java文件上传Demo

说到文件上传我们要做到：

1.引入两个包：commons-fileupload-1.2.1.jar和commons-io-1.3.2.jar

2.将form改为上传文件模式：enctype="multipart/form-data"

3.开始编写相关代码

这里会用到几个关键的类：磁盘文件工厂DiskFileItemFactory ；创建servlet文件上传类：ServletFileUpload

还有几个重要的方法：DiskFileItemFactory类用于将以临时文件形式保存在磁盘上的存放目录的方法setRepository；

ServletFileUpload类得到表单中所有的数据，得到form表单中所有的元素方法：parseRequest

下面看具体代码：

说明以这种方式上传文件是保存在服务器端的！

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. <br>

	 */

	public void destroy() {

		super.destroy(); // Just puts "destroy" string in log

		// Put your code here

	}

	/**

	 * The doGet method of the servlet. <br>

	 *

	 * 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. <br>

	 *

	 * 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<FileItem> 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. <br>

	 *

	 * @throws ServletException if an error occurs

	 */

	public void init() throws ServletException {

		// Put your code here

	}

}

index.jsp页面：

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

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

  <head>

    <title>文件测试界面</title>

	<meta http-equiv="pragma" content="no-cache">

	<meta http-equiv="cache-control" content="no-cache">

	<meta http-equiv="expires" content="0">

	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

	<meta http-equiv="description" content="This is my page">

  </head>

  <body>

  	<div align="center">

    <form action="UploadServlet" enctype="multipart/form-data" method="post">

    	名称：<input name="name" /> <br>

    	图片：<input name="img" type="file"/><br>

    	<input type="submit" value="提交" />   

    	<input type="reset" value="重置" />

    </form>

    </div>

  </body>

</html>

ok.jsp页面：

 <body>

   	<h1 align="center">上传文件成功!</h1>

  </body>

实现效果就不截图了，有需要自己那过去用！

巴特西

java文件上传Demo

最新文章

热门文章