Spring 4.2.1 RestController tried to return template instead return JSON - spring

I tried to create a Spring Rest Controller, based on this example i create a controller like this.
DeveloperRestController.java
#RestController
public class DeveloperRestController {
#RequestMapping("/developer/list")
public Developer index() {
Developer developer = new Developer("Developername", "developer#yahoo.com");
return developer;
}
}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<filter>
<filter-name>sitemesh</filter-name>
<filter-class>org.sitemesh.config.ConfigurableSiteMeshFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>sitemesh</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener> <!--Here we specify about the DispatcherServlet class in the Web Deployment Descriptor-->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/dispatcher-servlet.xml</param-value>
</context-param>
</web-app>
dispatcher-servlet.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation=" http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.2.xsd">
<context:component-scan base-package="com.developerdata.controller" />
<context:annotation-config />
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>
But it shows 404 page not found, seems that spring tried to load a template...
Result:
Error 404 /WEB-INF/jsp/developer/list.jsp
what should i do?

Seems like you have a configuration issue. The sample you are basing yours on is spring boot based. So it handles the configuration for you. To get yours working you will need to add jackson to the classpath. If you are using maven then:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.6.2</version>
</dependency>
Then you need to alter your spring config to include:
<mvc:annotation-driven />
From the spring documentation:
The above registers a RequestMappingHandlerMapping, a
RequestMappingHandlerAdapter, and an ExceptionHandlerExceptionResolver
(among others) in support of processing requests with annotated
controller methods using annotations such as #RequestMapping,
#ExceptionHandler, and others.
This also then enables the MappingJackson2HttpMessageConverter if jackson 2 is in your classpath.
References:
http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/#mvc-config-enable
https://spring.io/guides/gs/rest-service/
http://www.mkyong.com/spring-mvc/spring-3-mvc-and-json-example/ (This one seems more appropriate for you to get started based on your problem)

With #ResponseBody, Spring will handle the JSON you need. Jackson
library is required too.
#RestController
public class DeveloperRestController {
#RequestMapping("/developer/list")
public #ResponseBody Developer index() {
Developer developer = new Developer("Developername", "developer#yahoo.com");
return developer;
}
}

Related

Spring MVC #GetMapping("") is executed three times in the first request

I've been working with Spring, I don't understand what the problem is. In the Test.class Spring MVC controller the code (the default controller, the first request will receive it) in the get request the code is executed three times this method includes 3 threads or 3 get requests.
Synchronized method and SingleThreadModel interface don't help, so I think the problem is with three requests?
If I execute the code in a different controller (not in the default fetch request) everything works good.
Test.class
#Controller
public class Test {
#GetMapping("")
public String hello(ModelMap model) {
System.out.println("method hello said 'yes'"); //runs twice
return "index";
}
}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="4.0" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd">
<display-name>Spring MVC</display-name>
<servlet>
<servlet-name>PredictWeather</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:servletsConfig.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>PredictWeather</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
servletsConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="servlets"/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
logs
Perhaps someone has come across, or knows how to solve the problem, thanks for any answer! I ask the question for the first time, perhaps it is poorly formulated

No mapping found for HTTP request with URI [/FitnessTracker/]

I am getting an warnning in springmvc
as No mapping found for HTTP request with URI [/FitnessTracker/] in DispatcherServlet with name 'fitTrackerServlet'
INFO: FrameworkServlet 'fitTrackerServlet': initialization completed in 2194 ms
Feb 26, 2017 9:43:08 AM org.springframework.web.servlet.DispatcherServlet noHandlerFound
WARNING: No mapping found for HTTP request with URI [/FitnessTracker/] in DispatcherServlet with name 'fitTrackerServlet'
When i press url http://localhost:8080/fitnessTracker/ I am getting 404 error.
Thanks
<?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_2_5.xsd" version="2.5">
<servlet>
<servlet-name>fitTrackerServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/config/servlet-config.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>fitTrackerServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
<display-name>Archetype Created Web Application</display-name>
</web-app>
and my servlet-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd">
<mvc:annotation-driven />
<context:component-scan base-package="com.pluralsight.controller"></context:component-scan>
<!--
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>
-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
p:prefix="/WEB-INF/jsp/" p:suffix=".jsp"/>
</beans>
and my controller
#Controller
public class HelloController {
#RequestMapping(value = "/greeting")
public String sayHello (Model model) {
System.out.println("Test");
model.addAttribute("greeting", "Hello WorldX");
return "hello";
}
}
Does your component-scan base-package match the package where your HelloController is in? If not, that is the problem.
<context:component-scan base-package="com.pluralsight.controller"></context:component-scan>
Configures component scanning directives for use with #Configuration
classes. Either basePackageClasses() or
basePackages() (or its alias value()) may be specified to define
specific packages to scan.
Spring does not find your HelloController and so doesn't map anything.
Otherwise you could also follow these steps.
I am wondering why you have you application configured with XML. With this tool you can start a maven project with a Spring boot application that will be, by default, already configured to build exactly what you want.
Then you only need a class with:
#RestController
#RequestMapping("/fitnessTracker")
public class HelloController {
#RequestMapping(value = "/greeting")
public String sayHello (Model model) {
System.out.println("Test");
model.addAttribute("greeting", "Hello WorldX");
return "hello";
}
}
And that's it, Spring will do the rest for you ;)
In my case the problem was that i was using this url-pattern
<url-pattern>/*</url-pattern>
instead of this
<url-pattern>/</url-pattern>
and also i had to add
#RequestMapping(value = "/fitnessTracker")
under the
#Controller
annotation.
I found the solution at : https://www.baeldung.com/spring-mvc-404-error for the pattern.

