如何修复java.lang.NoClassDefFoundError

Question

大家好，我的代码中我正在创建一个新对象 com.google.api.client.json.JsonFactory as

 final static JsonFactory JSON_FACTORY = new JacksonFactory();

当我在调试模式下运行程序时，执行此行后。编译器给出了一个异常，即

    run:
java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonFactory
    at com.google.api.client.json.jackson2.JacksonFactory.<init>(JacksonFactory.java:45)
    at googleauthtest.GoogleAuthTest.<clinit>(GoogleAuthTest.java:25)
Caused by: java.lang.ClassNotFoundException: com.fasterxml.jackson.core.JsonFactory
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
    ... 2 more
Exception in thread "main" Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

如何解决这个问题？预先感谢

以上问题已修复。现在我陷入了另一个问题，我知道这些问题是由于版本不兼容造成的。那么谁能告诉我他们将 YouTube 数据 API V3 与 java 包装器集成的依赖项是什么。我正在使用服务帐户进行身份验证。

下面是我的java代码..

package googleauthtest;

import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.services.youtube.YouTube;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class Authentication {

   final static HttpTransport TRANSPORT = new NetHttpTransport();
   final static JsonFactory JSON_FACTORY = new JacksonFactory();

   com.google.api.client.googleapis.services.json.AbstractGoogleJsonClient h;
   public static void main(String []g) throws Exception
   {
      List<String>scops = new <String>ArrayList();
      scops.add("https://www.googleapis.com/auth/youtube");

      GoogleCredential credential = null;
      try
      {
         credential = new GoogleCredential.Builder()
        .setTransport(TRANSPORT)
        .setJsonFactory(JSON_FACTORY)
        .setServiceAccountId(Constants.SERVICE_ACCOUNT_ID)
        .setServiceAccountScopes(scops)
        .setServiceAccountPrivateKeyFromP12File(new File("*****/GoogleAuthTest/src/googleauthtest/key.p12"))
        //.setClientSecrets("74279030240-db333th3oph219blk19kkh540m0gu4f5.apps.googleusercontent.com","")
        //.setClientSecrets(GoogleClientSecrets.load(JSON_FACTORY,new InputStreamReader(java.io.Reader.class.getResourceAsStream("client_secrets.json"))))
        .build();

        credential.refreshToken();
        System.out.println(credential.getAccessToken());
        System.out.println(credential.getTokenServerEncodedUrl());
        System.out.println(credential.getExpiresInSeconds());
        System.out.println(credential.getServiceAccountPrivateKey().toString());
        //credential.getServiceAccountPrivateKey();

        YouTube youtube = new YouTube.Builder(TRANSPORT, JSON_FACTORY, credential).setApplicationName("").build();
      }
      catch(IOException e)
      {
          System.out.println(e.toString());
      }

   }
}

新的错误控制台..

Exception in thread "main" java.lang.NoSuchMethodError: com.google.api.client.googleapis.services.json.AbstractGoogleJsonClient.<init>(Lcom/google/api/client/http/HttpTransport;Lcom/google/api/client/http/HttpRequestInitializer;Ljava/lang/String;Ljava/lang/String;Lcom/google/api/client/json/JsonObjectParser;Lcom/google/api/client/googleapis/services/GoogleClientRequestInitializer;Ljava/lang/String;Z)V
    at com.google.api.services.youtube.YouTube.<init>(YouTube.java:135)
    at com.google.api.services.youtube.YouTube$Builder.build(YouTube.java:6446)
    at googleauthtest.Authentication.main(Authentication.java:54)
Java Result: 1
BUILD SUCCESSFUL (total time: 10 seconds)

JAR 依赖项 ::

请访问链接

Answer 1

NoSuchMethodError 表明您的 jar 版本不兼容。即

您有一个 jar 引用其他 jar 来调用 AbstractGoogleJsonClient 类的方法，其中 com.google.api.client.googleapis.services.json.AbstractGoogleJsonClient 类没有所需的方法！

解决方案是找到jar之间的依赖关系（版本依赖）并将jar更新到最新/对应的版本。

为什么不粘贴你的代码和jar版本？这样我们就可以查看使用的代码和罐子。