java上传文件

来源：互联网发布：linux man pdf 编辑：程序博客网时间：2024/05/16 05:07

FileUpload下载地址：

　　http://commons.apache.org/fileupload/

　　下载：commons-fileupload-1.2.2-bin.zip 得到：commons-fileupload-1.2.2.jar

　　http://commons.apache.org/io/

　　下载：commons-io-1.4-bin.zip 得到：commons-io-1.4.jar

思路:

1.上传的文件通过http协议指定格式传输到后台

method="post" action="upload.action" enctype="multipart/form-data"

2.后台获取文件数据 (可以限制上传文件大小upload.setSizeMax())

DiskFileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);
List<FileItem> items = upload.parseRequest(req);

3.在指定目录下创建相同名称的文件然后将数据内容写入

String path = request.getServletContetxt().getRealPath("upload").getPath()+"\"+

+item.getName().substring(item.getName().lastIndexOf("/")+1);

item.write(new File(path));

<!--将文件作为一种数据格式;--><!--注意:1.method="post"  2.enctype="multipart/form-data"--><html><form id="form" name="form" method="post" action="upload.action" enctype="multipart/form-data">  <table >  <tr>      <td >      <input  type="file" style="font-size:14px" name="filename" />      </td>  </tr>  <tr>      <td >      <input type="submit" style="font-size:14px" value="上传文件"  />      </td>  </tr>  </table>  </form></html>

import java.io.File;import java.io.IOException;import java.io.PrintWriter;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.FileUploadException;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;public class UploadServlet extends HttpServlet {@Overrideprotected void service(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {req.setCharacterEncoding("gbk");resp.setContentType("text/html;charset=gbk");PrintWriter out = resp.getWriter();    //磁盘文件工厂类;   DiskFileItemFactory factory = new DiskFileItemFactory();   //关联关系创建ServletFileUpload类;   ServletFileUpload upload = new ServletFileUpload(factory);    List<FileItem> items;try {  //将req中的数据放入表单域;items = upload.parseRequest(req);for(FileItem item : items){//判断是否是文件if(!item.isFormField()) {//文件名称;String filename = item.getName();//前缀路径;//某些浏览器会将文件的绝对路径全部提交;（ie）Y (chrome)N    filename = filename.substring(filename.lastIndexOf("\\")+1);//在WebRoot下创建一个uploads文件夹;//找到服务器上的路径upload文件夹;File file = new File(req.getServletContext().getRealPath("uploads")+File.separator+filename);//文件的二进制已经在item对象中,导入file文件;item.write(file);out.print("<html><center >上传成功,3秒后跳转!</center></html>");return ;  }}} catch (Exception e) {e.printStackTrace();}out.print("<html><center>上传失败!</center></html>");} }

web.xml

web.xml   <servlet>  <servlet-name>upload</servlet-name>   <servlet-class>cn.lh.web.UploadServlet</servlet-class>  </servlet>  <servlet-mapping>   <servlet-name>upload</servlet-name>    <url-pattern>/upload.action</url-pattern>  </servlet-mapping>

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