springmvc Rest风格介绍及实现代码示例
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2023-12-16 15:43:22
简介
rest 即 representational state transfer。（资源）表现层状态转化。是目前最流行的一种互联网软件架构。它结构清晰、符合标准...
简介
rest 即 representational state transfer。（资源）表现层状态转化。是目前最流行的一种互联网软件架构。它结构清晰、符合标准、易于理解、扩展方便，所以正得到越来越多网站的采用，post, delete, put, get 分别对应 crud。spring3.0 开始支持 rest 风格的请求，是通过 org.springframework.web.filter.hiddenhttpmethodfilter 把 post 请求转化为 put 和 delete 请求。本次实验采用的是 spring4.0 。
hiddenhttpmethodfilter 源码
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);
}
}
从 hiddenhttpmethodfilter 的源码可以看出，spring 根据请求中的 _method 参数进行转化，因此如果想发起 rest 风格的 delete 或者 put 请求，只需要在表单中带上 _method 参数，并且把 _method 的值设置为 delete 或者 put（大写） 即可。详细例子如下：
在 web.xml 中配置 hiddenhttpmethodfilter
编写 handler 代码
编写页面
<!-- 配置 org.springframework.web.filter.hiddenhttpmethodfilter ，可以把 post 请求转化为 put 或者 delete 请求 -->
<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>
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
public class resttesthandler {
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;
}
}
<%@ 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 注解必须加上 required 参数，否则访问页面会出现400错误。
总结
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