No mapping found for HTTP request with URI [/HelloWeb/WEB-INF/jsp/hello.jsp]

I tried to to load a simple example of spring mvc with a simple jsp but failed with the following error: No mapping found for HTTP request with URI [/HelloWeb/WEB-INF/jsp/hello.jsp]
I'm using Spring 3.2.2.
I really appreciate your help here.
I tried several thing but still it seems that I can not map my jsp page in the controller.
web.xml looks like that:
<web-app id="WebApp_ID" version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>Spring MVC Application</display-name>
<servlet>
<servlet-name>HelloWeb</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>HelloWeb</servlet-name>
<url-pattern>*.jsp</url-pattern>
</servlet-mapping>
</web-app>
HelloWeb-servlet.xml looks like that:
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation=" http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<context:component-scan base-package="com.tutorial.spring" />
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>
HelloControll.class looks like that:
package com.tutorial.spring;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
#Controller
#RequestMapping("/hello")
public class HelloController {
#RequestMapping(method= RequestMethod.GET)
public String printHello(ModelMap modelMap) {
modelMap.addAttribute("message", "Hello Spring MVC Framework!");
return "hello";
}
}
Correct URL to hit your printHello handler method is
/HelloWeb/hello.jsp
I figured it out. foolish mistake.
I named my jsp "Hello.jsp" with capital 'H' and returned in my controller 'hello' with lower case.
Just changed my jsp page to be "hello.jsp".
thanks for your help.
Modify web.xml like this
<servlet-mapping>
<servlet-name>HelloWeb</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
Try to access /YourAppName/hello. Then Spring-MVC will trigger the method printHello() . Then return the jsp view in /WEB-INF/jsp/.
The dispatcher servlet have to map the correct main route:
<servlet-mapping>
<servlet-name>HelloWeb</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
move jsp file to right place as defined in servlet
/WEB-INF/jsp/
The correct URL is http://localhost:8080/hello, without "/HelloWeb"

