Develop Reference

Rest API java: java.lang.ClassNotFoundException: com.tutorialspoint.User

I'm quite new to Java and REST API and I have the following problem. I follow that link https://www.tutorialspoint.com/restful/restful_first_application.htm to learn how to build a REST API. I tried a few things, and I wanted to use my own package (com.ca) and updated my web.xml to the following:
<?xml version = "1.0" encoding = "UTF-8"?>
<web-app xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
xmlns = "http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
id = "WebApp_ID" version = "3.0">
<display-name>User Management</display-name>
<servlet>
<servlet-name>Jersey RESTful Application</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.ca</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>Jersey RESTful Application</servlet-name>
<url-pattern>/rest/*</url-pattern>
</servlet-mapping>
</web-app>
Nevertheless when I try to re-run the code on the server, and do a GET request I obtain the following:
java.lang.ClassNotFoundException: com.tutorialspoint.User
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1892)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1735)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:677)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1826)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1713)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2000)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1535)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:422)
at java.util.ArrayList.readObject(ArrayList.java:791)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1058)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2136)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2027)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1535)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:422)
at com.ca.UserDao.getAllUsers(UserDao.java:28)
at com.ca.UserService.getUsers(UserService.java:16)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory.lambda$static$0(ResourceMethodInvocationHandlerFactory.java:76)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:148)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:191)
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:243)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:103)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:493)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:415)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:104)
at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:277)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:272)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:268)
at org.glassfish.jersey.internal.Errors.process(Errors.java:316)
at org.glassfish.jersey.internal.Errors.process(Errors.java:298)
at org.glassfish.jersey.internal.Errors.process(Errors.java:268)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:289)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:256)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:703)
at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:416)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:370)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:389)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:342)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:229)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
It seems to still point on the previous package ( the one for the exercise), but I can't find why...Also if you have useful link about it ( how to setup the web.xml, every tag role,...) that would be helpful as well.
Thanks in advance.
UPDATE:
Here are the source files:
User.java:
package com.ca;
import java.io.Serializable;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
#XmlRootElement(name = "user")
public class User implements Serializable {
private static final long serialVersionUID = 1L;
private int id;
private String name;
private String profession;
public User(){}
public User(int id, String name, String profession){
this.id = id;
this.name = name;
this.profession = profession;
}
public int getId() {
return id;
}
#XmlElement
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
#XmlElement
public void setName(String name) {
this.name = name;
}
public String getProfession() {
return profession;
}
#XmlElement
public void setProfession(String profession) {
this.profession = profession;
}
}
UserDao.java:
package com.ca;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.List;
public class UserDao {
public List<User> getAllUsers(){
List<User> userList = null;
try {
File file = new File("Users.dat");
if (!file.exists()) {
User user = new User(1, "Mahesh", "Teacher");
userList = new ArrayList<User>();
userList.add(user);
saveUserList(userList);
}
else{
FileInputStream fis = new FileInputStream(file);
ObjectInputStream ois = new ObjectInputStream(fis);
userList = (List<User>) ois.readObject();
ois.close();
}
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return userList;
}
private void saveUserList(List<User> userList){
try {
File file = new File("Users.dat");
FileOutputStream fos;
fos = new FileOutputStream(file);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(userList);
oos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
UserService.java:
package com.ca;
import java.util.List;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
#Path("/UserService")
public class UserService {
UserDao userDao = new UserDao();
#GET
#Path("/users")
#Produces(MediaType.APPLICATION_XML)
public List<User> getUsers(){
return userDao.getAllUsers();
}
}
Update 2.0:
Screenshot of the project folder
Now I have the following:
<html>
<head>
<title>Apache Tomcat/7.0.81 - Error report</title>
<style>
<!--H1 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:22px;} H2 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:16px;} H3 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:14px;} BODY {font-family:Tahoma,Arial,sans-serif;color:black;background-color:white;} B {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;} P {font-family:Tahoma,Arial,sans-serif;background:white;color:black;font-size:12px;}A {color : black;}A.name {color : black;}HR {color : #525D76;}-->
</style>
</head>
<body>
<h1>HTTP Status 404 - /REST-Example/rest/UserService/users</h1>
<HR size="1" noshade="noshade">
<p>
<b>type</b> Status report
</p>
<p>
<b>message</b>
<u>/REST-Example/rest/UserService/users</u>
</p>
<p>
<b>description</b>
<u>The requested resource is not available.</u>
</p>
<HR size="1" noshade="noshade">
<h3>Apache Tomcat/7.0.81</h3>
</body>
</html>

