[JAVA] ◆ Try calling SpringBoot + gradle REST + JSON format API

★ Introduction

I forgot to write the Java version in the environment construction memo. It will be Java 8. This article is also a memo for myself.

★ HelloWorld Since it is the first time, I will try it by displaying "Hello World" on the screen. The package structure is as follows.

Create ʻappas an application layer in the same hierarchy as SampleProjectApplication.java. Furthermore,controller` is created under it.

RestApiController.java

package com.example.sample.app.controller;

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

@RestController
@RequestMapping("api/sample")
public class RestApiController {

    @RequestMapping(value = "/hello")
    public String index() {
        return "Hello World!";
    }
}

Right-click on the project ⇒ [Run] ⇒ [4 Spring Boot Application]. The log is output to the console.

Go to http: // localhost: 8080 / api / sample / hello.

It was displayed safely.

It is described in () of @ RequestMapping, but it seems OK to omit value or describe it as path.

★ Implementation of HTTP method

The HTTP method is GET, and when thrown, it implements a method that returns the information of the birthday stone (month, name, color). RequestMethod of @ RequestMapping specifies GET.

RestApiController.java

package com.example.sample.app.controller;

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

import com.example.sample.app.resource.BirthStone;

@RestController
@RequestMapping("api/sample")
public class RestApiController {

    @RequestMapping(value = "/getBirthStone", method = RequestMethod.GET)
    @ResponseBody
    public BirthStone getBirthStone() {
        BirthStone birthStone = new BirthStone("February", "amethyst", "purple");
        return birthStone;
    }
}

Create a resource under ʻapp and a BirthStone class` to return the birthday stone information.

BirthStone.java

package com.example.sample.app.resource;

import java.io.Serializable;

public class BirthStone implements Serializable {

    private static final long serialVersionUID = 1L;

    /**Month*/
    private String month;

    /**name*/
    private String name;

    /**color*/
    private String color;

    public BirthStone (String month, String name, String color) {
        this.month = month;
        this.name = name;
        this.color = color;
    }
    
    // getter/setter description omitted
}

The result of calling the API in the Advanced REST Client.

I got a response.

If the HTTP method is POST, write RequestMethod = POST.