저는 GAE 및 클라우드 엔드 포인트에서 막 시작했습니다. 샘플 영속 클래스를 만들었고 이클립스에서 google 메뉴를 사용하여 enpoint 클래스를 생성했습니다. 이제는 curl
을 사용하는 방법에 대한 자습서를 따랐으며 좋은 json
문자열을 얻었고 분명히 모든 값을 nullpointerexception
을 던지는 목록으로 만들려고 할 때 놀랍게도 URL 문자열에 ID를 제공하면 마술처럼 작동합니다. 지금 내 관심은이 오류 오류를 제기 listContinent
메소드를 호출한다기본 키로 검색하는 대신 목록을 가져 오려고 할 때 Google 애플리케이션 엔진 nullpointerexception
curl http://localhost:8888/_ah/api/app/v1/continent
를 만드는 것입니다 즉 listContinent
및 getContinent
이 두 가지 방법입니다.
이 하나가 바로 작동 getContinent
메소드를 호출한다
curl http://localhost:8888/_ah/api/app/v1/continent/1
올바른 Id
가 예상대로 작동하는 URL을 통해 전달 될 때.
이 내 엔드 포인트 클래스 -
@Api(name = "app")
public class ContinentEndpoint {
@SuppressWarnings({ "cast", "unchecked" })
public List<Continent> listContinent() {
PersistenceManager mgr = getPersistenceManager();
List<Continent> result = new ArrayList<Continent>();
try {
Query query = mgr.newQuery(Continent.class);
for (Object obj : (List<Object>) query.execute()) {
result.add(((Continent) obj));
}
} finally {
mgr.close();
}
return result;
}
public Continent getContinent(@Named("id") Long id) {
PersistenceManager mgr = getPersistenceManager();
Continent continent = null;
try {
continent = mgr.getObjectById(Continent.class, id);
} finally {
mgr.close();
}
return continent;
}
private static PersistenceManager getPersistenceManager() {
return PMF.get().getPersistenceManager();
}
}
이 내 영속 클래스입니다 - 이것은 내가 디버깅을했고, 내가 발견
Nov 12, 2012 3:07:10 PM com.google.apphosting.utils.jetty.JettyLogger info
INFO: Logging to JettyLogger(null) via com.google.apphosting.utils.jetty.JettyLogger
Nov 12, 2012 3:07:10 PM com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
INFO: Successfully processed /home/soham/Workspace/cloudcv/war/WEB-INF/appengine-web.xml
Nov 12, 2012 3:07:10 PM com.google.apphosting.utils.config.AbstractConfigXmlReader readConfigXml
INFO: Successfully processed /home/soham/Workspace/cloudcv/war/WEB-INF/web.xml
Nov 12, 2012 8:37:11 PM com.google.appengine.tools.development.DevAppServerImpl start
INFO: The server is running at http://localhost:8888/
Nov 12, 2012 8:37:11 PM com.google.appengine.tools.development.DevAppServerImpl start
INFO: The admin console is running at http://localhost:8888/_ah/admin
Nov 12, 2012 8:37:53 PM com.google.api.server.spi.SystemService invokeServiceMethod
SEVERE: null
java.lang.NullPointerException
at com.google.appengine.datanucleus.query.QueryEntityPKFetchFieldManager.fetchLongField(QueryEntityPKFetchFieldManager.java:74)
at org.datanucleus.identity.IdentityUtils.getApplicationIdentityForResultSetRow(IdentityUtils.java:101)
at com.google.appengine.datanucleus.EntityUtils.entityToPojo(EntityUtils.java:1009)
at com.google.appengine.datanucleus.query.DatastoreQuery$2.apply(DatastoreQuery.java:228)
at com.google.appengine.datanucleus.query.DatastoreQuery$2.apply(DatastoreQuery.java:225)
at com.google.appengine.datanucleus.query.LazyResult.resolveNext(LazyResult.java:96)
at com.google.appengine.datanucleus.query.LazyResult$LazyAbstractListIterator.computeNext(LazyResult.java:229)
at com.google.appengine.datanucleus.query.AbstractIterator.tryToComputeNext(AbstractIterator.java:131)
at com.google.appengine.datanucleus.query.AbstractIterator.hasNext(AbstractIterator.java:126)
at com.google.appengine.datanucleus.query.LazyResult$AbstractListIterator.hasNext(LazyResult.java:183)
at com.cloudcv.ContinentEndpoint.listContinent(ContinentEndpoint.java:23)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:115)
at com.google.api.server.spi.SystemService.invokeServiceMethod(SystemService.java:254)
at com.google.api.server.spi.SystemServiceServlet.execute(SystemServiceServlet.java:135)
at com.google.api.server.spi.SystemServiceServlet.doPost(SystemServiceServlet.java:106)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:123)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:61)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:94)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:383)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
내 스택 트레이스가
@PersistenceCapable(identityType = IdentityType.APPLICATION)
@Version(strategy = VersionStrategy.VERSION_NUMBER)
public class Continent {
public long getContinentId() {
return continentId;
}
public void setContinentId(long continentId) {
this.continentId = continentId;
}
public String getContinentName() {
return continentName;
}
public void setContinentName(String continentName) {
this.continentName = continentName;
}
public Date getCreatedOn() {
return createdOn;
}
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private long continentId;
private String continentName;
private Date createdOn = new Date();
}
입니다 Query query = mgr.newQuery(Continent.class);
의 검색어는 아무 것도 반환하지 않으며 루프는 for each
입니다. ArrayList
을 채우지 않습니다.
코드를 표시하면 사람들이 귀하를 도울 수있게됩니다. – Amber
@Amber 그냥했습니다. –
메소드 listContinent를 단위 테스트 했습니까? 제대로 작동 했습니까? –