Probably, you are missing some steps. I just followed the tutorial and everything works. The following is what I did:
Configure your system according to the instruction on tutorial site.
Create Eclipse Dynamic Web Project
Download Jersey 2.17 and expand it in a directory according to the instructions on the tutorial site.
Copy all of the JAR files except javax.servlet-api-3.0.1.jar into the WEB-INF/lib folder.
Create the classes User.java, UserDao.java, UserService.java and web.xml in the folders as shown on the screenshot.
Right click on the project (in my example: REST-Example) and select Export>WAR file to export the project to war file.
Copy the war file to the webapps folder of Tomcat and start it.
Start a browser of your choice and call http://localhost:8080/REST-Example/rest/UserService/users, where REST-Example is the name of the war file without the file extension.
If you're using Maven, it would even be simpler: you need to add one or two dependencies and Maven will take care of the rest.

NullPointerException in simple fileupload form using Spring MVC

I am trying to implement simple fileupload using Spring 4.2.3 and HTML form.
I have controller class which handles whole action, simple wrapper class for file, validator and simple view with form in HTML & Thymeleaf.
Almost everything is running fine, mapping works properly and view is appearing. But when I select file from disk and press upload button I have NullPointerException. Can anyone have a look and give some tips please? I have to mention that I am novice in Spring.
Controller:
#Controller
public class FileUploadController {
private static String UPLOAD_LOCATION = "C:/Temp/";
#Autowired
FileValidator fileValidator;
#InitBinder("file")
protected void initBinderFileBucket(WebDataBinder binder) {
binder.setValidator(fileValidator);
}
#RequestMapping(value = "/upload", method = RequestMethod.GET)
public String getSingleUploadPage(ModelMap model) {
FileBucket fileModel = new FileBucket();
model.addAttribute("fileBucket", fileModel);
return "views/fileUploader";
}
#RequestMapping(value = "/upload", method = RequestMethod.POST)
public String singleFileUpload(#Valid FileBucket file, BindingResult result, ModelMap model)
throws IOException {
if (result.hasErrors()) {
System.out.println("File Uploader validation error");
return "views/fileUploader";
} else {
System.out.println("Fetching file"); //prints out in console
MultipartFile multipartFile = file.getFile();
System.out.println(multipartFile.getName()); //NullPointer here
return "views/success";
}
}
}
File wrapper:
public class FileBucket {
private MultipartFile file;
//getters & setters + soon other stuff
}
Validator:
#Component
public class FileValidator implements Validator {
public boolean supports(Class<?> clazz) {
return FileBucket.class.isAssignableFrom(clazz);
}
public void validate(Object obj, Errors errors) {
FileBucket file = (FileBucket) obj;
if(file.getFile()!=null){
if (file.getFile().getSize() == 0) {
errors.rejectValue("file", "missingfile");
}
}
}
}
View:
<!DOCTYPE html>
<html xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout"
xmlns:th="http://www.thymeleaf.org"
layout:decorator="templates/baseTemplate">
<head>
<title>Upload Page</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<div layout:fragment="contentPanel" class="form-container">
<h1>Simple upload</h1>
<form method="POST" enctype="multipart/form-data" action="upload" >
<input type="file" name="file" /> <br />
<input type="submit" value="Upload" />
</form>
</div>
Demo
</body>
</html>
Stacktrace:
INFO: Starting ProtocolHandler ["http-bio-8080"]
Fetching file
kwi 23, 2016 12:39:36 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [spring] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at web.controllers.FileUploadController.singleFileUpload(FileUploadController.java:52)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
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.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1002)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

Okay I found out what's causing the problem.
After correcting name in #InitBinder to match argument in controller it was necessary to rename bean responsible for multipart resolving.
From:
#Bean public CommonsMultipartResolver commonsMultipartResolver() {
return new CommonsMultipartResolver();
}
To:
#Bean public CommonsMultipartResolver multipartResolver() {
return new CommonsMultipartResolver();
}
Otherwise it doesn't work.

