What is ViewResolver in Spring MVC and how does it work?

Question

Accepted Answer

A ViewResolver in Spring MVC translates the logical view name a controller returns into an actual view object that can render a response, keeping controllers unaware of the concrete rendering technology.

Key Points:
• Controllers return a plain String or a ModelAndView carrying just a view name, like "home", not a file path.
• InternalResourceViewResolver applies a configured prefix and suffix, so "home" becomes /WEB-INF/views/home.jsp.
• The resolved View object is then handed the model data and asked to render the response.
• This indirection decouples controller logic from the view technology, so you can swap JSP for Thymeleaf without touching controllers.
• Multiple resolvers can be registered with priority ordering when an app mixes view technologies.

Example:
A controller method returning "userProfile" combined with a prefix of /WEB-INF/views/ and a suffix of .jsp resolves to /WEB-INF/views/userProfile.jsp, which Spring then forwards the request to for rendering.

Code Example:
```
@Bean
public ViewResolver viewResolver() {
    InternalResourceViewResolver resolver = new InternalResourceViewResolver();
    resolver.setPrefix("/WEB-INF/views/");
    resolver.setSuffix(".jsp");
    return resolver;
}
```

Interview Tip:
A concise interview answer is:

"A ViewResolver takes the logical view name a controller returns and maps it to an actual view file, usually by combining a configured prefix and suffix. This keeps controllers decoupled from the rendering technology — the controller just says 'home', and the resolver figures out that means /WEB-INF/views/home.jsp."