2小時學會SpringBoot(4-1)

Controller的使用

Controller	處理http請求
@RestController	Spring4之後新加的註解，原來json需要@ResponseBody配合@Controller
@RequestMapping	配置url映射

thymeleaf瞭解一下即可，現在的開發方式都是前後端分離的。
@RestController等同於@Controller和@ResponseBody

如果希望訪問 http://127.0.0.1:8080/hi 和 http://127.0.0.1:8080/hello 都可以訪問到 /hello 接口。在這裏需要寫成集合。

@RequestMapping(value = {"/hello","hi"},method = RequestMethod.GET)

@RequestMapping還有一種使用方式是給整個類使用。

package com.fiona;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/hello")
public class HelloController {

    @Autowired
    private GirlProperties girlProperties;

    @RequestMapping(value = "/say",method = RequestMethod.GET)
    public String say() {
        return girlProperties.getCupSize();
    }
}

如果要使用除Get以外的其他方式，常用的是Get和Post。改成post請求

@RestController
@RequestMapping("/hello")
public class HelloController {

    @Autowired
    private GirlProperties girlProperties;

    @RequestMapping(value = "/say",method = RequestMethod.POST)
    public String say() {
        return girlProperties.getCupSize();
    }
}

瀏覽器訪問 http://127.0.0.1:8080/hello/say 報405。使用postman選擇post方法進行請求。

不寫請求方式，Get和Post均可訪問到，但不推薦。爲了安全起見。

@RequestMapping(value = "/say")

@PathVariable	獲取url中的數據
@RequestParam	獲取請求參數的值
@GetMapping	組合註解

@RestController
@RequestMapping("/hello")
public class HelloController {

    @RequestMapping(value = "/say/{id}",method = RequestMethod.GET)
    public String say(@PathVariable("id") Integer id) {
        return "id:"+id;
    }
}

瀏覽器訪問 http://127.0.0.1:8080/hello/say/23
顯示 id:23

@RestController
@RequestMapping("/hello")
public class HelloController {

    @RequestMapping(value = "/{id}/say",method = RequestMethod.GET)
    public String say(@PathVariable("id") Integer id) {
        return "id:"+id;
    }
}

瀏覽器請求 http://127.0.0.1:8080/hello/100/say
顯示 id:100

@RestController
@RequestMapping("/hello")
public class HelloController {

    @RequestMapping(value = "/say",method = RequestMethod.GET)
    public String say(@RequestParam("id") Integer id) {
        return "id:"+id;
    }
}

瀏覽器請求 http://127.0.0.1:8080/hello/say?id=50
顯示 id:50
@RequestParam(“id”)引號裏面的名字要和瀏覽器的變量名一致，但後面但id可以不叫id，取其他名字也可以。

@RestController
@RequestMapping("/hello")
public class HelloController {

    @RequestMapping(value = "/say",method = RequestMethod.GET)
    public String say(@RequestParam("id") Integer myId) {
        return "id:"+myId;
    }
}

瀏覽器請求 http://127.0.0.1:8080/hello/say?id=111
顯示 id:111

假如不傳id

給id設定一個默認值爲0

@RestController
@RequestMapping("/hello")
public class HelloController {

    @RequestMapping(value = "/say",method = RequestMethod.GET)
  public String say(@RequestParam(value = "id" ,required = false , defaultValue = "0") Integer id) {
        return "id:"+id;
    }
}

可以使用

@GetMapping(value = "/say")

代替

@RequestMapping(value = "/say",method = RequestMethod.GET)

還有 @PostMapping @PutMapping這樣的組合書寫。