Multiple Request Mappings in Spring Boot

In this tutorial, we are taking a look at a student's question from my Spring Boot Introduction Course. The question was related to building out Spring Controllers and how to define multiple request mappings for a single method.

"How can I create multiple request mappings for a single method?"

Multiple Request Mappings

If you want to follow along with this tutorial you can create a simple Spring Boot project that includes the Web dependency. We know that we can use the @RequestMapping annotation to map web requests onto specific handler classes and/or handler methods. If we wanted to map our home method to the root "/" we can do so using the following code. 

package com.therealdanvega;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HomeController {

    @RequestMapping("/")
    public String home() {
        return "Hello, World!";
    }

}

If you fire up this application and visit http://localhost:8080/ you will see the string "Hello, World!" returned to the browser. What happens if you wanted to define 2 or more web requests to be handled by the same method? It turns out you can only use one annotation per method, so something like this will not work. 

package com.therealdanvega;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HomeController {

    @RequestMapping("/")
    @RequestMapping("/home")
    public String home() {
        return "Hello, World!";
    }

}

If we look at the Request Mapping class value will take an array of strings and defaults to an empty array.

@AliasFor("value")
String\[\] path() default {};

So we can pass in an array of strings that represent web requests. 

package com.therealdanvega;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HomeController {

    @RequestMapping( {"/", "/home"} )
    public String home() {
        return "Hello, World!";
    }

}

Now if visit http://localhost:8080/ or http://localhost:8080/home  we should see the string "Hello, World!" printed to the browser window. 

Multiple Request Mappings Screencast

https://www.youtube.com/watch?v=qmALVM38oec&t=1s

Conclusion

There are some things that might not be apparent but as we saw in this tutorial we can quickly drill into the code and find a solution. This is one of the many reasons open source is so great.

Question: Do you face any problems setting up request mappings?