你好，我用的Eclipse，我測試Google官方的代碼，但是報錯,你能告訴我答案嘛？
Exception in thread "main" java.lang.NullPointerException: No API environment is registered for this thread.
at com.google.appengine.api.datastore.DatastoreApiHelper.getCurrentAppId(DatastoreApiHelper.java:62)
at com.google.appengine.api.datastore.KeyTranslator.convertToPb(KeyTranslator.java:55)
at com.google.appengine.api.datastore.EntityTranslator.convertToPb(EntityTranslator.java:33)
at com.google.appengine.api.datastore.DatastoreServiceImpl$2.run(DatastoreServiceImpl.java:165)
at com.google.appengine.api.datastore.TransactionRunner.runInTransaction(TransactionRunner.java:29)
at com.google.appengine.api.datastore.DatastoreServiceImpl.put(DatastoreServiceImpl.java:157)
at com.google.appengine.api.datastore.DatastoreServiceImpl.put(DatastoreServiceImpl.java:137)
at com.google.appengine.api.datastore.DatastoreServiceImpl.put(DatastoreServiceImpl.java:129)
at org.datanucleus.store.appengine.RuntimeExceptionWrappingDatastoreService.put(RuntimeExceptionWrappingDatastoreService.java:92)
at org.datanucleus.store.appengine.DatastorePersistenceHandler.put(DatastorePersistenceHandler.java:108)
at org.datanucleus.store.appengine.DatastorePersistenceHandler.put(DatastorePersistenceHandler.java:94)
at org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject(DatastorePersistenceHandler.java:195)
at org.datanucleus.state.JDOStateManagerImpl.internalMakePersistent(JDOStateManagerImpl.java:3067)
at org.datanucleus.state.JDOStateManagerImpl.makePersistent(JDOStateManagerImpl.java:3043)
at org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1258)
at org.datanucleus.ObjectManagerImpl.persistObject(ObjectManagerImpl.java:1135)
at org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent(JDOPersistenceManager.java:668)
at org.datanucleus.jdo.JDOPersistenceManager.makePersistent(JDOPersistenceManager.java:693)
at com.china.bill.dao.EmployeeDao.main(EmployeeDao.java:25)
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@bill
我用的不是 Ecplise ，您可以改用Netbeans  回復  更多評論
  

測試的時候不要狂刷哦，刷爆了我可不負責任，呵呵   回復  更多評論
  

@左洸

我可不可以寫個main函數測試？我上面的代碼就是在main函數里進行持久化的。？？  回復  更多評論
  

我用的netBeans報錯：
java.lang.NullPointerException
com.google.appengine.api.users.UserServiceImpl.getCurrentUser(UserServiceImpl.java:79)
guestbook.GuestbookServlet.doGet(GuestbookServlet.java:61)
javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
但是我上傳到Google app engine 上后是正常的，請問這是為什么呢？
另一段錯誤：
type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /guestbook.jsp at line 23

20:
21: <%
22: UserService userService = UserServiceFactory.getUserService();
23: User user = userService.getCurrentUser();
24: if (user != null) {
25: %>
26: <p>Hello, <%= user.getNickname() %>! (You can


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause

java.lang.NullPointerException
com.google.appengine.api.users.UserServiceImpl.getCurrentUser(UserServiceImpl.java:79)
org.apache.jsp.guestbook_jsp._jspService(guestbook_jsp.java:74)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)  回復  更多評論