1。需要两个夹包文件：

commons-fileupload-1.2.1.jar、

commons-io-1.4.jar


2。页面文件上传



<form action="upload" method="post" enctype="multipart/form-data">
          file:<input type="file" name="file" /><br/>
          username:<input type="text" name="username"/><br/>
          <input type="submit" value="submit"/>
      </form>
  </body>


3.servlet处理页面请求；



package org.yinhe.servlet;

import java.io.File;
import java.io.IOException;
import java.util.List;

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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

@SuppressWarnings("serial")
public class UpLoadServlet extends HttpServlet {


    @SuppressWarnings("unchecked")
    public void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        DiskFileItemFactory factory = new DiskFileItemFactory();
        ServletFileUpload upload = new ServletFileUpload(factory);
        try {
            FileItem item = null;
            List<FileItem> items = upload.parseRequest(request);
            for (int i = 0; i < items.size(); i++) {
                item = items.get(i);
                if(item.isFormField()){
                    //如果是普通的控件
                    String fileName = item.getFieldName();
                    String username = item.getString();
                    System.out.println(fileName + ":" + username);
                }else{
                    //如果是文件上传的控件，一般我们需要将
                    //其内容转化为一个文件，并保存到服务器上面。
                    //item.getName()返回的文件名:某些操作系统
                    //，返回的文件名包含了路径，有一些不包含。
                    String name = item.getName();
                    String name2 = name.substring(name.lastIndexOf("/")+1);
                    System.out.println("name:"+name2);
                    //获取保存文件的路径
                    //getRealPath:返回服务器的某个目录的绝对路径。
                    String path = this.getServletContext().getRealPath("upload");
                    System.out.println("path:" + path);
                    item.write(new File(path+"/" + name2));
                }
            }
        } catch (Exception e) {
            throw new ServletException(e.getMessage());
        }
        response.sendRedirect("sucess.jsp");
    }

}