servlet不能在GWT中工作 [英] servlet not working in GWT

问题描述

我试图在GWT中使用servlet。并找到
错误。

 找不到找到的文件：/ uploadfile / uploadFileServlet 
  
 
我想浏览一个文件并在服务器端发送它。
 
 
 
我经历了许多专家提供的解决方案。但我无法找到我的错误
 
 
 
有一个plz帮助解决它。
 
 
 
客户端
  package uploadfile.client; 
 public class Uploadfile实现EntryPoint {
 
 @SuppressWarnings（deprecation）
 public void onModuleLoad（）{
 // TODO自动生成的方法存根
 final FormPanel uploadForm = new FormPanel（）; 
 
 uploadForm.setAction（GWT.getModuleBaseURL（）+uploadFileServlet）; 
 
 uploadForm.setEncoding（FormPanel.ENCODING_MULTIPART）; 
 uploadForm.setMethod（FormPanel.METHOD_POST）; 
 
 //创建一个面板来容纳所有的表单小部件。 
 VerticalPanel面板=新的VerticalPanel（）; 
 uploadForm.setWidget（panel）; 
 
 //创建一个FileUpload小部件。 
 FileUpload upload = new FileUpload（）; 
 upload.setName（uploadFormElement）; 
 panel.add（上传）; 
 
 //添加一个'提交'按钮。 
 Button uploadSubmitButton =新建按钮（提交）; 
 panel.add（uploadSubmitButton）; 
 uploadSubmitButton.addClickListener（new ClickListener（）{
 public void onClick（Widget sender）{$ b $ uploadForm.submit（）; 
} 
}）; 
 uploadForm.addFormHandler（new FormHandler（）{
 public void onSubmit（FormSubmitEvent event）{
} 
 public void onSubmitComplete（FormSubmitCompleteEvent event）{
 Window.alert event.getResults（））; 
} 
}）; 
 RootPanel.get（）。add（uploadForm）; 
} 
 
} 
  
服务器端
  package uploadfile.server; 
 
 
 public class UploadFileServlet extends HttpServlet implements Servlet 
 {
 private static final long serialVersionUID = 8305367618713715640L; 
 $ b保护无效doGet（HttpServletRequest请求，
 HttpServletResponse响应）
抛出ServletException，IOException {
 doPost（request，response）; 
 
 $ b保护无效doPost（HttpServletRequest请求，
 HttpServletResponse响应）
抛出ServletException，IOException {
 
 response.setContentType（text /纯）; 
 FileItem uploadItem = getFileItem（request）; 
 if（uploadItem == null）{
 response.getWriter（）。write（NO-SCRIPT-DATA）; 
 return; 
} 
 byte [] fileContents = uploadItem.get（）; 
 // TODO：在这里添加代码来处理文件内容。我们将只打印
 
 System.out.println（new String（fileContents））; 
 response.getWriter（）。write（new String（fileContents））; 
 
 
私有FileItem getFileItem（HttpServletRequest请求）{
 
 FileItemFactory factory = new DiskFileItemFactory（）; 
 ServletFileUpload upload = new ServletFileUpload（factory）; 
尝试{
 List items = upload.parseRequest（request）; 
 Iterator it = items.iterator（）; （it.hasNext（））{
 FileItem item =（FileItem）it.next（）; 
 if（！item.isFormField（）
&&uploadFormElement.equals（item.getFieldName（）））{
 return item; 
} 
} 
} catch（FileUploadException e）{
 return null; 
} 
返回null; 
} 
} 
  
 web.xml 
 <？xml version =1.0encoding =UTF-8？> 
< web-app version =2.5xmlns =http://java.sun.com/xml/ns/javaee
 xmlns：xsi =http：//www.w3。 org / 2001 / XMLSchema-instancexsi：schemaLocation =http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd > 
< servlet> 
< servlet-name> fileUploaderServlet< / servlet-name> 
< servlet-class> uploadfile.server.UploadFileServlet< / servlet-class> 
< / servlet> 
<！ -  Servlets 
要服务的默认页面 - > 
 
< servlet-mapping> 
< servlet-name> fileUploaderServlet< / servlet-name> 
< url-pattern> / uploadFileServlet< / url-pattern> 
< / servlet-mapping> 
< welcome-file-list> 
< welcome-file> Uploadfile.html< / welcome-file> 
< / welcome-file-list> 
< / web-app> 
  
 
 
解决方案
我不是GWT开发者，所以它可能会有所不同，我认为你的servlet动作url是错误的。您正在尝试使用路径 / uploadfile / uploadFileServlet 的servlet，但是您的servlet实际上已映射到url  / uploadFileServlet 。  
 
 
另外，如果你扩展 Servlet  > HttpServlet ，除非你有任何具体的理由。
 
I am trying to work with servlet in GWT. and i found 
 Error.
   No file found for: /uploadfile/uploadFileServlet
i want to browse a file and send it on the server side.

i went through many solution provided by the experts. But i am not able to find my mistake

some one plz help to solve it.

