cos-26上传

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。