Dinesh on Java

In this example show how to write a simple web based application using Spring MVC Framework, which can handle one or more exceptions raised inside its controllers. To start with it, let us have working STS IDE in place and follow the following steps to develop a Dynamic Form based Web Application using Spring Web Framework:

Step 1: Create a Dynamic Web Project with a name SpringMVCExecptionApp and create a package com.dineshonjava.controller under the src folder in the created project.

Step 2: Add below mentioned Spring 3.0 libraries and other libraries into the folder WebRoot/WEB-INF/lib. 

• commons-logging-1.1.1.jar
• org.springframework.asm-3.0.0.jar
• org.springframework.beans-3.0.0.jar
• org.springframework.context-3.0.0.jar
• org.springframework.core-3.0.0.jar
• org.springframework.expression-3.0.0.jar
• org.springframework.web.servlet-3.0.0.jar
• org.springframework.web-3.0.0.jar
• spring-web.3.0.0.jar

 Step 3: Create a Java class EmployeeController and Employee under the com.dineshonjava.controller com.dineshonjava.bean package respectively.

Step 4: Create Spring configuration files Web.xml and sdnext-servlet.xml under the WebRoot/WEB-INF/ folder.

Step 5: Create a sub-folder with a name views under the WebRoot/WEB-INF folder. Create a view file employeeForm.jsp and employeeDetail.jsp under this sub-folder.

Step 6: The final step is to create the content of all the source and configuration files name sdnext-servlet.xml under the sub-folder WebRoot/WEB-INF/config and export the application as explained below.

Software versions used to run the sample code:

• Spring 3.0
• Java 1.6
• Tomcat 7
• JSTL 1.2
• STS Java EE IDE

                                                Web Application Structure:

  Employee.java

package com.dineshonjava.emp.bean;

/**
 * @author Dinesh Rajput
 *
 */
public class Employee {
 private int empId;
 private String name;
 private Long salary;
 private int age;
 /**
  * @return the empId
  */
 public int getEmpId() {
  return empId;
 }
 /**
  * @param empId the empId to set
  */
 public void setEmpId(int empId) {
  this.empId = empId;
 }
 /**
  * @return the name
  */
 public String getName() {
  return name;
 }
 /**
  * @param name the name to set
  */
 public void setName(String name) {
  this.name = name;
 }
 /**
  * @return the salary
  */
 public Long getSalary() {
  return salary;
 }
 /**
  * @param salary the salary to set
  */
 public void setSalary(Long salary) {
  this.salary = salary;
 }
 /**
  * @return the age
  */
 public int getAge() {
  return age;
 }
 /**
  * @param age the age to set
  */
 public void setAge(int age) {
  this.age = age;
 }
 
 public String toString(){
  return "Employee{ name-"+name+" age-"+age+" salary-"+salary+"}";
 }
}

EmployeeException.java

package com.dineshonjava.emp.exception;

/**
 * @author Dinesh Rajput
 *
 */
public class EmployeeException extends RuntimeException {

 private static final long serialVersionUID = -4794572499177930357L;
 
 private String exceptionMsg;
  
 public EmployeeException(String exceptionMsg) {
  this.exceptionMsg = exceptionMsg;
 }
 
 public String getExceptionMsg(){
  return this.exceptionMsg;
 }
 
 public void setExceptionMsg(String exceptionMsg) {
  this.exceptionMsg = exceptionMsg;
 }
}

EmployeeController.java

package com.dineshonjava.emp.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
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;

import com.dineshonjava.emp.bean.Employee;
import com.dineshonjava.emp.exception.EmployeeException;

/**
 * @author Dinesh Rajput
 *
 */
@Controller
public class EmployeeController {
 
 @RequestMapping(value = "/employee", method = RequestMethod.GET)
 public ModelAndView employee() {
  return new ModelAndView("employeeForm", "command", new Employee());
 }
    
 @RequestMapping(value = "/addEmployee", method = RequestMethod.POST)
 public String addEmployee(@ModelAttribute("SpringWeb")Employee employee, ModelMap model) {
  
      if(employee.getName().length() < 5 ){
          throw new EmployeeException("Given name is too short");
     }else{
      model.addAttribute("name", employee.getName());
     }
     if( employee.getAge() < 10 ){
  throw new EmployeeException("Given age is too low");
     }else{
  model.addAttribute("age", employee.getAge());
     }
     model.addAttribute("empId", employee.getEmpId());
     model.addAttribute("salary", employee.getSalary());
     return "employeeDetail";
 }
}

