spring 3.0 应用springmvc 构造RESTful URL 详细讲解

由于下一版本的rapid-framwork需要集成spring RESTful URL,所以研究了一下怎么搭建. 并碰到了一下问题。

springmvc 3.0 中增加 RESTful URL功能，构造出类似javaeye现在的URL。 rest介绍

比如如下URL

/blog/1  HTTP GET =>    得到id = 1的blog
/blog/1  HTTP DELETE => 删除 id = 1的blog
/blog/1  HTTP PUT  =>   更新id = 1的blog
/blog     HTTP POST =>   新增BLOG

以下详细解一下spring rest使用.

首先，我们带着如下三个问题查看本文。

1. 如何在java构造没有扩展名的RESTful url,如 /forms/1,而不是 /forms/1.do

2. 由于我们要构造没有扩展名的url本来是处理静态资源的容器映射的，现在被我们的spring占用了，冲突怎么解决?

3. 浏览器的form标签不支持提交delete,put请求，如何曲线解决?

springmvc rest 实现

springmvc的resturl是通过@RequestMapping 及@PathVariable annotation提供的,通过如@RequestMapping(value="/blog/{id}",method=RequestMethod.DELETE)即可处理/blog/1 的delete请求.

@RequestMapping(value="/blog/{id}",method=RequestMethod.DELETE)
public ModelAndView delete(@PathVariable Long id,HttpServletRequest request,HttpServletResponse response) {
blogManager.removeById(id);
return new ModelAndView(LIST_ACTION);
}

@RequestMapping @PathVariable如果URL中带参数，则配合使用，如

@RequestMapping(value="/blog/{blogId}/message/{msgId}",method=RequestMethod.DELETE)
public ModelAndView delete(@PathVariable("blogId") Long blogId,@PathVariable("msgId") Long msgId,HttpServletRequest request,HttpServletResponse response) {
}

spring rest配置指南

1. springmvc web.xml配置

<!-- 该servlet为tomcat,jetty等容器提供,将静态资源映射从/改为/static/目录，如原来访问 http://localhost/foo.css ,现在http://localhost/static/foo.css -->
<servlet-mapping>
<servlet-name>default</servlet-name>
<url-pattern>/static/*</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>

<!-- URL重写filter,用于将访问静态资源http://localhost/foo.css 转为http://localhost/static/foo.css -->
<filter>
<filter-name>UrlRewriteFilter</filter-name>
<filter-class>org.tuckey.web.filters.urlrewrite.UrlRewriteFilter</filter-class>
<init-param>
<param-name>confReloadCheckInterval</param-name>
<param-value>60</param-value>
</init-param>
<init-param>
<param-name>logLevel</param-name>
<param-value>DEBUG</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>UrlRewriteFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

<!-- 覆盖default servlet的/, springmvc servlet将处理原来处理静态资源的映射 -->
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>

<!-- 浏览器不支持put,delete等method,由该filter将/blog?_method=delete转换为标准的http delete方法 -->
<filter>
<filter-name>HiddenHttpMethodFilter</filter-name>
<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
</filter>

<filter-mapping>
<filter-name>HiddenHttpMethodFilter</filter-name>
<servlet-name>springmvc</servlet-name>
</filter-mapping>

2. webapp/WEB-INF/springmvc-servlet.xml配置,使用如下两个class激活@RequestMapping annotation

<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"/>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"/>

完整配置

<beans default-autowire="byName"   >

<!-- 自动搜索@Controller标注的类 -->
<context:component-scan base-package="com.**.controller"/>

<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"/>

<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"/>

<!-- Default ViewResolver -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
<property name="prefix" value="/pages"/>
<property name="suffix" value=".jsp"></property>
</bean>

<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource" p:basename="i18n/messages"/>

<!-- Mapping exception to the handler view -->
<bean id="exceptionResolver" class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<!-- to /commons/error.jsp -->
<property name="defaultErrorView" value="/commons/error"/>
<property name="exceptionMappings">
<props>
</props>
</property>
</bean>

</beans>

3. Controller编写

/**
* @RequestMapping("/userinfo") 具有层次关系，方法级的将在类一级@RequestMapping之一,
* 如下面示例, 访问方法级别的@RequestMapping("/new"),则URL为 /userinfo/new
*/
@Controller
@RequestMapping("/userinfo")
public class UserInfoController extends BaseSpringController{
//默认多列排序,example: username desc,createTime asc
protected static final String DEFAULT_SORT_COLUMNS = null;

private UserInfoManager userInfoManager;

private final String LIST_ACTION = "redirect:/userinfo";

/**
* 通过spring自动注入
**/
public void setUserInfoManager(UserInfoManager manager) {
this.userInfoManager = manager;
}

