簡介
REST 即 Representational State Transfer。（資源）表現(xiàn)層狀態(tài)轉(zhuǎn)化。是目前最流行的一種互聯(lián)網(wǎng)軟件架構(gòu)。它結(jié)構(gòu)清晰、符合標準、易于理解、擴展方便，所以正得到越來越多網(wǎng)站的采用，POST, DELETE, PUT, GET 分別對應(yīng) CRUD。Spring3.0 開始支持 REST 風格的請求，是通過 org.springframework.web.filter.HiddenHttpMethodFilter 把 POST 請求轉(zhuǎn)化為 PUT 和 DELETE 請求。本次實驗采用的是 Spring4.0 。
HiddenHttpMethodFilter 源碼
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public static final String DEFAULT_METHOD_PARAM = "_method";@Override protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException { String paramValue = request.getParameter(this.methodParam); if ("POST".equals(request.getMethod()) && StringUtils.hasLength(paramValue)) { String method = paramValue.toUpperCase(Locale.ENGLISH); HttpServletRequest wrapper = new HttpMethodRequestWrapper(request, method); filterChain.doFilter(wrapper, response); } else { filterChain.doFilter(request, response); }} |
從 HiddenHttpMethodFilter 的源碼可以看出，Spring 根據(jù)請求中的 _method 參數(shù)進行轉(zhuǎn)化，因此如果想發(fā)起 REST 風格的 DELETE 或者 PUT 請求，只需要在表單中帶上 _method 參數(shù)，并且把 _method 的值設(shè)置為 DELETE 或者 PUT（大寫） 即可。詳細例子如下：
在 web.xml 中配置 HiddenHttpMethodFilter
編寫 handler 代碼
編寫頁面
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<!-- 配置 org.springframework.web.filter.HiddenHttpMethodFilter ，可以把 POST 請求轉(zhuǎn)化為 PUT 或者 DELETE 請求 --> <filter> <filter-name>HiddenHttpMethodFilter</filter-name> <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class> </filter> <filter-mapping> <filter-name>HiddenHttpMethodFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> |
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package rex.springmvc.handlers;import org.apache.log4j.Logger;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RequestParam;@RequestMapping(value="/restTest")@Controller private static final Logger logger = Logger.getLogger(RestTestHandler.class); private static final String SUCCESS = "success"; @RequestMapping(value="/restGet/{id}", method=RequestMethod.GET) public String restGet(@RequestParam(value="id", required=false) Integer id){ logger.debug("restGet:" + id); return SUCCESS; } @RequestMapping(value="/restPut/{id}", method=RequestMethod.PUT) public String restPut(@RequestParam(value="id", required=false) Integer id){ logger.debug("restPut:" + id); return SUCCESS; } @RequestMapping(value="/restDelete/{id}", method=RequestMethod.DELETE) public String restDelete(@RequestParam(value="id", required=false) Integer id){ logger.debug("restDelete:" + id); return SUCCESS; } @RequestMapping(value="/restPost", method=RequestMethod.POST) public String restPost(){ logger.debug("restPost"); return SUCCESS; }} |
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<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Rest Test</title></head><body> <br> <br> <a href="restTest/restGet/1" rel="external nofollow" >Test Rest Get</a> <br> <br> <form action="restTest/restPut/1" method="post"> <input type="hidden" name="_method" value="PUT"> <input type="submit" value="submit"> </form> <br> <br> <form action="restTest/restDelete/1" method="post"> <input type="hidden" name="_method" value="DELETE"> <input type="submit" value="submit"> </form> <br> <br> <form action="restTest/restPost" method="post"> <input type="submit" value="submit"> </form></body></html> |
注：handler 中 @RequestParam 注解必須加上 required 參數(shù)，否則訪問頁面會出現(xiàn)400錯誤。
總結(jié)
以上就是本文關(guān)于springmvc Rest風格介紹及實現(xiàn)代碼示例的全部內(nèi)容，希望對大家有所幫助。如有不足之處，歡迎留言指出。
原文鏈接：https://www.cnblogs.com/rexfang/p/6583266.html
