spring 3.0 应用springmvc 构造RESTful URL 详细讲解

springmvc 3.0 中增加 RESTful URL功能，构造出类似javaeye现在的URL。 rest介绍 , 这里还有struts2 rest构造的一篇文章: 使用 Struts 2 开发 RESTful 服务

简单例子如下,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);   
    }   
       
}  

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/(现在好像已经访问不了), 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
RestUrlRewriteFilter 下载：见附件
以上内容参考：http://badqiu.iteye.com/blog/473301