Sending HTML/JSON from REST Spring MVC Web app

I have developed a REST web application with Spring MVC and I can send JSON objects to a client.
I would like to construct a Javascript/AJAX client that connects to my web application but I don't know how to send the first HTML page (using JSP).
I understand I should serve JSP pages with some embedded AJAX. This AJAX will send requests to my web services.
Update:
The requirement I am not able to achieve is to write the default URI (http://localhost:8084) in browser and see the HTML page I have written in JSP page (home.jsp).
My approach is following:
I have a Controller that sends the root JSP page
#Controller
public class SessionController {
#RequestMapping(value="/", method=RequestMethod.GET)
public String homeScreen(){
return "home";
}
}
But when I run the server I receive this warning
WARNING: No mapping found for HTTP request with URI [/home] in DispatcherServlet with name 'dispatcher'
and nothing is loaded in browser.
Here is my application-context file:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd">
<context:component-scan base-package="com.powerelectronics.freesun.web" />
<mvc:annotation-driven />
</beans>
And web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/applicationContext.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>2</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
</web-app>
Is my approach correct? Am I wrong at any basic concept?
Can I modify something in my code to make it run?
I would like to see the first page loaded in browser and keep going in that direction.
Thanks in advance.
Try adding a #ResponseBody annotation on the method:
#Controller
public class SessionController {
#RequestMapping(value="/", method=RequestMethod.GET)
#ResponseBody
public String homeScreen(){
return "home";
}
}
This should output home on the page.
If you'd like to use View technologies, e.g. JSP, review the following chapter on the official Spring Framework documentation: http://static.springsource.org/spring/docs/3.1.x/spring-framework-reference/htmlsingle/spring-framework-reference.html#view
Update
"Just as with any other view technology you're integrating with Spring, for JSPs you'll need a view resolver that will resolve your views ". If you'd like to use JSP you should then add the following to your Web application context, then return the name of the file that shall be processed:
<!-- the ResourceBundleViewResolver -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.ResourceBundleViewResolver">
<property name="basename" value="views"/>
</bean>
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>
Is the above present in your Web application context? You can review the official documentation for further information: http://static.springsource.org/spring/docs/3.1.x/spring-framework-reference/htmlsingle/spring-framework-reference.html#view-jsp-resolver
Place a welcome file tag in web.xml file.
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
You must be having this index.jsp outside of WEB-INF. Put following code in it.
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
response.sendRedirect("home");
%>
</body>
</html>
When application is loaded, it will call index.jsp and jsp will redirect it to /home action.
Then your controller will get called.
#Controller
public class SessionController {
// see the request mapping value attribute here, it is /home
#RequestMapping(value="/home", method=RequestMethod.GET)
public String homeScreen(){
return "home";
}
}
This will call your home jsp.
If you want to to return JSON from your spring controller, then you need jackson mapper bean initialized in spring context xml file.
<beans:bean id="jacksonMessageChanger" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
<beans:property name="supportedMediaTypes" value="application/json" />
</beans:bean>
<beans:bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<beans:property name="messageConverters">
<util:list id="beanList">
<beans:ref bean="jacksonMessageChanger" />
</util:list>
</beans:property>
</beans:bean>
You need to add jar or maven dependency to use jackson mapper.
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.8.5</version>
</dependency>
And to return JSON from controller, method would be like this :
#RequestMapping(value="/getContacts", method=RequestMethod.GET)
public #ResponseBody List<Contacts> getContacts(){
List<Contacts> contactList = prepareContactList();
return contactList;
}
This way you will get List in the success function of ajax call in the form of object and by iterating it you can get the details.
Finally I solve this only with configuring the dispatcher in web.xml on a different way.
First I added the view resolver to the servlet configuration file as David Riccitelli suggested me:
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
p:prefix="/WEB-INF/jsp/" p:suffix=".jsp"/>
And then I configured the servlet mapping in web.xml:
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
That's what I was looking for, and no extra configuration is needed.
Doing this I call my root URL http://localhost:8084 and I can see the home screen I have coded in home.jsp.
Thanks for your support and suggestions.

Setting up Vaadin and Spring 3 - Autowiring fails (annotations)

I'm having some trouble using the #Autowire annotation of spring 3 in a vaadin application.
I have made a tiny test project with just a button which executes a method in an autowired service class.
I'm getting a NullPointerException when I click the button, because the service is never injected.
I have annotated the service with #Service("calculationService")
This is my application class:
package vaadinBaas;
// imports
public class MyVaadinApplication extends Application {
private Window window;
private CalculationService calculationService;
#Autowired
public void setCalculationService(CalculationService calculationService) {
this.calculationService = calculationService;
}
#Override
public void init() {
window = new Window("Show me the magic");
setMainWindow(window);
Button button = new Button("Click Me");
button.addListener(new Button.ClickListener() {
public void buttonClick(ClickEvent event) {
window.addComponent(new Label(String.valueOf(calculationService.multiply(10, 10))));
}
});
window.addComponent(button);
}
}
This is my spring application context:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:ct="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<ct:component-scan base-package="vaadinBaas" />
<ct:annotation-config />
<bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>
<bean class="org.springframework.context.annotation.CommonAnnotationBeanPostProcessor"/>
</beans>
And finally my web.xml:
<?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_2_5.xsd"
id="WebApp_ID" version="2.5">
<display-name>Vaadin Web Application</display-name>
<context-param>
<description>Vaadin production mode</description>
<param-name>productionMode</param-name>
<param-value>false</param-value>
</context-param>
<servlet>
<servlet-name>Vaadin Application Servlet</servlet-name>
<servlet-class>com.vaadin.terminal.gwt.server.ApplicationServlet</servlet-class>
<init-param>
<param-name>application</param-name>
<param-value>vaadinBaas.MyVaadinApplication</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>Vaadin Application Servlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:applicationContext.xml</param-value>
</context-param>
</web-app>
Am I missing something obvious here?
Try annotating MyVaadinApplication with Component annotation. Since MyVaadinApplication is not considered as spring managed class the Autowire didnt work for you. Also you need to load the bean definition xml using ClassPathXmlApplicationContext and try calling getBean(MyVaadinApplication.class) so that all the autowiring happens automatically

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