怎么实现文件上传

import
import
import
import java.util.Iterator;
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.
import org.
import org.
import org.
import org.

public class UploadServlet extends HttpServlet {
    public UploadServlet() {
        super();
    }
    public void destroy() {
        super.destroy();     
    }
    public void execute(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
   //初始化servletfileupload对象，该对象提供了从表单中得到二进制数据的方法
        ServletFileUpload file=new ServletFileUpload(new DiskFileItemFactory());
        //包含多个文件
        try {
            List<FileItem>list=file.parseRequest(request);
            //得到上传文件的请求
            Iterator<FileItem> i=list.iterator();
            //因为有多个文件所以把这些文件放到LIST集合中
            while(i.hasNext()){
                FileItem fileitem=(FileItem)i.next();
            //对这个集合进行迭代
                String filename=fileitem.getName();
                System.out.println("文件的名字是"+filename);
            if(fileitem.isFormField()){
                //因为传过来的数据有的是表单数据，不是文件
                //所以要判断
            //isFormField()是判断文件是表单数据
                String filename2=fileitem.getName();
                String filevalue=fileitem.getString("GBK");
                System.out.println(filename2+filevalue);
                request.setAttribute("name",filevalue);
            }
            else{
                //如果传来的是文件的话
                String path=fileitem.getName();
                System.out.println(path);
                int count=path.lastIndexOf("\\");
                //首先截取这个文件名
                String name=path.substring(count+1);
                //因为indexof是从0开始，所以要+1
                try {
                    fileitem.write(new File("e:\\上传的文件"+name));
                //将文件写到你要的路径即可
                } catch (Exception e) {
                    e.printStackTrace();
                }
             }
            }
            
        } catch (FileUploadException e) {
            e.printStackTrace();
        }  
    }
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
  execute(request, response);
    }   
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
          execute(request, response);
    }
    public void init() throws ServletException {   
    }
}
希望帮到你。

这个是我以前写得：
jsp文件上传、下载 ：http://blog.
使用jspSmartUpload组件进行文件上传、下载 ：http://blog.