Spring Web configuration file web.xml

<web-app id="WebApp_ID" version="3.0" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 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">

  <display-name>SpringMVCExceptionApp</display-name>
  <welcome-file-list>
  <welcome-file>/</welcome-file>
 </welcome-file-list>
 
    <servlet>
        <servlet-name>sdnext</servlet-name>
        <servlet-class>
            org.springframework.web.servlet.DispatcherServlet
        </servlet-class>
      <init-param>
            <param-name>contextConfigLocation</param-name><param-value>/WEB-INF/config/sdnext-servlet.xml</param-value></init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>sdnext</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

Spring Web configuration file sdnext-servlet.xml

<beans xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:p="http://www.springframework.org/schema/p" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" 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">

<!-- Enable annotation driven controllers, validation etc... -->
<mvc:annotation-driven></mvc:annotation-driven>

<context:component-scan base-package="com.dineshonjava.emp.controller">
</context:component-scan>

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="viewResolver">
 <property name="prefix" value="/WEB-INF/views/"></property>
 <property name="suffix" value=".jsp"></property>
</bean>
 
<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
    <property name="exceptionMappings">
         <props>
            <prop key="com.dineshonjava.emp.exception.EmployeeException">
             ExceptionPage
            </prop>
         </props>
    </property>
    <property name="defaultErrorView" value="error"></property>
</bean>
 
</beans>

Here you specified ExceptionPage as an exception view in case EmployeeException occurs, if there is any other type of exception then a generic view error will take place.
employeeForm.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"%>

<html>
 <head>
  
  <title>Spring MVC Form Handling</title>
 </head>
 &body>
Employee Data Form
<form:form action="/sdnext/addEmployee" method="POST">      
<table><tbody>
<tr>        <td><form:label path="empId">Employee :</form:label></td>      <td><form:input path="empId"></form:input></td>    </tr>
<tr>      <td><form:label path="name">EmployeeName:/form:label&gt;</form:label></td>       <td><form:input path="name"></form:input></td>    </tr>
<tr>       <td><form:label path="age">Employee Age:</form:label></td>       <td><form:input path="age"></form:input></td>     </tr>
<tr>      <td><form:label path="salary">Employee Salary:</form:label></td>     <td><form:input path="salary"></form:input></td>    </tr>
<tr>         <td colspan="2">&lt;input type="submit" value="Submit"/&gt;  </td>       </tr>
</tbody></table>
</form:form>
</body>
</html>

employeeDetail.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"%>

<html>
   <head>
 <title>Spring MVC Form Handling</title>
   </head>
<body>
<h2>
Submitted Employee Information</h2>
<table border="1"><tbody>
<tr>     <td>Employee ID </td>      <td>${empId}</td>   </tr>
<tr>      <td>Employee Name</td>      <td>${name}</td>  </tr>
<tr>     <td>Employee Age</td>      <td>${age}</td>     </tr>
<tr>      <td>Employee Salary</td>       <td>${salary}</td> </tr>
</tbody></table>
</body>
</html>

ExceptionPage.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>

<html>
<head>

<title>Spring MVC Exception Handling</title>
</head>
<body>
 
Spring MVC Exception Handling
${exception.exceptionMsg}
</body>
</html>

error.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>

<html>
<head>
    <title>Spring Error Page</title>
</head>
<body>

An error occurred, please contact dineshonjava at admin@dineshonjava.com
</body>
</html>

Once you are done with creating source and configuration files, export your application. Right click on your application and use Export-> WAR File option and save your SpringExceptionApp.war file in Tomcat’s webapps folder.

Now start your Tomcat server and make sure you are able to access other web pages from webapps folder using a standard browser. Now try a URL http://localhost:8080/sdnext/employee and you should see the following result if everything is fine with your Spring Web Application:

 After submitting required information click on submit button to submit the form. You should see the following result if everything is fine with your Spring Web Application:

 Now enter the age to low the see what happens.

 After submitting required information click on submit button to submit the form. You should see the following result if everything is fine with your Spring Web Application:

 If every thing is ok what ever we enter into the employee form then after submitting for we will find the following output:

 If we submit such data into form which give exception beyond the EmployeeException then we will get the following output:

 If every thing is ok then after submitting for we will find the following output:

Download Source code
SpringMVCExecptionApp.zip