Spring MVC cannot find *.jsp files

Question

I am an absolute noob when it comes to web development. But I got some background in C/C++/Java so I don't have a problem with MVC controllers. It's the configuration that is giving me the headache.

I am using Spring Boot. And according to the tutorials it can magically resolve everything without even opening an editor and typing a single character. Apparently not.

I have a view resolver configure as such:

@Configuration
@ComponentScan (basePackages = {"my.test.controller"})
@EnableAutoConfiguration
public class WebConfig extends WebMvcConfigurerAdapter {
    @Override
  public void addResourceHandlers(ResourceHandlerRegistry registry) {
       registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
  }

@Bean
    public InternalResourceViewResolver getViewResolver(){
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setViewClass(JstlView.class);
        viewResolver.setPrefix("/WEB-INF/views/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
   }



   public static void main(String[] args) throws Exception {
       SpringApplication.run(WebConfig.class, args);
   }

}

I have a controller like this:

@Controller
public class PageController {

@RequestMapping(value = "/index")
public String doSomething() {

        //.. do Something

        return "/index";
    }

My main problem is it cannot find the file if there is a jsp extension in the address. If I type the url without an extension like localhost:8080/index the page is displayed properly. If I type the url with an extension like localhost:8080/index.jsp the page returns a 404 error. This is the same for all pages declared in the controller.

Any help will be greatly appreciated. Thanks thanks.

Answer 1

There's a JSP sample in Spring Boot that you can crib from. If I were you I wouldn't define a ViewResolver since Boot already does that for you (but if you want to use prefix and suffix resolution you need to set spring.view.prefix and spring.view.suffix).

Your @Controller should return view names (not paths), so "index" is going to be resolved as "/WEB-INF/views/index.jsp" with your existing setup. I also wouldn't bother with the "/resources" mapping since one is already provided by Spring Boot, albeit a different one than you defined (normally people put static resources in "classpath:/static" but "classpath:/resources" works as well and there is no prefix for the path to the resource in the HTTP endpoints).

JSP is inferior to other view technologies in so many ways, so it is unfortunate that it is so ubiquitous. There are many limitations, including restrictions on the way you can package and run a Boot application (see here for details). It would be worth your effort to unlearn JSP if you can spare the time.

Answer 2

I remember having the same problem when I started with spring, the "url" that you use needs to correspond to a particular Request Mapping, not necessarily a particular page for example

@RequestMapping(value = "/home")
public String doSomething() {

    //.. do Something

    return "/index";
}

will expose an endpoint at localhost:8080/home not localhost:8080/index or localhost:8080/index.jsp

A great example project is located at: https://github.com/mariuszs/spring-boot-web-jsp-example