We have learnt how to handle exception using the Spring exception handling mechanism through my previous articles and we know how the @ControllerAdvice and @ExceptionHandler annotations works, how to handle exception globally. Now let’s see how do we handle a User Defined Exception.
Folder Structure :
- Create a Dynamic Web Project RegistrationForm 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 - Put the index.jsp under the WebContent directory.
- Create the Java classes RegistrationController.java, GlobalException.java, UserDefinedException.java and RegistrationBean.java under com.javainterviewpoint folder.
- Place the SpringConfig-servlet.xml and web.xml under the WEB-INF directory
- View files RegistrationForm.jsp and exceptionPage.jsp are put under the sub directory under WEB-INF/Jsp
UserDefinedException.java
package com.javainterviewpoint;
public class CustomException extends RuntimeException
{
String message;
String name;
public CustomException(String message,String name)
{
this.message=message;
this.name=name;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
Create our own UserDefinedException class which extends RuntimeException, with two attributes such as name and message. So that we can pass the Custom name and Custom message which can be used to display to the user.
GlobalException.java
package com.javainterviewpoint;
import java.io.IOException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.ModelAndView;
@ControllerAdvice
public class GlobalException
{
@ExceptionHandler(IOException.class)
public ModelAndView processIOException(IOException ioe)
{
ModelAndView mav = new ModelAndView("exceptionPage");
mav.addObject("name", ioe.getClass().getSimpleName());
mav.addObject("message", ioe.getMessage());
return mav;
}
@ExceptionHandler(UserDefinedException.class)
public ModelAndView processCustomException(UserDefinedException ud)
{
ModelAndView mav = new ModelAndView("exceptionPage");
mav.addObject("name", ud.getName());
mav.addObject("message", ud.getMessage());
return mav;
}
}
Here the processCustomException() will handle the UserDefinedException when occurred, it will also redirect the user to the exceptionPage.
RegistrationController.java
package com.javainterviewpoint;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.validation.Valid;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
@Controller
public class RegistrationController
{
@ModelAttribute("professionList")
public List populateProfessionList()
{
List professionList = new ArrayList();
professionList.add("Devloper");
professionList.add("Manager");
professionList.add("Architecht");
return professionList;
}
@ModelAttribute("hobbyList")
public List populateHobbyList()
{
List hobbyList = new ArrayList();
hobbyList.add("Cricket");
hobbyList.add("Football");
hobbyList.add("Hockey");
hobbyList.add("Basketball");
return hobbyList;
}
@RequestMapping("/dispForm")
public String displayForm(Map model)
{
RegistrationBean rb = new RegistrationBean();
model.put("rb",rb);
return "registrationForm";
}
@RequestMapping(value="/register",method=RequestMethod.POST)
public String processRegistration(@ModelAttribute("rb") RegistrationBean rb) throws IOException
{
if(rb.getFirstName().length()>5)
{
throw new IOException("IOException has occured");
}
if(rb.getLastName().length()>5)
{
throw new UserDefinedException("Custom Exception has occured", "CustomException");
}
return "success";
}
}
Our RegistrationController class will throw two exceptions
1. When the firstName is greater than 5 it will throw IOException
2. When the lastName is greater than 5 it will throw CustomException
Both the exceptions will be handled globally by our GlobalException class.
exceptionPage.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>
<h3 style="color: red">Ops!! Something went wrong!</h3>
<h5 style="color: red">${name}</h5><br>
<h5 style="color: red">${message}</h5>
</body>
</html>
This page will be rendered to the user when exception occurs.
Index.jsp
This is simply a start-up page which redirects the user to our RegistrationForm.
<%@ 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> <a href="displayForm.html">Click here to Register</a> </body> </html>
RegistrationForm.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form" %>
<!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>
<form:form action="register" method="post" commandName="rb">
<table>
<tr><td>First Name</td><td><form:input path="firstName"/></td></tr>
<tr><td>Last Name</td><td><form:input path="lastName"/></td></tr>
<tr><td>Email</td><td><form:input path="email"/></td></tr>
<tr><td>Profession</td><td><form:select path="profession" items="${professionList}"></form:select></td><td></td></tr>
<tr><td>Hobby</td><td><form:checkboxes items="${hobbyList}" path="hobby"/></td></tr>
<tr><td></td><td><input type="submit" value="Register"></td></tr>
</table>
</form:form>
</body>
</html>
RegistraionBean.java
package com.javainterviewpoint;
public class RegistrationBean
{
String firstName;
String lastName;
String email;
String profession;
String[] hobby;
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getProfession() {
return profession;
}
public void setProfession(String profession) {
this.profession = profession;
}
public String[] getHobby() {
return hobby;
}
public void setHobby(String[] hobby) {
this.hobby = hobby;
}
}
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" 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_3_0.xsd" id="WebApp_ID" version="3.0"> <servlet> <servlet-name>SpringConfig</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>SpringConfig</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
Spring Configuration File
<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"> <context:component-scan base-package="com.javainterviewpoint"></context:component-scan> <mvc:annotation-driven/> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/Jsp/"></property> <property name="suffix" value=".jsp"></property> </bean> </beans>
Let’s Run our application
Enter any value in the firstName or lastName field greater than 5 character length and submit the form.
http://localhost:8080/Spring_MVC_ExceptionHandler/
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