有很多关于这个问题的帖子，但似乎没有一个有效，所以可能有些事情已经改变了。
我正在尝试将我的 Android 应用程序连接到位于 mLab 上的 MongoDB 服务器。我正在使用 Mongo Java Drived，当然已经将该库添加到 android studio。
可以启动应用程序，但是当我单击注册按钮时应用程序崩溃。
这是我的代码:
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();
}
}
list 文件中还有 permision.INTERNET。
如有任何帮助，我们将不胜感激!
//编辑 堆栈跟踪:
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.
最佳答案
不幸的是，根据 this StackOverflow post，Mongo Java 驱动程序无法在 Android 上运行，因为 Android 缺少一些 Java 类。 .然而，好心的 StackOverflow 用户已经 fork 了 Mongo Java Driver 并解决了这个问题。您可以在 Github 上查看他们的库版本.
向下滚动到说明并下载最新的 jar 文件。现在，是这个:
接下来，继续并删除 mongo-java-driver 的 build.gradle 依赖项中的行。要删除的行应如下所示:
dependencies {
...
compile 'org.mongodb:mongodb-driver:3.4.2'
...
}
最后，将您下载的 jar 添加到您的应用程序 (guide here)。现在您的代码无需修改即可运行。我能够很好地使用常规的 MongoDB 功能，但我无法让 GridFS 工作。
关于java - 安卓工作室 : connecting to MongoDB server with Mongo Java Driver，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/42708540/
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