Spring Boot中的jQuery AJAX请求上的404

Question

I have recently created a Spring boot project and am trying to work with jQuery AJAX to get data from Controller in Spring. It returns 404 for some reason.

My controller

import java.util.ArrayList;

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

@RestController
public class HomeController {

    @RequestMapping(value="/", method=RequestMethod.GET)
    public String loadHome() {
        return "index";
    }

    @RequestMapping(value="/getMajors", method=RequestMethod.GET)
    public ArrayList<String> getMajors(){
        ArrayList<String> majors = new ArrayList<>();
        majors.add("Computers");
        majors.add("Physics");
        return majors;
    }

}

The first method was to load the home page index.html the second was the method that maps to AJAX request.

My jQuery AJAX Request

$.ajax({
    type:"get",
    url:"/getMajors",
    success:function(data){
        console.log(data);
    },
    error:function(data){
        console.log(data);
    }
});

Please tell me why I'm getting a 404 here. TIA.

Edit: This app was created in Springboot. Standard config with web, dev-tools packages - from spring initializer.

Answer 1

Since you just want to return a data list,so you need to use @ResponseBody to let it only return the data list,change your code like below:

   @RequestMapping(value="/getMajors", method=RequestMethod.GET)
   @ResponseBody
   public ArrayList<String> getMajors(){
        ArrayList<String> majors = new ArrayList<>();
        majors.add("Computers");
        majors.add("Physics");
        return majors;
    }

Also,you need to be aware of ajax get method cache

Answer 2

I guess you are missing two things. One is the context name which usually is the name of the project or the war file deployed to the server, unless you are providing another context in web.xml. A sample servlet mapping from web.xml file:

<servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/*</url-pattern>
</servlet-mapping>

So when your ajax call hits /getMajors it usually points to " localhost:port/getMajors " instead of say " localhost:port/sampleproj/getMajors " .You are missing the context there.

So your method needs to look like this:

@RequestMapping(value = "/getMajors", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
public ArrayList<String> getMajors(){
        ArrayList<String> majors = new ArrayList<>();
        majors.add("Computers");
        majors.add("Physics");
        return majors;
}

One good method to debug these is to see the developer console(Chrome) for request response information.

Happy Coding!

Edit 1 : removing @ResponseBody from method as the class is annotated with @RestController. But my statement stands correct in case the class is annotated with @Controller.