[英]Why I can't get access to parameters from a request after upload a file in jsp?
我正在使用jsp和servlet來做到這一點。
我有一個聯系表,可以發送包含一些數據(名稱,主題,問題,聯系電子郵件等)和文件的電子郵件。
當我提交表單並獲得servlet響應時,僅返回第一件事。
String file= fileUpload(request); //upload the client's file and return the absolute path of the file in the server
//testing the rest of parameters
out.println("REQUEST LIST"
"\n" request.getParameter("name")
"\n" request.getParameter("mail")
"\n" request.getParameter("subject")
"\n" request.getParameter("ask")
"\n");
按此順序成功上傳了文件,但其他參數(名稱,郵件等)為空。
按以下順序,參數正常,它們正確返回數據。 但該文件未上傳。
//testing the rest of parameters
out.println("REQUEST LIST"
"\n" request.getParameter("name")
"\n" request.getParameter("mail")
"\n" request.getParameter("subject")
"\n" request.getParameter("ask")
"\n");
String file= fileUpload(request); //upload the client's file and return the absolute path of the file in the server
我怎么都可以? 謝謝!
您應該使用與提取上傳文件相同的 API(例如Apache Commons FileUpload)提取請求參數。 這通常無法與調用getParameter()
互換使用,因為請求正文只能被解析一次(最終用戶不會發送相同的請求兩次,一個要由文件上傳解析API解析,另一個要由getParameter()
解析) getParameter()
)。
查看以下代碼是否對您有幫助。 這只是一個例子。 您可能需要調整它
創建一個名為FileUploader
的類,該類返回ServletFileUpload
對象
public class FileUploader
{
private static ServletFileUpload uploader;
private FileUploader()
{
}
public static synchronized ServletFileUpload getservletFileUploader(String tempDir, int maxSizeInMB)
{
if(uploader == null)
{
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(1024 * 1024);
factory.setRepository(new File(tempDir));
uploader = new ServletFileUpload(factory);
uploader.setFileSizeMax(maxSizeInMB * 1024 * 1024);
}
return uploader;
}
}
現在您可以處理請求並讀取所有數據
protected MultiPartFormData handleMultiPartRequest(HttpServletRequest request)
throws FileSizeLimitExceededException
{
if(!isMultipartRequest(request))
return null;
ServletFileUpload upload = FileUploader.getservletFileUploader(tempDir, 50);
MultiPartFormData data = new MultiPartFormData();
try
{
List<FileItem> items = upload.parseRequest(request);
for (FileItem item : items)
{
if(item.isFormField())
{
data.getParameters().put(item.getFieldName(), item.getString());
}
else
{
String filename = item.getName();
//Internet explorer and firefox will send the file name differently
//Internet explorer will send the entire path to the file name including
//the backslash characters etc ... we should strip it down
//THIS IS HACKY
if(filename.indexOf("\\") != -1)
{
int index = filename.lastIndexOf("\\");
filename = filename.substring(index + 1);
}
if(filename == null || filename.equals(""))
{
//do nothing
}
else
{
File uploadFile = new File(uploadDir + File.separator + randomFileName);
item.write(uploadFile);
data.addFile(item.getFieldname(), item.getString());
}
}
}
}
catch(FileSizeLimitExceededException e)
{
throw e;
}
catch(Exception e)
{
e.printStackTrace();
}
return data;
}
解析請求后,我將其存儲在一個稱為MultipartFormData的對象中,該對象可用於獲取請求參數
public class MultiPartFormData {
private Hashtable<String, String> parameters;
private Hashtable<String, String> uploadedFiles;
public MultiPartFormData()
{
this.parameters = new Hashtable<String, String>();
this.uploadedFiles = new Hashtable<String, String>();
}
public Hashtable<String, String> getParameters() {
return parameters;
}
public void setParameters(Hashtable<String, String> parameters) {
this.parameters = parameters;
}
public void getParameter(String paramName) {
if(this.parameters.contains(paramName))
return tyhis.parameters.get(paramName);
return null;
}
public void addFile(String key, String filename) {
uploadedFile.put(key, filename);
}
public void getFilename(String key) {
uploadedFile.get(key);
}
}
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