spring mvc获取header

两种方法：
1.在方法参数中加入@RequestHeader
2.在类级别注入HttpServletRequest
建议使用第二种方法，这样可避免每个方法都加入HttpHeaders参数

@Controller
@RequestMapping("/hello")
public class HelloController {
     @Autowired
     private HttpServletRequest request;
    
     @RequestMapping(value="/printname/{name}", method=RequestMethod.GET)
     public String printName(@PathVariable String name,
              @RequestHeader HttpHeaders headers) {
          System.out.println("from request:" + request.getHeader("code"));
          System.out.println("from parameter:" + headers.getFirst("code"));
         
          return "hello";
     }
}