Response JSON

大部份的API都會回傳json 本文介紹一些回傳json的方式

Controller

@Controller
public class HelloworldController {
    @RequestMapping(value = "/returnJson", method = RequestMethod.GET)
    @ResponseBody
    public String returnJson(HttpServletRequest request) throws JSONException {
        JSONObject ret = new JSONObject();
        ret.put("hello", "json");
        return ret.toString();
    }

    @RequestMapping(value = "/returnModel.json", method = RequestMethod.GET, produces="application/json")
    @ResponseBody
    public User returnModel(HttpServletRequest request) throws JSONException {
        User user = new User(1, "welson");
        return user; // auto convert to json
    }
}
class User {
    int id;
    String name;
    public User(int id, String name) {
        this.id = id;
        this.name = name;
    }
}

說明

• 一般mvc的框架在執行完controller後都會進入view的頁面，但如果只想單純回傳資料，請宣告@ResponseBody
• 本例介紹兩種回傳json的方式：
  • (1)@Responsebody為String
  • (2)只要是key/value形式的Class，可以自動回傳json資料。(如本例的User)