HandlerMapping is an Interface to be implemented by objects that define a mapping between requests and handler objects. By default DispatcherServlet uses BeanNameUrlHandlerMapping and DefaultAnnotationHandlerMapping. In Spring MVC we majorly use the below handler mappings
- BeanNameUrlHandlerMapping
- ControllerClassNameHandlerMapping
- SimpleUrlHandlerMapping
Let’s take BeanNameUrlHandlerMapping in this article. Here we will be mapping each request to a Bean directly like below
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
<bean name="/helloWorld.htm"
class="com.javainterviewpoint.HelloWorldController" />
<bean name="/hello*.htm"
class="com.javainterviewpoint.HelloWorldController" />
Here we can see we have mentioned the Spring container to use BeanNameUrlHandlerMapping and we have mapped each possible request to a controller.
Folder Structure :
- Create a Dynamic Web Project “SpringMVCHandlerMappingTutorial” and create a package for our src files “com.javainterviewpoint“
- Place the Spring 3 jar files under WEB-INF/Lib
commons-logging-1.1.1.jar
log4j-1.2.16.jar
slf4j-api-1.7.5.jar
slf4j-log4j12-1.7.5.jar
spring-aspects-3.2.4.RELEASE.jar
spring-beans-3.2.4.RELEASE.jar
spring-context-3.2.4.RELEASE.jar
spring-core-3.2.4.RELEASE.jar
spring-expression-3.2.4.RELEASE.jar
spring-web-3.2.4.RELEASE.jar
spring-webmvc-3.2.4.RELEASE.jar - Create the Java classes HelloWorldController.java and WelcomeController.java under com.javainterviewpoint folder.
- Place the SpringConfig-servlet.xml and web.xml under the WEB-INF directory
- View files helloWorld.jsp and welcome.jsp are put under the sub directory under WEB-INF/Jsp
HelloWorldController.java
Our HelloWorldController class extends AbstractController class and overrides “handleRequestInternal()” method. Inside the method, we will create a ModelAndView object which has the redirecting page(helloWorld) and user passes a String which will be used on the view page.
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;
public class HelloWorldController extends AbstractController
{
@Override
protected ModelAndView handleRequestInternal(HttpServletRequest request,
HttpServletResponse response) throws Exception {
System.out.println("Inside HelloWorldController");
ModelAndView model = new ModelAndView("helloWorld");
model.addObject("msg", "JavaInterviewPoint");
return model;
}
}
WelcomeController.java
WelcomeController is almost the same as HelloWorldController except the redirecting page and the String passed.
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;
public class WelcomeController extends AbstractController
{
@Override
protected ModelAndView handleRequestInternal(HttpServletRequest request,
HttpServletResponse response) throws Exception {
System.out.println("Inside WelcomeController");
ModelAndView model = new ModelAndView("welcome");
model.addObject("msg", "JavaInterviewPoint");
return model;
}
}
helloWorld.jsp
<%@ 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>Insert title here</title>
</head>
<body>
<h2>Hello World ${msg}</h2>
</body>
</html>
welcome.jsp
<%@ 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>Insert title here</title>
</head>
<body>
<h2> Welcome to ${msg}</h2>
</body>
</html>
web.xml
The web.xml has everything about the application that a server needs to know, which is placed under the WEB-INF directory. <servlet-name> contains the name of the SpringConfiguration, when the DispatcherServlet is initialized the framework will try to load a configuration file “[servlet-name]-servlet.xml” under the WEB-INF directory.
<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 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>SpringMVCFormHandling</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>SpringConfig</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>SpringConfig</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
SpringConfig-servlet.xml
- The SpringConfig-servlet.xml is also placed under the WEB-INF directory.
- Here we have configured BeanNameUrlHandlerMapping as the HandlerMapping
- Each request is mapped to a Controller as well
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
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
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
<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.handler.BeanNameUrlHandlerMapping"/>
<bean name="/helloWorld.htm"
class="com.javainterviewpoint.HelloWorldController" />
<bean name="/hello*"
class="com.javainterviewpoint.HelloWorldController" />
<bean name="/welcome.htm"
class="com.javainterviewpoint.WelcomeController"/>
</beans>
In the above example where ever
- helloWorld.htm is requested, the DispatcherServlet redirects it to the HelloWorldController.
- hello123 is requested, the DispatcherServlet redirects it to the HelloWorldController.
- welcome.htm is requested, the DispatcherServlet redirects it to the WelcomeController.
- welcome123 is requested, you will get 404 error as there is no mapping for it.
Output
when HelloWorldController called
Hello World JavaInterviewPoint
when WelcomeController called
Welcome to JavaInterviewPoint
venkatesh says
i am learning spring mvc from your site, but while i am run this application i am getting bellow errore ,but there is no red marks in my code,but my code not execute, i am using latest jar files what ever you mention.
HTTP Status 404 – /SpringMVCHandlerMapping1/
——————————————————————————–
type Status report
message /SpringMVCHandlerMapping1/
description The requested resource is not available.
SEVERE: IOException while saving persisted sessions: java.io.FileNotFoundException: C:\Users\p\Downloads\Workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp1\work\Catalina\localhost\Spring_mvc\SESSIONS.ser (The system cannot find the path specified)
java.io.FileNotFoundException: C:\Users\p\Downloads\Workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp1\work\Catalina\localhost\Spring_mvc\SESSIONS.ser (The system cannot find the path specified)
at java.io.FileOutputStream.open0(Native Method)
at java.io.FileOutputStream.open(FileOutputStream.java:270)
at java.io.FileOutputStream.(FileOutputStream.java:213)
at java.io.FileOutputStream.(FileOutputStream.java:101)
at org.apache.catalina.session.StandardManager.doUnload(StandardManager.java:501)
at org.apache.catalina.session.StandardManager.unload(StandardManager.java:470)
at org.apache.catalina.session.StandardManager.stop(StandardManager.java:679)
at org.apache.catalina.core.StandardContext.stop(StandardContext.java:4886)
at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3458)
at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:426)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1364)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1656)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1665)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1665)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1645)
at java.lang.Thread.run(Thread.java:745)
Feb 08, 2016 7:07:07 PM org.apache.catalina.session.StandardManager stop
SEVERE: Exception unloading sessions to persistent storage
java.io.FileNotFoundException: C:\Users\p\Downloads\Workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp1\work\Catalina\localhost\Spring_mvc\SESSIONS.ser (The system cannot find the path specified)
at java.io.FileOutputStream.open0(Native Method)
at java.io.FileOutputStream.open(FileOutputStream.java:270)
at java.io.FileOutputStream.(FileOutputStream.java:213)
at java.io.FileOutputStream.(FileOutputStream.java:101)
at org.apache.catalina.session.StandardManager.doUnload(StandardManager.java:501)
at org.apache.catalina.session.StandardManager.unload(StandardManager.java:470)
at org.apache.catalina.session.StandardManager.stop(StandardManager.java:679)
at org.apache.catalina.core.StandardContext.stop(StandardContext.java:4886)
at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3458)
at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:426)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1364)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1656)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1665)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1665)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1645)
at java.lang.Thread.run(Thread.java:745)
——————————————————————————–
Apache Tomcat/6.0.44
javainterviewpoint says
Venkatesh
It seems to be a tomcat issue which you used along with eclipse. Try re-installing it and let me know.