轻轻松松学习SpringBoot2：第十五篇：获取访问参数

悠悠 2022-05-21 05:48 371阅读 0赞

一：PathVariable

@RestController
    @RequestMapping("/o")
    public class DemoController {
        @Value("${c}")
        private String c;
        @RequestMapping(value = "/c/{id}",method=RequestMethod.GET)
        String Say(@PathVariable("id") Integer myId){
            return "the id is:"+myId;
        }
    }

或者

@RestController
    @RequestMapping("/o")
    public class DemoController {
        @Value("${c}")
        private String c;
        @RequestMapping(value = "/{id}/c",method=RequestMethod.GET)
        String Say(@PathVariable("id") Integer myId){
            return "the id is:"+myId;
        }
    }

启动服务，执行结果如下

![70][]

![70 1][]

二：RequestParam

@RestController
    @RequestMapping("/o")
    public class DemoController {
        @Value("${c}")
        private String c;
        @RequestMapping(value = "/c",method=RequestMethod.GET)
        String Say(@RequestParam("id") Integer myId){
            return "the id is:"+myId;
        }
    }

执行结果如下

![70 2][]

如果参数不传则会页面报错，这不是我们想看到的，这块我们需要做如下处理

@RestController
    @RequestMapping("/o")
    public class DemoController {
        @Value("${c}")
        private String c;
        @RequestMapping(value = "/c",method=RequestMethod.GET)
        String Say(@RequestParam(value="id",required = false,defaultValue = "999") Integer myId){
            return "the id is:"+myId;
        }
    }

我们默认，如果没有获取到id，则用默认值999代替

![70 3][]

[70]: /images/20220521/0a08e06c89f94c65a61c61ace3b8be1c.png
[70 1]: /images/20220521/02a0dd3a5fcb4cf18a314e6663b035ba.png
[70 2]: /images/20220521/3969437a29ac4e858141bb399a51abb5.png
[70 3]: /images/20220521/e53581689c4647e0b5e0cba91a9f5894.png