在java项目中使用Demo如何实现一个文件上传功能

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileUtils;
 
 
public class UploadServlet extends HttpServlet {
 
  /**
   * Constructor of the object.
   */
  public UploadServlet() {
    super();
  }
 
  /**
   * Destruction of the servlet. 

   */
  public void destroy() {
    super.destroy(); // Just puts "destroy" string in log
    // Put your code here
  }
 
  /**
   * The doGet method of the servlet. 

   *
   * This method is called when a form has its tag value method equals to get.
   *
   * @param request the request send by the client to the server
   * @param response the response send by the server to the client
   * @throws ServletException if an error occurred
   * @throws IOException if an error occurred
   */
  public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
 
    this.doPost(request, response);
  }
 
  /**
   * The doPost method of the servlet. 

   *
   * This method is called when a form has its tag value method equals to post.
   *
   * @param request the request send by the client to the server
   * @param response the response send by the server to the client
   * @throws ServletException if an error occurred
   * @throws IOException if an error occurred
   */
  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
 
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    DiskFileItemFactory sf= new DiskFileItemFactory();//实例化磁盘被文件列表工厂
    String path = request.getRealPath("/upload");//得到上传文件的存放目录
    sf.setRepository(new File(path));//设置文件存放目录
    sf.setSizeThreshold(1024*1024);//设置文件上传小于1M放在内存中
    String rename = "";//文件新生成的文件名
    String fileName = "";//文件原名称
    String name = "";//普通field字段
    //从工厂得到servletupload文件上传类
    ServletFileUpload sfu = new ServletFileUpload(sf);
     
    try {
      List lst = sfu.parseRequest(request);//得到request中所有的元素
      for (FileItem fileItem : lst) {
        if(fileItem.isFormField()){
          if("name".equals(fileItem.getFieldName())){
            name = fileItem.getString("UTF-8");
          }
        }else{
          //获得文件名称
          fileName = fileItem.getName();
          fileName = fileName.substring(fileName.lastIndexOf("\\")+1);
          String houzhui = fileName.substring(fileName.lastIndexOf("."));
          rename = UUID.randomUUID()+houzhui;
          fileItem.write(new File(path, rename));
        }
      }
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
     
    System.out.println("普通字段"+name);
    System.out.println("文件名称"+fileName);
    System.out.println("修改后生成的文件名称"+rename);
    response.sendRedirect("ok.jsp");
    out.flush();
    out.close();
  }
 
  /**
   * Initialization of the servlet. 

   *
   * @throws ServletException if an error occurs
   */
  public void init() throws ServletException {
    // Put your code here
  }
 
}

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>


   
  
  
  
    
  
  
 
 
  

  

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上传文件成功!