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
February 8, 2016 at 7:19 pmi 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
February 9, 2016 at 9:49 amVenkatesh
It seems to be a tomcat issue which you used along with eclipse. Try re-installing it and let me know.