/** 列表 */
@RequestMapping
public ModelAndView index(HttpServletRequest request,HttpServletResponse response,UserInfo userInfo) {
PageRequest<Map> pageRequest = newPageRequest(request,DEFAULT_SORT_COLUMNS);
//pageRequest.getFilters(); //add custom filters

Page page = this.userInfoManager.findByPageRequest(pageRequest);
savePage(page,pageRequest,request);
return new ModelAndView("/userinfo/list","userInfo",userInfo);
}

/** 进入新增 */
@RequestMapping(value="/new")
public ModelAndView _new(HttpServletRequest request,HttpServletResponse response,UserInfo userInfo) throws Exception {
return new ModelAndView("/userinfo/new","userInfo",userInfo);
}

/** 显示 */
@RequestMapping(value="/{id}")
public ModelAndView show(@PathVariable Long id,HttpServletRequest request,HttpServletResponse response) throws Exception {
UserInfo userInfo = (UserInfo)userInfoManager.getById(id);
return new ModelAndView("/userinfo/show","userInfo",userInfo);
}

/** 编辑 */
@RequestMapping(value="/{id}/edit")
public ModelAndView edit(@PathVariable Long id,HttpServletRequest request,HttpServletResponse response) throws Exception {
UserInfo userInfo = (UserInfo)userInfoManager.getById(id);
return new ModelAndView("/userinfo/edit","userInfo",userInfo);
}

/** 保存新增 */
@RequestMapping(method=RequestMethod.POST)
public ModelAndView create(HttpServletRequest request,HttpServletResponse response,UserInfo userInfo) throws Exception {
userInfoManager.save(userInfo);
return new ModelAndView(LIST_ACTION);
}

/** 保存更新 */
@RequestMapping(value="/{id}",method=RequestMethod.PUT)
public ModelAndView update(@PathVariable Long id,HttpServletRequest request,HttpServletResponse response) throws Exception {
UserInfo userInfo = (UserInfo)userInfoManager.getById(id);
bind(request,userInfo);
userInfoManager.update(userInfo);
return new ModelAndView(LIST_ACTION);
}

/** 删除 */
@RequestMapping(value="/{id}",method=RequestMethod.DELETE)
public ModelAndView delete(@PathVariable Long id,HttpServletRequest request,HttpServletResponse response) {
userInfoManager.removeById(id);
return new ModelAndView(LIST_ACTION);
}

/** 批量删除 */
@RequestMapping(method=RequestMethod.DELETE)
public ModelAndView batchDelete(@RequestParam("items") Long[] items,HttpServletRequest request,HttpServletResponse response) {

for(int i = 0; i < items.length; i++) {

userInfoManager.removeById(items[i]);
}
return new ModelAndView(LIST_ACTION);
}

}

上面是rapid-framework 新版本生成器生成的代码,以后也将应用此规则,rest
url中增删改查等基本方法与Controller的方法映射规则

/userinfo 			=> index()
/userinfo/new		=> _new()
/userinfo/{id}		=> show()
/userinfo/{id}/edit 		=> edit()
/userinfo 	POST		=> create()
/userinfo/{id} 	PUT	=> update()
/userinfo/{id} 	DELETE	=> delete()
/userinfo 	DELETE		=> batchDelete()

注(不使用 /userinfo/add => add() 方法是由于add这个方法会被maxthon浏览器当做广告链接过滤掉,因为包含ad字符)

4.
jsp 编写

<form:form action="${ctx}/userinfo/${userInfo.userId}" method="put">
</form:form>

生成的html内容如下, 生成一个hidden的_method=put,并于web.xml中的HiddenHttpMethodFilter配合使用，在服务端将post请求改为put请求

<form id="userInfo" action="/springmvc_rest_demo/userinfo/2" method="post">
<input type="hidden" name="_method" value="put"/>
</form>

另外一种方法是你可以使用ajax发送put,delete请求.

5. 静态资源的URL重写

如上我们描述，现因为将default servlet映射至/static/的子目录，现我们访问静态资源将会带一个/static/前缀.

如 /foo.gif, 现在访问该文件将是 /static/foo.gif.

那如何避免这个前缀呢，那就是应用URL rewrite,现我们使用 http://tuckey.org/urlrewrite/, 重写规则如下

<urlrewrite>
<!-- 访问jsp及jspx将不rewrite url,其它.js,.css,.gif等将重写,如 /foo.gif => /static/foo.gif -->
<rule>
<condition operator="notequal" next="and" type="request-uri">.*.jsp</condition>
<condition operator="notequal" next="and" type="request-uri">.*.jspx</condition>
<from>^(/.*\..*)$</from>
<to>/static$1</to>
</rule>
</urlrewrite>

另笔者专门写了一个 RestUrlRewriteFilter来做同样的事件，以后会随着rapid-framework一起发布. 比这个更加轻量级.

并且该代码已经贡献给spring,不知会不会在下一版本发布