/AndroidRuntime: Shutting down VM E/AndroidRuntime: **FATAL EXCEPTION**: main Process: com.newhdc.pedergb.mongodb_servertester, PID: 4752 java.lang.ExceptionInInitializerError at com.mongodb.connection.InternalStreamConnectionFactory.<init>(InternalStreamConnectionFactory.java:41) at com.mongodb.connection.DefaultClusterableServerFactory.create(DefaultClusterableServerFactory.java:68) at com.mongodb.connection.BaseCluster.createServer(BaseCluster.java:360) at com.mongodb.connection.SingleServerCluster.<init>(SingleServerCluster.java:54) at com.mongodb.connection.DefaultClusterFactory.create(DefaultClusterFactory.java:114) at com.mongodb.Mongo.createCluster(Mongo.java:744) at com.mongodb.Mongo.createCluster(Mongo.java:728) at com.mongodb.Mongo.createCluster(Mongo.java:702) at com.mongodb.Mongo.<init>(Mongo.java:310) at com.mongodb.Mongo.<init>(Mongo.java:306) at com.mongodb.MongoClient.<init>(MongoClient.java:284) at com.newhdc.pedergb.mongodb_servertester.MainActivity.addToDatabase(MainActivity.java:39) at com.newhdc.pedergb.mongodb_servertester.MainActivity.access$000(MainActivity.java:14) at com.newhdc.pedergb.mongodb_servertester.MainActivity$1.onClick(MainActivity.java:29) at android.view.View.performClick(View.java:5637) at android.view.View$PerformClick.run(View.java:22429) at android.os.Handler.handleCallback(Handler.java:751) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6119) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.security.CodeSource java.security.ProtectionDomain.getCodeSource()' on a null object reference at com.mongodb.connection.ClientMetadataHelper.getDriverVersion(ClientMetadataHelper.java:111) at com.mongodb.connection.ClientMetadataHelper.getDriverInformation(ClientMetadataHelper.java:201) at com.mongodb.connection.ClientMetadataHelper.addDriverInformation(ClientMetadataHelper.java:182) at com.mongodb.connection.ClientMetadataHelper.<clinit>(ClientMetadataHelper.java:64) at com.mongodb.connection.InternalStreamConnectionFactory.<init>(InternalStreamConnectionFactory.java:41)  at com.mongodb.connection.DefaultClusterableServerFactory.create(DefaultClusterableServerFactory.java:68)  at com.mongodb.connection.BaseCluster.createServer(BaseCluster.java:360)  at com.mongodb.connection.SingleServerCluster.<init>(SingleServerCluster.java:54)  at com.mongodb.connection.DefaultClusterFactory.create(DefaultClusterFactory.java:114)  at com.mongodb.Mongo.createCluster(Mongo.java:744)  at com.mongodb.Mongo.createCluster(Mongo.java:728)  at com.mongodb.Mongo.createCluster(Mongo.java:702)  at com.mongodb.Mongo.<init>(Mongo.java:310)  at com.mongodb.Mongo.<init>(Mongo.java:306)  at com.mongodb.MongoClient.<init>(MongoClient.java:284)  at com.newhdc.pedergb.mongodb_servertester.MainActivity.addToDatabase(MainActivity.java:39)  at com.newhdc.pedergb.mongodb_servertester.MainActivity.access$000(MainActivity.java:14)  at com.newhdc.pedergb.mongodb_servertester.MainActivity$1.onClick(MainActivity.java:29)  at android.view.View.performClick(View.java:5637)  at android.view.View$PerformClick.run(View.java:22429)  at android.os.Handler.handleCallback(Handler.java:751)  at android.os.Handler.dispatchMessage(Handler.java:95)  at android.os.Looper.loop(Looper.java:154)  at android.app.ActivityThread.main(ActivityThread.java:6119)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)  Application terminated.

Answer 1

Androidは、いくつかのJavaクラスが欠落しているよう残念なことに、モンゴJavaドライバはthis StackOverflow postによると、Android上で動作しません。しかし、ある種のStackOverflowユーザーがMongo Java Driverをフォークし、問題を修正しました。ライブラリのバージョンはGithubです。

説明までスクロールし、最新のjarファイルをダウンロードします。今、それはこの1つです：

https://github.com/matfur92/mongo-java-driver/blob/gh-pages/JARs/mongo-java-driver-3.4.0-SNAPSHOT.jar?raw=true。

次に、mongo-java-driverのbuild.gradle依存関係の行を削除してください。最後に、

dependencies { 
    ... 
    compile 'org.mongodb:mongodb-driver:3.4.2' 
    ... 
} 

、あなたのアプリケーション（guide here）にダウンロードjarファイルを追加します。削除する行は次のようになります。これでコードは修正されずに動作します。私は通常のMongoDBの機能をうまく使うことができましたが、GridFSを動作させることができませんでした。

Answer 2

私は同じ問題がありました。 問題は、メインスレッドで接続を呼び出すことです。 onCreateメソッドに以下を追加します。

@Override 
    protected void onCreate(Bundle savedInstanceState) { 
if (android.os.Build.VERSION.SDK_INT > 9) 
     { 
      StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build(); 
      StrictMode.setThreadPolicy(policy); 
     } 

希望します。