使用Google App Engine for Java的ClassNotFoundException

Question

我和朋友正在使用Java SDK在App Engine中進行遊戲。我們有 彙總了一個「你好，世界」的例子，沒有問題;然而，當我們 嘗試添加代碼com.google.api.client.http使用 類，可以到WebService一個簡單的通話，我們的代碼編譯罰款，但 導致運行時錯誤：

HTTP ERROR 500 

Problem accessing /surreality. Reason: 

    com/google/api/client/http/HttpTransport 

Caused by: 

HTTP ERROR 500 

Problem accessing /surreality. Reason: 

    com/google/api/client/http/javanet/NetHttpTransport 

Caused by: 

java.lang.NoClassDefFoundError: com/google/api/client/http/javanet/ 
NetHttpTransport 
     at 
com.surreality.scratch.SurrealityServlet.performSearch(SurrealityServlet.java: 
31) 
     at 
com.surreality.scratch.SurrealityServlet.doGet(SurrealityServlet.java: 
18) 
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:617) 
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
     at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java: 
511) 

（...切）

有問題的代碼是：

package com.surreality.scratch; 

import java.io.IOException; 
import javax.servlet.http.*; 
import java.util.List; 
import com.google.api.client.googleapis.*; 
import com.google.api.client.http.*; 
import com.google.api.client.http.javanet.*; 
import com.google.api.client.util.Key; 

@SuppressWarnings("serial") 
public class SurrealityServlet extends HttpServlet { 

     public void doGet(HttpServletRequest req, HttpServletResponse resp) 
         throws IOException { 
       resp.setContentType("text/plain"); 
       try { 
         this.performSearch(resp); 
         resp.getWriter().println("Here..."); 
       } catch (Exception e) { 
         resp.getWriter().println("Onoes!"); 
       } 
     } 

     public void performSearch(HttpServletResponse resp) throws Exception 
{ 

       try { 
         resp.getWriter().println("Perform Search ...."); 
         resp.getWriter().println("-------------------"); 

         HttpTransport transport = new NetHttpTransport(); // This line 
causes our servlet to implode on every request 
       } catch (Exception e) { 
         resp.getWriter().println("failed"); 
         throw e; 
       } 
     } 
} 

我們最好的猜測是構建類路徑和 運行時類路徑，但我們的運行時類路徑之間的差異似乎是確定的。該 HttpTransport類是在谷歌的API客戶端-1.4.1-beta.jar 庫，而這包含在命令行Eclipse是產生 運行項目：

/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/ 
java -Ddatastore.default_high_rep_job_policy_unapplied_job_pct=50 - 
Xmx512m -javaagent:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/agent/appengine-agent.jar - 
XstartOnFirstThread -Xbootclasspath/p:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/override/appengine-dev-jdk-overrides.jar - 
Dfile.encoding=MacRoman -classpath /Users/Arkaaito/Documents/AppEngine/ 
scratch/surreality/war/WEB-INF/classes:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/shared/appengine-local-runtime- 
shared.jar:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/shared/el-api.jar:/Applications/eclipse/ 
plugins/com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/shared/jsp/repackaged-appengine- 
ant-1.7.1.jar:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/shared/jsp/repackaged-appengine-ant- 
launcher-1.7.1.jar:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/shared/jsp/repackaged-appengine- 
jasper-6.0.29.jar:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/shared/jsp/repackaged-appengine-jasper- 
el-6.0.29.jar:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/shared/jsp/repackaged-appengine-tomcat- 
juli-6.0.29.jar:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/shared/jsp-api.jar:/Applications/eclipse/ 
plugins/com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/shared/servlet-api.jar:/Applications/ 
eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/appengine-api-1.0-sdk-1.5.3.jar:/ 
Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/appengine-api-labs-1.5.3.jar:/ 
Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/appengine-jsr107cache-1.5.3.jar:/ 
Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/jsr107cache-1.1.jar:/Applications/ 
eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/orm/datanucleus- 
appengine-1.0.9.final.jar:/Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/orm/datanucleus-core-1.1.5.jar:/ 
Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/orm/datanucleus-jpa-1.1.5.jar:/ 
Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/orm/geronimo-jpa_3.0_spec-1.1.1.jar:/ 
Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/orm/geronimo-jta_1.1_spec-1.1.1.jar:/ 
Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/user/orm/jdo2-api-2.3-eb.jar:/ 
Applications/eclipse/plugins/ 
com.google.appengine.eclipse.sdkbundle_1.5.3.r37v201108301710/ 
appengine-java-sdk-1.5.3/lib/appengine-tools-api.jar:/Users/Arkaaito/ 
Documents/AppEngine/scratch/surreality/war/WEB-INF/lib/google-api-java- 
client-1.4.1-beta/dependencies/httpclient-4.0.3.jar:/Users/Arkaaito/ 
Documents/AppEngine/scratch/surreality/war/WEB-INF/lib/google-api-java- 
client-1.4.1-beta/dependencies/httpcore-4.0.1.jar:/Users/Arkaaito/ 
Documents/AppEngine/scratch/surreality/war/WEB-INF/lib/google-api-java- 
client-1.4.1-beta/google-api-client-1.4.1-beta.jar:/Users/Arkaaito/ 
Documents/AppEngine/scratch/surreality/war/WEB-INF/lib/google-api-java- 
client-1.4.1-beta/google-api-client-googleapis-1.4.1-beta.jar:/Users/ 
Arkaaito/Documents/AppEngine/scratch/surreality/war/WEB-INF/lib/google- 
api-java-client-1.4.1-beta/google-api-client-extensions-1.4.1- 
beta.jar:/Users/Arkaaito/Documents/AppEngine/scratch/surreality/war/ 
WEB-INF/lib/google-api-java-client-1.4.1-beta/google-api-client- 
googleapis-extensions-1.4.1-beta.jar:/Users/Arkaaito/Documents/ 
AppEngine/scratch/surreality/war/WEB-INF/lib/geronimo- 
jpa_3.0_spec-1.1.1.jar:/Users/Arkaaito/Documents/AppEngine/scratch/ 
surreality/war/WEB-INF/lib/geronimo-jta_1.1_spec-1.1.1.jar 
com.google.appengine.tools.development.DevAppServerMain --port=3333/
Users/Arkaaito/Documents/AppEngine/scratch/surreality/war 

有沒有人遇到這個問題之前還是沒有人有我們應該做的調試 建議？我確定這很簡單，可能是一個配置問題，但作爲新手，我們不知道除了classpath之外還需要看什麼。

Answer 1

在您WEB-INF/lib目錄，你有一些子目錄google-api-java-client-1.4.1-beta和google-api-java-client-1.4.1-beta/dependencies用罐子那些子目錄中，應該是內WEB-INF/lib

Answer 2

您是否在WEB-INF/lib中有all of the dependencies？