JAVA SERVLET上传文件的样码

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;

/**
 * Servlet implementation class FileUploadServlet
 */
@WebServlet(name = "FileUploadServlet", urlPatterns = {"/upload"})
@MultipartConfig
public class FileUploadServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    
    protected void processRequest(HttpServletRequest request,
            HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        ServletContext servletContext = this.getServletContext();
        String realPath = servletContext.getRealPath("/upload");
        final Part filePart = request.getPart("file");
        final String fileName = getFileName(filePart);
        
        OutputStream out = null;
        InputStream filecontent = null;
        final PrintWriter writer = response.getWriter();
        
        try {
            System.out.println(realPath  + "@@@@@@@@@@@@@@@@@@@@@@@@@");
            System.out.println( File.separator +  "@@@@@@@@@@@@@@@@@@@@@@@@@");
            System.out.println( fileName + "@@@@@@@@@@@@@@@@@@@@@@@@@");
            out = new FileOutputStream(
                    new File(realPath + File.separator + fileName));
            filecontent = filePart.getInputStream();
            
            int read;
            final byte[] bytes = new byte[1024];
            
            while ((read=filecontent.read(bytes)) != -1) {
                out.write(bytes, 0, read);
            }
            writer.println("upload file " + fileName + " to path " + realPath);
        } catch (FileNotFoundException fne) {
            writer.println("no upload path or upload path is wrong.");
            writer.println("<br/> error: " + fne.getMessage());
        } finally {
            if (out !=null) {
                out.close();
            }
            if (filecontent != null){
                filecontent.close();
            }
            if (writer != null) {
                writer.close();
            }
        }
    }
       
    private String getFileName(final Part part) {
        // TODO Auto-generated method stub
        for (String content: part.getHeader("content-disposition").split(";")) {
            System.out.println(content + "####################");
            if (content.trim().startsWith("filename")) {
                String filename = content.substring(
                        content.lastIndexOf("\\") +  1).trim().replace("\"", "");
                System.out.println(filename + "####################");
                return "2.zip";
                        
            }
        }
        return null;
    }

    /**
     * @see HttpServlet#HttpServlet()
     */
    public FileUploadServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        processRequest(request, response);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        processRequest(request, response);
    }

}