Spring MVC exception handling tutorial

Let us discuss spring mvc exception handling example in eclipse.

Example Explanation:

Use http://localhost:8080/SpringMVCExample6/ student url to start the application. A request for respective resource will generate. Request will be handled by DispatcherServlet. It delegates the request to the ExceptionHandlingController controller. The LoginController controller resolve the request with help of RequestMapping annotation, executes the specific functionality and returns the ModelAndView object to the DispatcherServlet. The DispatcherServlet then take the help of InternalResourceViewResolver to get the actual view name. In our example it will return the “/WEB-INF/jsp/student.jsp. The DispatcherServlet then insert the model data into view and render response. Same request response cycle will execute when we click on submit button after entering the student details.

Note: The @ExceptionHandler annotation is used to specify the exception handlers. Use comma separated handlers if more than one exceptions are specified.

Example:

student.jsp

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>

  
    
  
  
  

   

    

        
Name
        

    
    

        
Class
        

    
    

        
RollNo
        

    
    

        

            
        
    
  

web.xml

  

   
   
      ExceptionHandling
      
         org.springframework.web.servlet.DispatcherServlet
      
      1
   

   
      ExceptionHandling
      /
   
 

ExceptionHandling-servlet.xml

  


   

  
      
      
   
   
  
   
      
         
            exceptionpage
         
      
   
   
  

Student.java

public class Student {
	private String name;
	private String className;
	private String rollNo;
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getClassName() {
		return className;
	}
	public void setClassName(String className) {
		this.className = className;
	}
	public String getRollNo() {
		return rollNo;
	}
	public void setRollNo(String rollNo) {
		this.rollNo = rollNo;
	}
	
}

SpringException.java

public class SpringException extends RuntimeException{
   private String exceptionMsg;
   
   public SpringException(String exceptionMsg) {
      this.exceptionMsg = exceptionMsg;
   }
   
   public String getExceptionMsg(){
      return this.exceptionMsg;
   }
   
   public void setExceptionMsg(String exceptionMsg) {
      this.exceptionMsg = exceptionMsg;
   }
}

ExceptionHandlingController.java

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
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 ExceptionHandlingController {
   @RequestMapping(value = "/student", method = RequestMethod.GET)
   public ModelAndView student() {
      return new ModelAndView("student", "command", new Student());
   }
   
   @RequestMapping(value = "/addStudent", method = RequestMethod.POST)
   @ExceptionHandler({SpringException.class})
   public String addStudent(@ModelAttribute("SpringWeb")Student student, 
   ModelMap model) {
      if(student.getName().length() < 5 ){
         throw new SpringException("Student name should " +
         		"contain atleast 5 characters.");
      }else{
    	  model.addAttribute("name", student.getName());
      }
      
      model.addAttribute("className", student.getClassName());     
      model.addAttribute("rollNo", student.getRollNo());
      
      return "welcome";
   }
}

welcome.jsp

  
    
  
  
    
Student Details
    

    

        
Name
        
${name}
    
    

        
Class
        
${className}
    
    

        
RollNo
        
${rollNo}
    
   
  
  

exceptionpage.jsp

  
    
  
  
   
${exception.exceptionMsg}
  

error.jsp

  
    
  
  
   
Unknown exception.
  

Output:

Enter username with < 5 characters.

Click on Submit button.

 
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