IDEA版SSM入门到实战（Maven+MyBatis+Spring+SpringMVC) -SpringMVC REST【RESTful】风格CRUD

第一章 REST【RESTful】风格CRUD

1.1 REST的CRUD与传统风格CRUD对比

• 传统风格CRUD

  • 功能 URL 请求方式
  • 增 /insertEmp POST
  • 删 /deleteEmp?empId=1001 GET
  • 改 /updateEmp POST
  • 查 /selectEmp?empId=1001 GET

• REST风格CRUD

  • 功能 URL 请求方式
  • 增 /emp POST
  • 删 /emp/1001 DELETE
  • 改 /emp PUT
  • 查 /emp/1001 GET

1.2 REST风格CRUD优势

• 提高网站排名
  • 排名方式
    • 竞价排名
    • 技术排名
• 便于第三方平台对接

1.3 实现PUT&DELETE提交方式步骤

• 注册过滤器HiddenHttpMethodFilter
• 设置表单的提交方式为POST
• 设置参数：_method=PUT或_method=DELETE

1.4 源码解析HiddenHttpMethodFilter

public static final String DEFAULT_METHOD_PARAM = "_method";

private String methodParam = DEFAULT_METHOD_PARAM;

@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
      throws ServletException, IOException {

   HttpServletRequest requestToUse = request;

   if ("POST".equals(request.getMethod()) && request.getAttribute(WebUtils.ERROR_EXCEPTION_ATTRIBUTE) == null) {
      String paramValue = request.getParameter(this.methodParam);
      if (StringUtils.hasLength(paramValue)) {
         String method = paramValue.toUpperCase(Locale.ENGLISH);
         if (ALLOWED_METHODS.contains(method)) {
            requestToUse = new HttpMethodRequestWrapper(request, method);
         }
      }
   }

   filterChain.doFilter(requestToUse, response);
}
/**
	 * Simple {@link HttpServletRequest} wrapper that returns the supplied method for
	 * {@link HttpServletRequest#getMethod()}.
	 */
	private static class HttpMethodRequestWrapper extends HttpServletRequestWrapper {

		private final String method;

		public HttpMethodRequestWrapper(HttpServletRequest request, String method) {
			super(request);
			this.method = method;
		}

		@Override
		public String getMethod() {
			return this.method;
		}
	}