请求映射
@xxxMapping;
@GetMapping
@PostMapping
@PutMapping
@DeleteMapping
Rest风格支持（使用HTTP请求方式动词来表示对资源的操作）
以前：
/getUser 获取用户
/deleteUser 删除用户
/editUser 修改用户
/saveUser保存用户
现在： /user
GET-获取用户
DELETE-删除用户
PUT-修改用户
POST-保存用户
核心Filter；HiddenHttpMethodFilter
用法
开启页面表单的Rest功能
页面 form的属性method=post，隐藏域 _method=put、delete等（如果直接get或post，无需隐藏域）
编写请求映射
spring: mvc: hiddenmethod: filter: enabled: true #开启页面表单的Rest功能(默认是false)
<form action="/user" method="get"> <input value="REST-GET提交" type="submit" /> </form> <form action="/user" method="post"> <input value="REST-POST提交" type="submit" /> </form> <form action="/user" method="post"> <input name="_method" type="hidden" value="DELETE"/> <input value="REST-DELETE 提交" type="submit"/> </form> <form action="/user" method="post"> <input name="_method" type="hidden" value="PUT" /> <input value="REST-PUT提交"type="submit" /> <form>
@GetMapping("/user") //@RequestMapping(value = "/user",method = RequestMethod.GET) public String getUser(){ return "GET-张三"; } @PostMapping("/user") //@RequestMapping(value = "/user",method = RequestMethod.POST) public String saveUser(){ return "POST-张三"; } @PutMapping("/user") //@RequestMapping(value = "/user",method = RequestMethod.PUT) public String putUser(){ return "PUT-张三"; } @DeleteMapping("/user") //@RequestMapping(value = "/user",method = RequestMethod.DELETE) public String deleteUser(){ return "DELETE-张三"; }
Rest原理（表单提交要使用REST的时候）
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。
public class HiddenHttpMethodFilter extends OncePerRequestFilter { private static final List<String> ALLOWED_METHODS = Collections.unmodifiableList(Arrays.asList(HttpMethod.PUT.name(), HttpMethod.DELETE.name(), HttpMethod.PATCH.name())); /** Default method parameter: {@code _method}. */ public static final String DEFAULT_METHOD_PARAM = "_method"; private String methodParam = DEFAULT_METHOD_PARAM; /** * Set the parameter name to look for HTTP methods. * @see #DEFAULT_METHOD_PARAM */ public void setMethodParam(String methodParam) { Assert.hasText(methodParam, "'methodParam' must not be empty"); this.methodParam = methodParam; } @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; } } }
- Rest使用客户端工具。如PostMan可直接发送put、delete等方式请求。
请求处理-【源码分析】-怎么改变默认的_method （了解）
@Configuration(proxyBeanMethods = false) @ConditionalOnWebApplication(type = Type.SERVLET) @ConditionalOnClass({ Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class }) @ConditionalOnMissingBean(WebMvcConfigurationSupport.class) @AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10) @AutoConfigureAfter({ DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class, ValidationAutoConfiguration.class }) public class WebMvcAutoConfiguration { ... @Bean @ConditionalOnMissingBean(HiddenHttpMethodFilter.class) @ConditionalOnProperty(prefix = "spring.mvc.hiddenmethod.filter", name = "enabled", matchIfMissing = false) public OrderedHiddenHttpMethodFilter hiddenHttpMethodFilter() { return new OrderedHiddenHttpMethodFilter(); } ... }
@ConditionalOnMissingBean(HiddenHttpMethodFilter.class)意味着在没有HiddenHttpMethodFilter时，才执行hiddenHttpMethodFilter()。因此，我们可以自定义filter，改变默认的\_method。例如：
@Configuration(proxyBeanMethods = false) public class WebConfig{ //自定义filter @Bean public HiddenHttpMethodFilter hiddenHttpMethodFilter(){ HiddenHttpMethodFilter methodFilter = new HiddenHttpMethodFilter(); methodFilter.setMethodParam("_m"); return methodFilter; } }
@ConditionalOnMissingBean(HiddenHttpMethodFilter.class)意味着在没有HiddenHttpMethodFilter时，才执行hiddenHttpMethodFilter()。因此，我们可以自定义filter，改变默认的\_method。例如：
@Configuration(proxyBeanMethods = false) public class WebConfig{ //自定义filter @Bean public HiddenHttpMethodFilter hiddenHttpMethodFilter(){ HiddenHttpMethodFilter methodFilter = new HiddenHttpMethodFilter(); methodFilter.setMethodParam("_m"); return methodFilter; } }
<form action="/user" method="post"> <input name="_m" type="hidden" value="DELETE"/> <input value="REST-DELETE 提交" type="submit"/> </form>