Client Side
package uploadfile.client;
public class Uploadfile implements EntryPoint {

    @SuppressWarnings("deprecation")
    public void onModuleLoad() {
        // TODO Auto-generated method stub
            final FormPanel uploadForm = new FormPanel(); 

            uploadForm.setAction(GWT.getModuleBaseURL() +"uploadFileServlet"); 

            uploadForm.setEncoding(FormPanel.ENCODING_MULTIPART); 
            uploadForm.setMethod(FormPanel.METHOD_POST); 

            // Create a panel to hold all of the form widgets. 
            VerticalPanel panel = new VerticalPanel(); 
            uploadForm.setWidget(panel); 

            // Create a FileUpload widget. 
            FileUpload upload = new FileUpload(); 
            upload.setName("uploadFormElement"); 
            panel.add(upload); 

            // Add a 'submit' button. 
            Button uploadSubmitButton = new Button("Submit"); 
            panel.add(uploadSubmitButton); 
            uploadSubmitButton.addClickListener(new ClickListener() { 
              public void onClick(Widget sender) { 
                uploadForm.submit(); 
              } 
            }); 
            uploadForm.addFormHandler(new FormHandler() { 
              public void onSubmit(FormSubmitEvent event) { 
              } 
              public void onSubmitComplete(FormSubmitCompleteEvent event) { 
                Window.alert(event.getResults()); 
              } 
            }); 
            RootPanel.get().add(uploadForm); 
    }

}
Server side
package uploadfile.server;


public class UploadFileServlet extends HttpServlet implements Servlet 
{ 
   private static final long serialVersionUID = 8305367618713715640L; 

    protected void doGet(HttpServletRequest request, 
        HttpServletResponse response) 
                        throws ServletException, IOException { 
  doPost(request, response);
 }

 protected void doPost(HttpServletRequest request, 
        HttpServletResponse response) 
                        throws ServletException, IOException { 

    response.setContentType("text/plain"); 
    FileItem uploadItem = getFileItem(request); 
    if (uploadItem == null) { 
            response.getWriter().write("NO-SCRIPT-DATA"); 
            return; 
    } 
    byte[] fileContents = uploadItem.get(); 
    //TODO: add code to process file contents here. We will just print 

    System.out.println(new String(fileContents)); 
    response.getWriter().write(new String(fileContents)); 
  } 

   private FileItem getFileItem(HttpServletRequest request) { 

  FileItemFactory factory = new DiskFileItemFactory(); 
  ServletFileUpload upload = new ServletFileUpload(factory); 
  try { 
      List items = upload.parseRequest(request); 
      Iterator it = items.iterator(); 
      while (it.hasNext()) { 
          FileItem item = (FileItem) it.next(); 
          if (!item.isFormField() 
                  && "uploadFormElement".equals(item.getFieldName())) { 
              return item; 
          } 
      } 
  } catch (FileUploadException e) { 
      return null; 
  } 
 return null; 
  } 
 } 
web.xml
  <?xml version="1.0" encoding="UTF-8"?>
 <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee                  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>fileUploaderServlet</servlet-name>
<servlet-class>uploadfile.server.UploadFileServlet</servlet-class>
</servlet>
<!-- Servlets 
Default page to serve -->

<servlet-mapping>
<servlet-name>fileUploaderServlet</servlet-name>
<url-pattern>/uploadFileServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>Uploadfile.html</welcome-file>
 </welcome-file-list>
</web-app>

解决方案
Am not a GWT developer so it could be different, i think your servlet action url is wrong. You are trying for a servlet with path /uploadfile/uploadFileServlet but your servlet is actually mapped to the url /uploadFileServlet.

One more thing, there is no need for you to implement Servlet if you are extending HttpServlet unless you have any specific reasons to do.

                        
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