小编Zla*_*roh的帖子

我正在将图像上传到服务器,当图像上传时,它应该向我显示上传图像的拇指.缩略图未保存在硬盘上我使用InputStream和OutputStream.对于上传我是ustig tomahawk.

我的index.jsp:

<h:form id="uploadForm" enctype="multipart/form-data">
  <t:inputFileUpload id="fileupload" 
    accept="image/*" 
    storage="file"
    value="#{fileUpload.uploadedFile}" 
    styleClass="fileUploadInput"
    required="true" 
    validator="epacient.FileUploadValidator"
    requiredMessage="Obvezna izbira datoteke." 
  />
  <br />
  <h:message for="fileupload" infoStyle="color: green;"
    errorStyle="color: red;" />
  <br />
  <h:commandButton value="Upload" id="fileUploadButton"
    action="#{fileUpload.upload}" />
  <h:message for="uploadForm" style="color: red;" />
  <h:graphicImage value="#{fileUpload.thumb}"
    rendered="#{fileUpload.uploaded}" />

</h:form>

fileUpload.upload调用函数 String preview()

private  String thumb ;
public String preview() throws IOException{
  HttpServletResponse response = (HttpServletResponse)FacesContext
    .getCurrentInstance().getExternalContext().getResponse();
  try {
    FacesContext context = FacesContext.getCurrentInstance();
    Map requestMap = context.getExternalContext().getApplicationMap();
    byte[] bytes = (byte[])(requestMap.get("fileupload_bytes")); 
    // returns byte[]
    byte[] testByte …

如果注册用户跳转到login.jsp我希望将其重定向到youAreLoggedIn.jsp.这可以用<navigation-rule>吗？我知道如何在PHP中执行此操作,但不在JSP中执行此操作.当用户访问时login.jsp,必须检查用户是否已登录,我知道如何检查.但是如何触发这个动作呢？我应该制作一个新的servlet还是什么？

谢谢!