servlet [Jersey REST Service] 的 Servlet.service() java.lang.NullPointerException
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Servlet.service() for servlet [Jersey REST Service] java.lang.NullPointerException
提问by blitzen12
can anyone help me work around with this one. This is my first time to create restful api.
谁能帮我解决这个问题。这是我第一次创建restful api。
web.xml
网页.xml
<display-name>1FxAll</display-name>
<servlet>
<servlet-name>Jersey REST Service</servlet-name>
<servlet-class>
org.glassfish.jersey.servlet.ServletContainer
</servlet-class>
<init-param>
<param-name>jersey.config.server.provider.packages</param-name>
<param-value>com.sample.blitz</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Jersey REST Service</servlet-name>
<url-pattern>/api/*</url-pattern>
</servlet-mapping>
UserController.java
用户控制器.java
package com.sample.blitz;
@Path("/user")
public class UserController{
@GET
@Produces(MediaType.TEXT_PLAIN)
public String test(){
return "user";
}
}
full stacktrace error.
完整的堆栈跟踪错误。
SEVERE: Servlet.service() for servlet [Jersey REST Service] in context with path [/1FxAll] threw exception [java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at com.sample.blitz.UserController.test(UserController.java:28)
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:606)
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory.invoke(ResourceMethodInvocationHandlerFactory.java:81)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.run(AbstractJavaResourceMethodDispatcher.java:151)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:171)
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:195)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:104)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:384)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:342)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:101)
at org.glassfish.jersey.server.ServerRuntime.run(ServerRuntime.java:271)
at org.glassfish.jersey.internal.Errors.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:297)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:254)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1030)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:373)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:381)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:344)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:221)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
it keep saying that the error is at UserController line 28 but when I check there is no line 28.
它一直说错误在 UserController 第 28 行，但是当我检查时没有第 28 行。
I am using Tomcat 7.0. I also tried to switch to glassfish but I got the same error.
我正在使用 Tomcat 7.0。我也尝试切换到 glassfish，但我遇到了同样的错误。
Thanks..
谢谢..
回答by blitzen12
I'll just post my answer here.
我只会在这里发布我的答案。
I'm not sure what's relevant with glassfish 4.0and 4.1but after I change glassfish version from 4.0to 4.1and remove jersey file from lib folder it seems working but in tomcat I still got NullPointerException. This will only work on glassfish 4.1.
我不知道什么是与相关的glassfish 4.0和4.1，但之后我改变从GlassFish的版本4.0，以4.1和删除文件的球衣从lib文件夹似乎工作，但在Tomcat中我仍然有NullPointerException异常。这仅适用于glassfish 4.1.
回答by Naveenkumar
You have add the following dependency for the RESTFull
您已经为 RESTFull 添加了以下依赖项
<dependency>
<groupId>org.glassfish.jersey.ext</groupId>
<artifactId>jersey-spring3</artifactId>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.ext</groupId>
<artifactId>jersey-bean-validation</artifactId>
</dependency>
回答by OO7
Remove /from @Path("/user")& make it as @Path("user"). Bcoz, u have already given path like /api/*in the <url-pattern>I think there is double occurrences of /
删除/从@Path("/user")＆使它作为@Path("user")。Bcoz，你已经给出了路径/api/*，<url-pattern>我认为有两次出现/
Change your UserControllerClass as
将您的UserController班级更改为
package com.sample.blitz;
@Path("user")
public class UserController{
@GET
@Produces(MediaType.TEXT_PLAIN)
public String test(){
return "user";
}
}
回答by Noli
When you create object of the service instantiate it with new key word.
当您创建服务的对象时，用新的关键字实例化它。
Xservice x = new Xservice();
