What is the use of @ModelAttribute annotation?



In this quick article, we will discuss one important Spring MVC interview question that is what is the use of @ModelAttribute annotation

What is the use of @ModelAttribute annotation?

The @ModelAttribute annotation is one of the most important annotations in Spring MVC. It binds a method parameter or a method return value to a named model attribute and then exposes it to a web view.

@ModelAttribute can be used either as a method parameter or at the method level.

At the Method Level

When the annotation is used at the method level it indicates the purpose of that method is to add one or more model attributes.
@ModelAttribute
public void addAttributes(Model model) {
    model.addAttribute("msg", "Hello World");
}
@ModelAttribute methods are invoked before the controller methods annotated with @RequestMapping are invoked.

As a Method Argument

When used as a method argument, it indicates the argument should be retrieved from the model.

For example, the employee form data will be bound to Employee bean using @ModelAttribute annotation:

@RequestMapping(value = "/addEmployee", method = RequestMethod.POST)
public String submit(@ModelAttribute("employee") Employee employee) {
    // Code that uses the employee object

    return "employeeView";
}

References

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