Question

我使用此答案将Android Studio配置为纯java https://stackoverflow.com/a/26196451。然后我开始将Firebase Admin SDK添加到我的项目中我遵循了本教程https://firebase.google.com/docs/admin/setup但是当我运行它时，我得到了这个例外：

Exception in thread "main" java.lang.NoClassDefFoundError: com/google/firebase/FirebaseOptions$Builder
    at com.xwekta.lib.myClass.main(myClass.java:24)
Caused by: java.lang.ClassNotFoundException: com.google.firebase.FirebaseOptions$Builder
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 1 more

来自：

FirebaseOptions options = new FirebaseOptions.Builder()
                .setCredentials(GoogleCredentials.fromStream(serviceAccount))
                .setDatabaseUrl("https://clix-clix6596f.firebaseio.com").build();

然后我转到gradle的缓存文件，找到FirebaseOptions $ Builder.class文件。我将其复制到我应用的classes>java>main>com>xwekta>lib文件夹中。除非我将其名称重命名为不包含$符号的内容，否则Android Studio无法识别它。（顺便说一下包名也是lib）

这是我的代码：

package com.xwekta.lib;

import com.google.api.core.ApiFuture;
import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.firestore.CollectionReference;
import com.google.cloud.firestore.DocumentSnapshot;
import com.google.cloud.firestore.Firestore;
import com.google.cloud.firestore.Query;
import com.google.cloud.firestore.QuerySnapshot;
import com.google.firebase.FirebaseApp;
import com.google.firebase.FirebaseOptions;
import com.google.firebase.cloud.FirestoreClient;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.concurrent.ExecutionException;


public class myClass {
    public static void main(String[] args) throws IOException, ExecutionException, InterruptedException {
        String hi = "Hello World";
        System.out.println(hi);
        FileInputStream serviceAccount = new FileInputStream("D:\\Cem\\Firebasecokonemli\\sirebasea_dmin.json");
        FirebaseOptions options = new FirebaseOptions.Builder()
                .setCredentials(GoogleCredentials.fromStream(serviceAccount))
                .setDatabaseUrl("https://clix-clix-6596f.firebaseio.com").build();
        FirebaseApp.initializeApp(options);
        Firestore fstr = FirestoreClient.getFirestore();
        CollectionReference colref = fstr.collection("users");
        Query query = colref.whereEqualTo("First Name", "Ali");
        ApiFuture<QuerySnapshot> querySnapshot = query.get();
        for (DocumentSnapshot document : querySnapshot.get().getDocuments()) {
            System.out.println(document.getId());
        }

}


}

这是文件层次结构：

|   .gitignore
|   build.gradle
|   lib.iml
|   
+---build
|   +---classes
|   |   \---java
|   |       \---main
|   |           \---com
|   |               \---xwekta
|   |                   \---lib
|   |                           FirebaseOptions$Builder.class // This where I put the file for only troubleshooting.
|   |                           myClass.class
|   |                           
|   +---libs
|   |       lib.jar
|   |       
|   \---tmp
|       +---compileJava
|       \---jar
|               MANIFEST.MF
|               
+---libs
|       
\---src
    \---main
        \---java
            \---com
                \---xwekta
                    \---lib
                            myClass.java

这是build.gradle文件：

apply plugin: 'java-library'

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    api 'com.google.firebase:firebase-admin:5.8.0'
    testCompileOnly 'com.android.support:multidex:1.0.2'
}

sourceCompatibility = "1.7"
targetCompatibility = "1.7"

在Android Studio中的Java / JVM项目中使用Firebase Admin SDK时出现NoClassDefFoundError

0 个答案: