Pradyut Bhattacharya Pradyut Bhattacharya - 19 days ago 9
Java Question

Jersey not able to map json request to class

I m able to run Jersey with Json output and able to get "GET" requests with JSon mapping without any problems.

I was also having some JSON methods which were "POST" methods and they are mapping to Java classes like in this method -

@POST
@Consumes({MediaType.APPLICATION_JSON})
@Produces({MediaType.TEXT_PLAIN})
@Path("/post")
public String postPerson(Person pers)


For your reference I m following the guide here or here

On giving a valid post request on these, they all started to throw the below error -

My maven dependencies, pom.xml is file at the end of the question -

exception

javax.servlet.ServletException: java.lang.NullPointerException
org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:489)
org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:427)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:388)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:341)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:228)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)

root cause

java.lang.NullPointerException
newa.PersonResource.postPerson(PersonResource.java:31)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory$1.invoke(ResourceMethodInvocationHandlerFactory.java:81)
org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:144)
org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:161)
org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:205)
org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:99)
org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:389)
org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:347)
org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:102)
org.glassfish.jersey.server.ServerRuntime$2.run(ServerRuntime.java:326)
org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
org.glassfish.jersey.internal.Errors.process(Errors.java:315)
org.glassfish.jersey.internal.Errors.process(Errors.java:297)
org.glassfish.jersey.internal.Errors.process(Errors.java:267)
org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317)
org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:305)
org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1154)
org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:473)
org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:427)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:388)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:341)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:228)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)


The Person class -

@JsonInclude(Include.NON_EMPTY)
public class Person {
private String firstName;
private String lastName;
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getLastName() {
return lastName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
}


The data I m sending using postman(Chrome extension) is in like -

screenshot

My pom.xml file -

<dependencies>


<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>



<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-servlet</artifactId>
<version>2.24</version>
</dependency>

<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-json-jackson</artifactId>
<version>2.24</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-json-processing</artifactId>
<version>2.24</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-multipart</artifactId>
<version>2.24</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-sse</artifactId>
<version>2.24</version>
</dependency>

<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-core</artifactId>
<version>1.8</version>
<type>jar</type>
</dependency>
</dependencies>

Answer

From the looks of the postman screenshot, it looks like you are sending over form-data, when you are actually wanting json (unless this is a new way you can input post data into POSTMAN. I just tried and could only input form-data this way).

Go to postman, click on the body tab, click the raw radio button, then choose application/json from the dropdown menu on the right. From there, input your body as json, which would look something like:

{"firstName": "Bill", "lastName": "Loney"}