12.16 接受请求参数的值

默认方式

直接给方法入参上写一个和请求参数名相同的变量，这个接收请求参数：有值就是有值/ 没值就是null

@RequestMapping("/handle")
public String handle (String username, Model model){
    System.out.println(username);
    model.addAttribute("name",username);
    model.addAttribute("time",System.currentTimeMillis());
    return "success";
}

@RequestMapping("/handle01")
public String handle01 (@RequestParam(value = "user",required = false,defaultValue = "未指定默认值")String username, Model model){
    System.out.println(username);
    model.addAttribute("name",username);
    model.addAttribute("time",System.currentTimeMillis());
    return "success";
}

@RequestParam(“user”)有三个参数：

value 指定要获取的参数key
required 这个参数是否是必须的
defaultValue 默认值

@RequestHeader：获取请求头中的值

- 想获取哪个请求头就获取哪一个 当然是必须存在的，如果不存在的话会报500

@RequestMapping("/handle02")
public String handle02 (@RequestHeader(value = "User-agent") String userAgent, Model model){
    System.out.println(userAgent);
    model.addAttribute("name",userAgent);
    model.addAttribute("time",System.currentTimeMillis());
    return "success";
}

@CookieValue：获取某个Cookie的值

@RequestMapping("/handle03")
public String handle03 (@CookieValue(value = "JSESSIONID") String jid, Model model){
    System.out.println(jid);
    model.addAttribute("name",jid);
    model.addAttribute("time",System.currentTimeMillis());
    return "success";
}

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