How to return text_html type response in Jersey

I am developing a REST API using jersey jax-RS. This consumes data in JSON format and produces the output in html format.
When I set the MediaType for #Produces as TEXT_HTML and #Consumes as #APPLICATON_JSON and requested the 'GET' query on POSTMAN REST client, it gave me the following error:
org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [Jersey Web Application] in context with path [/try2] threw exception [org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyWriter not found for media type=text/html, type=class java.util.ArrayList, genericType=java.util.List<org.sc.try2.model.Event>.] with root cause
org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyWriter not found for media type=text/html, type=class java.util.ArrayList, genericType=java.util.List<org.sc.try2.model.Event>.
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.aroundWriteTo(WriterInterceptorExecutor.java:247)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.server.internal.JsonWithPaddingInterceptor.aroundWriteTo(JsonWithPaddingInterceptor.java:103)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.server.internal.MappableExceptionWrapperInterceptor.aroundWriteTo(MappableExceptionWrapperInterceptor.java:88)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.message.internal.MessageBodyFactory.writeTo(MessageBodyFactory.java:1154)
at org.glassfish.jersey.server.ServerRuntime$Responder.writeResponse(ServerRuntime.java:613)
at org.glassfish.jersey.server.ServerRuntime$Responder.processResponse(ServerRuntime.java:375)
at org.glassfish.jersey.server.ServerRuntime$Responder.process(ServerRuntime.java:365)
at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:272)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors$1.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:252)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1025)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:372)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:382)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:345)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:220)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
My codes :
StudentResource.java
package org.sc.try2.resources;
//import java.awt.Event;
import java.util.List;
import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
//import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import org.sc.try2.model.Student;
import org.sc.try2.service.StudentService;
#Path("/students")
#Consumes(MediaType.APPLICATION_JSON)
#Produces(MediaType.TEXT_HTML)
public class StudentResource {
StudentService studentService = new StudentService();
//EventService es = new EventService();
#GET
#Path("/{studentEmail}/viewAll")
public List<Student> getStudents(#PathParam("studentEmail") String emailID){
System.out.println("cmn in this method of StudentResource........ ");
return studentService.getAllStudents(emailID);
}
#GET
#Path("/{studentEmail}/viewMyProfile")
public Student getStudent(#PathParam("studentEmail") String emailID){
System.out.println("cmn in this method of StudentResource........ ");
return studentService.getStudent(emailID);
}
#Path("/{studentEmail}/events")
public AllEventsResource getEvents(){
System.out.println("cmn in this method of StudentResource ");
return new AllEventsResource();
}
#Path("/{studentEmail}/myevents")
public EventResource getStudentEvents(){
return new EventResource();
}
#PUT
#Path("/{studentEmail}/updateProfile")
public String updateStudent(#PathParam("studentEmail") String emailID,Student student){
//student.setEmailID(emailID);
return studentService.updateStudent(emailID,student);
}
#DELETE
#Path("/{studentEmail}/deleteStudent/{delEmail}")
public String deleteStudent(#PathParam("studentEmail") String emailID,#PathParam("delEmail") String delEmail){
return studentService.removeStudent(emailID,delEmail);
}
}
EventsResource.java
package org.sc.try2.resources;
import java.util.List;
import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import org.sc.try2.model.Event;
import org.sc.try2.service.EventService;
#Path("/")
#Consumes(MediaType.APPLICATION_JSON)
#Produces(MediaType.TEXT_HTML)
public class EventResource {
EventService es = new EventService();
#GET
public List<Event> getMyEvents(#PathParam("studentEmail") String emailID){
System.out.println("cmn in this method of EventsResource ");
return es.getAllEventsForStudent(emailID);
}
#POST
public String addEvent(#PathParam("studentEmail") String email,Event event){
System.out.println("here in res add evnt..");
return es.addEvent(email,event);
}
#PUT
#Path("/{eventId}")
public String updateEvent(#PathParam("studentEmail") String email,#PathParam("eventId") long id,Event event){
event.seteID(id);
return es.updateEvent(email,id,event);
}
#DELETE
#Path("/{eventId}")
public String deleteEvent(#PathParam("studentEmail") String email,#PathParam("eventId") long id){
return es.removeEvent(email,id);
}
}
On searching about this on the internet, I did not come across any useful solution except it was mentioned to download the genson jar and add it. After adding it as external jar in Eclipse (Java EE) MAVEN Project, it still gave the same exception which I guess is due to the fact that this jar is for json MediaType and is not used in the context of html content type.
Basically, I want to produce the content as HTML. How can I do it? I am entirely new to Jersey and the concept of REST API.

