使用cos实现多个文件下传详解

使用cos实现多个文件上传详解

在开发中常常需要上传文件，上传文件的方式有很多种，这里有一个cos实现的例子。

首先是要拷贝cos.jar包拷贝到WEB-INF/lib目录下，然后才进行编码。

创建一个可以进行自动重命名的Java文件FileRenameUtil.java：

package org.ml.drp.util;

import java.io.File;
import java.util.Date;

import com.oreilly.servlet.multipart.FileRenamePolicy;

/**
 * 文件重命名
 * @author MuLing
 *
 */
public class FileRenameUtil implements FileRenamePolicy {

	public File rename(File file) {
		String body = "";
		String ext = "";
		Date date = new Date();
		int pot = file.getName().lastIndexOf(".");//取得文件名和后缀分割点
		if (pot != -1) {//说明后缀存在
			body = date.getTime() + "";//采用时间的形式命名
			ext = file.getName().substring(pot);//截取后缀名
		} else {
			body = (new Date()).getTime() + "";
			ext = "";
		}
		String newName = body + ext;
		file = new File(file.getParent(), newName);//对文件进行重命名
		return file;

	}

}

然后创建一个实现上传功能的servlet，为了方便查看上传情况，所以加入了一些输出语句。

FileUploadServlet.java

package org.ml.servlet;

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

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.oreilly.servlet.MultipartRequest;

/**
 * 能够进行文件上传的servlet类
 * @author MuLing
 *
 */
public class UploadServlet extends HttpServlet { 
	private static final long serialVersionUID = 1L;

	public UploadServlet() {
		super();
	}
 
	public void destroy() {
		super.destroy();  
	}
 
	@SuppressWarnings("unchecked")
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 存绝对路径
		// String filePath = "C://upload";
		// 存相对路径
		String filePath = getServletContext().getRealPath("/") + "upload";
		System.out.println(filePath);//输出存放上传文件所到的路径
		File uploadPath = new File(filePath);
		// 检查文件夹是否存在 不存在 创建一个
		if (!uploadPath.exists()) {
			uploadPath.mkdir();
		}
		// 文件最大容量 3M
		int fileMaxSize = 3 * 1024 * 1024;
		// 存放文件描述
		@SuppressWarnings("unused")
		String[] fileDiscription = { null, null };
		// 文件名
		String fileName = null;
		// 上传文件数
		int fileCount = 0;
		// 重命名策略
		RandomFileRenamePolicy rfrp = new RandomFileRenamePolicy();
		// 上传文件
		MultipartRequest mulit = new MultipartRequest(request, filePath,
				fileMaxSize, "UTF-8", rfrp);//取得上传文件

		String userName = mulit.getParameter("userName");
		System.out.println(userName);

		Enumeration filesname = mulit.getFileNames();//取得上传的所有文件(相当于标识) 
		while (filesname.hasMoreElements()) {
			String name = (String) filesname.nextElement();//标识
			System.out.println(name);
			fileName = mulit.getFilesystemName(name); //取得文件名
			String contentType = mulit.getContentType(name);//工具标识取得的文件类型
			if (fileName != null) {
				fileCount++;
			}
			System.out.println("文件名：" + fileName);
			System.out.println("文件类型： " + contentType); 
		}
		System.out.println("共上传" + fileCount + "个文件！"); 
	}
 
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException { 
		this.doGet(request, response);
	} 
	
	public void init() throws ServletException {
	}

}

在web.xml文件中的配置servlet如下:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <servlet> 
    <servlet-name>UploadServlet</servlet-name>
    <servlet-class>org.ml.servlet.UploadServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>UploadServlet</servlet-name>
    <url-pattern>/UploadServlet</url-pattern>
  </servlet-mapping>
  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

上传页面代码如下：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head> 
  </head>
  
  <body>
  	<form enctype="multipart/form-data" method = "post" action = "UploadServlet">
	    <input type="text" name="userName" /> 
	   <p>上传文件1:<input type = "file" name = "File1" size = "20" maxlength = "20"><br></p>
	   <p>上传文件2:<input type = "file" name = "File2" size = "20" maxlength = "20"><br></p>
	   <p>上传文件3:<input type = "file" name = "File3" size = "20" maxlength = "20"><br></p>
	   <p>上传文件4:<input type = "file" name = "File4" size = "20" maxlength = "20"><br></p>
	   <input type = "submit" value = "上传">
	</form>
  </body>
</html>

上面完成同时上传一个或者多个文件的操作，使用起来很方便。

使用cos实现多个文件下传详解

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