文件上传在 JSP 中不起作用

Question

我正在尝试使用 JSP 上传文件，但出现错误并且没有上传文件。

我用于上传的 Servlet 代码。

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.*;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.*;
import javax.servlet.http.*;
import org.apache.tomcat.util.http.fileupload.FileItem;
import org.apache.tomcat.util.http.fileupload.FileUploadException;
import org.apache.tomcat.util.http.fileupload.RequestContext;
import org.apache.tomcat.util.http.fileupload.disk.DiskFileItemFactory;
import org.apache.tomcat.util.http.fileupload.servlet.ServletFileUpload;
import org.apache.tomcat.util.http.fileupload.servlet.ServletRequestContext;

/**
 *
 * @author Hemal
 */
@MultipartConfig
public class UploadServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    private static final String DATA_DIRECTORY = "data";
    private static final int MAX_MEMORY_SIZE = 1024 * 1024 * 2;
    private static final int MAX_REQUEST_SIZE = 1024 * 1024;

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

        File file;
        int maxFileSize = 5000 * 1024;
        int maxMemSize = 5000 * 1024;
        ServletContext context = request.getServletContext();
        String filePath = context.getInitParameter("file-upload");
        PrintWriter out=response.getWriter();
        // Verify the content type
        String contentType = request.getContentType();
        if ((contentType.contains("multipart/form-data"))) {

            DiskFileItemFactory factory = new DiskFileItemFactory();
            // maximum size that will be stored in memory
            factory.setSizeThreshold(maxMemSize);
            // Location to save data that is larger than maxMemSize.
            factory.setRepository(new File("data"));

            // Create a new file upload handler
            ServletFileUpload upload = new ServletFileUpload(factory);
            // maximum file size to be uploaded.
            upload.setSizeMax(maxFileSize);
            try {
                // Parse the request to get file items.
                List fileItems = upload.parseRequest(request);//ERROR ON THIS LINE

                // Process the uploaded file items
                Iterator i = fileItems.iterator();


                while (i.hasNext()) {
                    FileItem fi = (FileItem) i.next();
                    if (!fi.isFormField()) {
                        // Get the uploaded file parameters
                        String fieldName = fi.getFieldName();
                        String fileName = fi.getName();
                        boolean isInMemory = fi.isInMemory();
                        long sizeInBytes = fi.getSize();
                        // Write the file
                        if (fileName.lastIndexOf("\\") >= 0) {
                            file = new File(filePath
                                    + fileName.substring(fileName.lastIndexOf("\\")));
                        } else {
                            file = new File(filePath
                                    + fileName.substring(fileName.lastIndexOf("\\") + 1));
                        }
                        fi.write(file);
                        out.println("Uploaded Filename: " + filePath
                                + fileName + "<br>");
                    }
                }

                } catch (Exception ex) {
                System.out.println(ex);
            }
        }
    }
}

我在线收到错误

`List fileItems = upload.parseRequest(request);`

是 HttpServletRequest cannot be converted to RequestContext

我尝试了很多选择，但都没有成功。

谢谢。

编辑

jsp中文件上传的其他链接只显示部分代码，没有将实际文件保存到用户定义的目录。我想要一个将文件也保存到目录的代码。所以我认为这不是一个重复的问题。

Answer 1

你可以用这个：

InputStream content = uploadedFile.getInputStream();
byte[] fileArray = new byte[chooseTheSize];  //Here you must use a size big enough.
content.read(fileArray);

//fileArray 是你的文件。