File upload in Spring MVC gives NullPointerException

I have a simple JSP form as follows:
<p>Please select a file and <i>click</i> <i>Upload file</i> to upload the file to the server:</p>
<c:url value="/upload/display" var="displayUploadedFileURL" />
<form:form action="${displayUploadedFileURL}" method="post" modelAttribute="upload" enctype="multipart/form-data">
<input type="file" name="file" />
<input type="submit" value="Upload file" /> <form:errors path="file" />
<input type="Reset" value="Reset">
</form:form>
Which is for a user to upload a file to the server. The controller's method is as follows:
#Controller
#RequestMapping("/upload")
public class UploadController {
#Autowired
private UploadValidator uploadValidator;
#RequestMapping(value="/display", method=RequestMethod.POST)
public String displayUploadedFile(#ModelAttribute("upload") Upload upload,
BindingResult bindingResult,
Model model) {
// Validate Upload.
uploadValidator.validate(upload, bindingResult);
if (bindingResult.hasErrors()) {
return ("view/upload/select");
}
else {
String fileName = upload.getFile().getOriginalFilename();
System.out.println("Here: " + upload.getFile().getOriginalFilename());
model.addAttribute("fileName", fileName);
return ("view/upload/display");
}
}
...
But when I select a file and use the Upload file button I get the following:
Your page request has caused a NullPointerException: error:
library.validator.UploadValidator.validate(UploadValidator.java:29)
library.controller.upload.UploadController.displayUploadedFile(UploadController.java:45)
The validator concerned is very simple:
package library.validator;
import library.model.Upload;
import org.apache.log4j.Logger;
import org.springframework.stereotype.Component;
import org.springframework.validation.Errors;
import org.springframework.validation.Validator;
#Component
public class UploadValidator implements Validator {
private static final Logger logger = Logger.getLogger(UploadValidator.class);
public UploadValidator() {
}
#Override
public boolean supports(Class cls) {
return Upload.class.isAssignableFrom(cls);
}
#Override
public void validate(Object target, Errors errors) {
logger.info(UploadValidator.class.getName() + ".validate() method called.");
Upload upload = (Upload) target;
if (upload.getFile().getSize() == 0) {
errors.rejectValue("file", "file.required");
}
}
}
I have all the relevant .jar files in the application's .lib folder, and I'mincluding the following:
<bean id="uploadValidator" class="library.validator.UploadValidator" />
<!-- Spring multipartResolver. -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver" />
In the DispatcherServlet.
The Upload object type is as follows:
import org.springframework.web.multipart.MultipartFile;
public class Upload {
private MultipartFile file;
And appropriate getter and setter.
So why is my code not working?
Stacktrace for current problem, i.e. allowing for changes to controller method in answer below, is:
org.springframework.util.Assert.notNull(Assert.java:112)
org.springframework.web.method.annotation.RequestParamMethodArgumentResolver.resolveName(RequestParamMethodArgumentResolver.java:171)
org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:89)
org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:79)
org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:157)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:124)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:690)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
java.lang.Thread.run(Thread.java:744)

Configuring the multipartResolver bean is important thing, but also you should check that your .xml config file with this bean is imported in your general applicationContext.xml, if you have some. I had same problem and this did the thing.

This has now been solved. The problem was that the following was incorrectly defined in the DispatcherServlet:
<!-- Spring multipartResolver. -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver" />

Error while calling a method which passes request and response For storing a file to MYSQL databases

