SpringBoot 第三天——@RestController、@RequestMapping、@PathVariable、@RequestPaeam、@GetMapping的使用

s廖师兄，2小时学会Spring Boot 点击打开链接

番外篇：postman软件可以用来模拟发送post和get请求

一、@Controller 和@RestController 两个注解的异同点在第一天的遇到的坑中记录过，这里就不再记录了。

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

如果希望/hello 和 /hi 能匹配同一个方法

    @RequestMapping(value = {"hello", "hi"}, method = RequestMethod.GET)
    public String sayHello() {
        System.out.println("Hello SpringBoot");
        //return "Hello:" + cupSize + ":" + age;
        //return content;
        return girl.getCupSize();
    }

三、@PathVariable

优点：这种写法，url 会很简洁

第一种：参数在最后面

    @RequestMapping(value = "/hello/{id}", method = RequestMethod.GET)
    public String sayHello(@PathVariable("id") Integer myId) {
        System.out.println("Hello SpringBoot");
        //return "Hello:" + cupSize + ":" + age;
        //return content;
        //return girl.getCupSize();
        return "id:" + myId ;
    }

第二种：参数在前面

    @RequestMapping(value = "/{id}/hello", method = RequestMethod.GET)
    public String sayHello(@PathVariable("id") Integer myId) {
        System.out.println("Hello SpringBoot");
        //return "Hello:" + cupSize + ":" + age;
        //return content;
        //return girl.getCupSize();
        return "id:" + myId ;
    }

四、@RequestParam

    需要注意的是：@RequestParam（"id）中的参数 id 要和 url 中一模一样

1、第一种用法

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

2、第二种用法：如果不传就给默认值

    @RequestMapping(value = "/hello", method = RequestMethod.GET)
    public String sayHello(@RequestParam(value = "id", required = false, defaultValue = "99") Integer myId) {
        return "id:" + myId ;
    }

五、@GetMapping

    优点：简化代码。如果是GET请求就用 @GetMapping ，如果是POST请求就用 @PostMapping 

    //@RequestMapping(value = "/hello", method = RequestMethod.GET)
    @GetMapping("/hello")
    public String sayHello(@RequestParam(value = "id", required = false, defaultValue = "99") Integer myId) {
        return "id:" + myId ;
    }