上传文件

 

import  java.io.File;
import  java.io.IOException;
import  java.io.PrintWriter;
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.apache.commons.fileupload.FileItem;
import  org.apache.commons.fileupload.FileUploadException;
import  org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException;
import  org.apache.commons.fileupload.disk.DiskFileItemFactory;
import  org.apache.commons.fileupload.servlet.ServletFileUpload;


public   class  FileUploadServlet  extends  HttpServlet {
    private   static   final   long  serialVersionUID = 1L;

    public  FileUploadServlet() {
        super ();
    }
    protected   void  doGet(HttpServletRequest request,
            HttpServletResponse response) throws  ServletException, IOException {
        this .doPost(request, response);
    }

    protected   void  doPost(HttpServletRequest request,
            HttpServletResponse response) throws  ServletException, IOException {

        final   long  MAX_SIZE =  300  *  1024  *  1024 ; // 设置上传文件最大值
        // 允许上传的文件格式的列表
        final  String[] allowedExt =  new  String[] { "jpg" ,  "jpeg" ,  "gif" ,  "txt" ,
                "doc" , "mp3" ,  "wma" ,  "m4a" , "rar" , "zip"  };
        response.setContentType("text/html" );
        // 设置字符编码为UTF-8, 统一编码，处理出现乱码问题
        response.setCharacterEncoding("UTF-8" );

        // 实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload
        DiskFileItemFactory dfif = new  DiskFileItemFactory();
        dfif.setSizeThreshold(4096 ); // 设置上传文件时用于临时存放文件的内存大小,这里是4K.多于的部分将临时存在硬盘
        dfif.setRepository(new  File(request.getRealPath( "/" )
                + "ImagesUploadTemp" )); // 设置存放临时文件的目录,web根目录下的ImagesUploadTemp目录

        // 用以上工厂实例化上传组件
        ServletFileUpload sfu = new  ServletFileUpload(dfif);
        // 设置最大上传大小
        sfu.setSizeMax(MAX_SIZE);

        PrintWriter out = response.getWriter();
        // 从request得到所有上传域的列表
        List fileList = null ;
        try  {
            fileList = sfu.parseRequest(request);
        } catch  (FileUploadException e) { // 处理文件尺寸过大异常
            if  (e  instanceof  SizeLimitExceededException) {
                out.println("文件尺寸超过规定大小:"  + MAX_SIZE +  "字节<p />" );
                out
                        .println("<a href=/"FileUpload.html/" target=/"_top/">返回</a>" );
                return ;
            }
            e.printStackTrace();
        }
        // 没有文件上传
        if  (fileList ==  null  || fileList.size() ==  0 ) {
            out.println("请选择上传文件<p />" );
            out.println("<a href=/"FileUpload.html/" target=/"_top/">返回</a>" );
            return ;
        }
        // 得到所有上传的文件
        Iterator fileItr = fileList.iterator();
        // 循环处理所有文件
        while  (fileItr.hasNext()) {
            FileItem fileItem = null ;
            String path = null ;
            long  size =  0 ;
            // 得到当前文件
            fileItem = (FileItem) fileItr.next();
            // 忽略简单form字段而不是上传域的文件域(<input type="text" />等)
            if  (fileItem ==  null  || fileItem.isFormField()) {
                continue ;
            }
            // 得到文件的完整路径
            path = fileItem.getName();
            // 得到文件的大小
            size = fileItem.getSize();
            if  ( "" .equals(path) || size ==  0 ) {
                out.println("请选择上传文件<p />" );
                out
                        .println("<a href=/"FileUpload.html/" target=/"_top/">返回</a>" );
                return ;
            }

            // 得到去除路径的文件名
            String t_name = path.substring(path.lastIndexOf("//" ) +  1 );
            // 得到文件的扩展名(无扩展名时将得到全名)
            String t_ext = t_name.substring(t_name.lastIndexOf("." ) +  1 );
            // 拒绝接受规定文件格式之外的文件类型
            int  allowFlag =  0 ;
            int  allowedExtCount = allowedExt.length;
            for  (; allowFlag < allowedExtCount; allowFlag++) {
                if  (allowedExt[allowFlag].equals(t_ext))
                    break ;
            }
            if  (allowFlag == allowedExtCount) {
                out.println("请上传以下类型的文件<p />" );
                for  (allowFlag =  0 ; allowFlag < allowedExtCount; allowFlag++)
                    out.println("*."  + allowedExt[allowFlag]
                            + "   " );
                out
                        .println("<p /><a href=/"FileUpload.html/" target=/"_top/">返回</a>" );
                return ;
            }

            long  now = System.currentTimeMillis();
            // 根据系统时间生成上传后保存的文件名
            String prefix = String.valueOf(now);
            // 保存的最终文件完整路径,保存在web根目录下的ImagesUploaded目录下
//          String u_name = request.getRealPath("/") + "ImagesUploaded/"
//                  + prefix + "." + t_ext;
            String filename = prefix + "."  + t_ext;
            try  {
                // 保存文件到C://upload目录下
                fileItem.write(new  File( "C://upload//" +filename));
                System.out.println(filename);
                out.println("文件上传成功. 已保存为: "  + prefix +  "."  + t_ext
                        + "   文件大小: "  + size +  "字节<p />" );
                out
                        .println("<a href=/"FileUpload.html/" target=/"_top/">继续上传</a>" );
            } catch  (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

 

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd" >
< html >
< head >
< meta   http-equiv = "Content-Type"   content = "text/html; charset=UTF-8" >
< title > 文件上传 </ title >
</ head >
< body >
< form   action = "FileUploadServlet"   method = "post"
    enctype = "multipart/form-data" >
    < input   type = "file"   size = "30"
    name = "file01"   />   < br   />
        < input   type = "file"   size = "30"
    name = "file02"   />   < br   />
< input   name = "up"   type = "submit"   value = "上传"   /> </ form >
</ body >
</ html >