i am developing a project KNOWLEDGE based community sharing system.
in which users can login and share their resources to other Users....
I'm getting a problem in uploading a file to mysql database....
PS..my Instructor strictly Says to use MVC architecture So, i have to use the same..
So i have created only one Servlet named Controller.java.
here i will redirect to other java programs for calculations...
Here is the code for Controller.java
package com.kbcss.controller;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.kbcss.command.LoginCommand;
import com.kbcss.command.Commands;
import com.kbcss.command.ResourceCommand;
import com.kbcss.command.UserCommand;
public class Controller extends HttpServlet {
private static final long serialVersionUID = 1L;
public Controller() {super();}
#SuppressWarnings("rawtypes")
private Map commands = new HashMap();
#SuppressWarnings("unchecked")
public void init(ServletConfig config) throws ServletException{
super.init();
System.out.println("i am in init");
this.commands.put("login", new LoginCommand());
this.commands.put("user", new UserCommand());
this.commands.put("resource", new ResourceCommand());
System.out.println("i am about to exit init");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("i am in doget");
processCommand(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("i am in dopost");
processCommand(request, response);
}
private void processCommand(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("i am in processCommand");
String formAction = request.getParameter("form_action");
System.out.println("i am in processCommand state 2");
Commands command = (Commands) commands.get(formAction);
command.execute(request, response);
System.out.println("i am about to exit processCommand");
}
}
and here is the code for saving the resources to MY database table.... Named ResourceCommand .java
package com.kbcss.command;
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.PreparedStatement;
import javax.naming.InitialContext;
import javax.naming.Context;
import javax.sql.DataSource;
import com.oreilly.servlet.MultipartRequest;
public class ResourceCommand extends HttpServlet implements Commands{
private static final long serialVersionUID = 1L;
public void execute(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
//
// JNDI to connect to database
//
Connection conn = null;
Context initContext = new InitialContext();
Context envContext = (Context)initContext.lookup("java:/comp/env");
DataSource ds = (DataSource)envContext.lookup("jdbc/tia");
conn = ds.getConnection();
//
// Save file(s) temporarily to filesystem
//
MultipartRequest multi = new MultipartRequest(request, "F:", 10*1024*1024);
Enumeration files = multi.getFileNames();
String filename = "";
File f = null;
while(files.hasMoreElements()) {
String name = (String)files.nextElement();
filename = multi.getFilesystemName(name);
String type = multi.getContentType(name);
f = multi.getFile(name);
}
//
// Insert file into database
//
InputStream is = new FileInputStream(f);
String sql = "INSERT INTO resource (`title`, `cat`, `user`, `filename`, `file`, `like`) VALUES (?, ?, ?, ?, ?, ?)"
;
PreparedStatement stmt = conn.prepareStatement(sql);
// Set some Title
stmt.setString(1, "some thing");
// Set some category
stmt.setString(2, ".net");
// Set some user
stmt.setString(3, "sri");
// Set Filename
stmt.setString(4, f.getName());
// Set the data
stmt.setBinaryStream(5, is, (int) f.length());
// Set Likes
stmt.setInt(6, 2);
stmt.executeUpdate();
is.close();
//
// Release connection
//
if (stmt != null) {
try { stmt.close(); } catch (SQLException e) { ; }
stmt = null;
}
if (conn != null) {
try { conn.close(); } catch (SQLException e) { ; }
conn = null;
}
} catch(Exception e) {
System.out.println(e);
}
}
}
And here is the jSP file where i will upload from....
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>UPLOAD FILE page</title></head>
<body>
<form method="post" action="Controller" enctype="multipart/form-data">
<input type="hidden" name="form_action" value="resource" />
<b>File to upload to database:</b>
<input type="file" name="attachment" size="36">
<input type="submit" value="Upload">
</form>
</body></html>
And this is the error i'm getting :(
INFO: Reloading Context with name [/KBCSS] is completed
i am in init
i am about to exit init
i am in dopost
i am in processCommand
i am in processCommand state 2
Oct 10, 2013 11:29:59 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [Controller] in context with path [/KBCSS] threw exception
java.lang.NullPointerException
at com.kbcss.controller.Controller.processCommand(Controller.java:69)
at com.kbcss.controller.Controller.doPost(Controller.java:53)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
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:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
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:1023)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
and by the way..i have created a Command.java interface here it is.
package com.kbcss.command;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.*;
public interface Commands {
public void execute(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException;
}
Can any one guide me PLZZZZZZZZZZZZZZZZZZZZ
i'm stuck for a day and Half and have no clue what i'm doing...
This is what happens if u ask an electrical engineering student to do a Java Project !!!!
GREAT GREAT thanks from My side.....

Chances are that commands.get(formAction); is returning null, so command is also null. When you call command.execute(request, response);, you're trying to access something within a null object. That's going to get you a NullPointerException.
Use your print statements to determine what the exact value of formAction is when you get the exception. Then verify that you're putting a key for that string into commands (if it isn't "login", "user", or "resource", since you're already entering those).
One other thing that may be causing the problem is that you need to add class-types to your Map. Change it to:
private Map<String,Command> commands = new HashMap<String,Command>();
After you do that, you shouldn't have to suppress the warning on the Map.