如何让struts2和servlet的共存

Posted 2020-06-14

如何让struts2和servlet的共存

 (2013-08-29 14:07:49)

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标签：  servlet与struts2共存   同时配置struts2与ser   servlet访问不到

分类： Struts2

  一、问题的提出
   先让我们看下web.xml中struts2和servlet的配置：
    <!-- struts2拦截页面请求的配置 -->
   <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

     <!-- servlet的配置 -->
    <servlet>
        <servlet-name>ImageServlet</servlet-name>
        <servlet-class>com.servlets.ImageServlet
        </servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ImageServlet</servlet-name>
        <url-pattern>/myImageServlet/*</url-pattern>
    </servlet-mapping>
  当我们在页面在请求应用时，struts2将会截获所有请求，对于servlet请求将不能够正常响应的
（报错信息为：HTTP Status 404 - There is no Action mapped for namespace / and action name myImageServlet.）,
这是因为struts2把servlet当成action了，因为servlet和action都是没有后缀的.

二、解决方案
   解决方法目前有四种：
方法1：
   统一在servlet后面加上.servlet结尾（包括web.xml配置文件中和页面上使用servlet的地方）

方法2（比较通用奥）：
    在struts.xml中的<struts>的节点下面添加struts2处理的请求后缀 常量：
<!--  
该属性指定需要Struts 2处理的请求后缀，该属性的默认值是action，即所有匹配*.action的请求都由Struts 2处理。 
如果用户需要指定多个请求后缀，则多个后缀之间以英文逗号（，）隔开。 
 --> 
<constant name="struts.action.extension" value="action" /> 

方法3：
     在web.xml中修改struts2拦截页面请求的配置：
原：
   <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

现：

   <filter-mapping>
      <filter-name>struts2</filter-name>
      <url-pattern>*.action</url-pattern>
   </filter-mapping>
   <filter-mapping>
      <filter-name>struts2</filter-name>
      <url-pattern>*.jsp</url-pattern>
   </filter-mapping>
   <filter-mapping>
      <filter-name>struts2</filter-name>
      <url-pattern>/user/*</url-pattern>
   </filter-mapping>
  servlet的请求路径不必改变

方法4：
     自定义filter对servlet进行过滤：
##############################################
# 该类是定义了一个过滤器（随便你放在摸个包下面），当既用到struts2有用到servlet时，
# 必须用该过滤器对所有的servlet做一次过滤，否则servlet将无法正常运行。
# 同时在web.xml中，在定义struts的核心控制器的过滤器前面添加该过滤器，添加代码如下：
* <filter>
*   <filter-name>redisp</filter-name>
*   <filter-class>filters.ReDispatcherFilter（该过滤器的类名）</filter-class>
*   <init-param>
*    <param-name>includeServlets</param-name>
*    <param-value>所配置的servlet，注意是那url-pattern</param-value>
*   </init-param>
* </filter>
* <filter-mapping>
*   <filter-name>redisp</filter-name>
*   <url-pattern>/*</url-pattern>
* </filter-mapping>
*该类也可以直接继承StrutsPrepareAndExecuteFilter的
###########################################################
public class ReDispatcherFilter implements Filter {

public void destroy() {
   // TODO Auto-generated method stub
}

public void doFilter(ServletRequest req, ServletResponse resp,
    FilterChain chain) throws IOException, ServletException
{
 
   HttpServletRequest request = (HttpServletRequest)req;
   String target = request.getRequestURI();
   target = target.lastIndexOf("?")>0  
 ?target.substring(target.lastIndexOf("/")+1,target.lastIndexOf("?")-target.lastIndexOf("/"))
      :target.substring(target.lastIndexOf("/")+1);
   System.out.println(target);
   if(this.includes.contains(target))
   {
    RequestDispatcher rdsp = request.getRequestDispatcher(target);  
    System.out.println("go..............."+rdsp);
    rdsp.forward(req, resp);
   }
   else
    chain.doFilter(req, resp);
}
private ArrayList<String> includes = new ArrayList<String>();

public void init(FilterConfig config) throws ServletException {
   this.includes.addAll( Arrays.asList(config.getInitParameter("includeServlets").split(",")));
}

}
怕大家还是配置错误，给一个web.xml的配置实例。

  <filter>
        <filter-name>redisp</filter-name>
        <filter-class>
com.xheditor.servlet.ReDispatcherFilter</filter-class>
        <init-param>
            <param-name>includeServlets</param-name>
            <param-value>UploadFileServlet</param-value>
           </init-param>
     </filter>
    <filter-mapping>
        <filter-name>redisp</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
     
<!-- struts2拦截页面请求的配置 -->
   <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <!-- servlet的配置 -->
    <servlet>
        <servlet-name>ImageServlet</servlet-name>
        <servlet-class>com.servlets.ImageServlet
        </servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ImageServlet</servlet-name>
        <url-pattern>/myImageServlet/*</url-pattern>
    </servlet-mapping>