• 表单提交会带上 _method=PUT
    • 请求过来被 HiddenHttpMethodFilter 拦截
      • 请求是否正常，并且是 POST
      • 获取到 _method 的值。
      • 兼容以下请求；PUT.DELETE.PATCH
      • 原生request（post），包装模式requesWrapper重写了getMethod方法，返回的是传入的值。
      • 过滤器链放行的时候用wrapper。以后的方法调用getMethod是调用requesWrapper的。

    [

    ](https://blog.csdn.net/u011863024/article/details/113667634)

    1. public class HiddenHttpMethodFilter extends OncePerRequestFilter {
    3.     private static final List<String> ALLOWED_METHODS =
    4.             Collections.unmodifiableList(Arrays.asList(HttpMethod.PUT.name(),
    5.                     HttpMethod.DELETE.name(), HttpMethod.PATCH.name()));
    7.     /** Default method parameter: {@code _method}. */
    8.     public static final String DEFAULT_METHOD_PARAM = "_method";
    10.     private String methodParam = DEFAULT_METHOD_PARAM;
    13.     /**
    14.      * Set the parameter name to look for HTTP methods.
    15.      * @see #DEFAULT_METHOD_PARAM
    16.      */
    17.     public void setMethodParam(String methodParam) {
    18.         Assert.hasText(methodParam, "'methodParam' must not be empty");
    19.         this.methodParam = methodParam;
    20.     }
    22.     @Override
    23.     protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
    24.             throws ServletException, IOException {
    26.         HttpServletRequest requestToUse = request;
    28.         if ("POST".equals(request.getMethod()) && request.getAttribute(WebUtils.ERROR_EXCEPTION_ATTRIBUTE) == null) {
    29.             String paramValue = request.getParameter(this.methodParam);
    30.             if (StringUtils.hasLength(paramValue)) {
    31.                 String method = paramValue.toUpperCase(Locale.ENGLISH);
    32.                 if (ALLOWED_METHODS.contains(method)) {
    33.                     requestToUse = new HttpMethodRequestWrapper(request, method);
    34.                 }
    35.             }
    36.         }
    38.         filterChain.doFilter(requestToUse, response);
    39.     }
    42.     /**
    43.      * Simple {@link HttpServletRequest} wrapper that returns the supplied method for
    44.      * {@link HttpServletRequest#getMethod()}.
    45.      */
    46.     private static class HttpMethodRequestWrapper extends HttpServletRequestWrapper {
    48.         private final String method;
    50.         public HttpMethodRequestWrapper(HttpServletRequest request, String method) {
    51.             super(request);
    52.             this.method = method;
    53.         }
    55.         @Override
    56.         public String getMethod() {
    57.             return this.method;
    58.         }
    59.     }
    61. }
    • Rest使用客户端工具。
      • 如PostMan可直接发送put、delete等方式请求。