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commons-fileupload兑现文件上传(1)

分类: IT文章 • 2024-04-03 20:59:00
commons-fileupload实现文件上传(1)

Apache Commons fileUpload实现文件上传

 

原创作品，允许转载，转载时请务必以超链接形式标明文章 原始出处 、作者信息和本声明。否则将追究法律责任。http://zhangjunhd.blog.51cto.com/113473/18331
Apache 的 commons-fileupload.jar 可方便的实现文件的上传功能，本文通过实例来介绍如何使用 commons-fileupload.jar 。
@author:ZJ 07-2-22
Blog: [url]http://zhangjunhd.blog.51cto.com/[/url]
    将 Apache 的 commons-fileupload.jar 放在应用程序的 WEB-INF\lib 下 ， 即可使用。下面举例介绍如何使用它的文件上传功能。
所使用的 fileUpload 版本为 1.2 ，环境为 Eclipse3.3+MyEclipse6.0 。 FileUpload 是基于 Commons IO 的，所以在进入项目前先确定 Commons IO 的 jar 包（本文使用 commons-io-1.3.2.jar ）在 WEB-INF\lib 下。
此文作示例工程可在文章最后的附件中下载。
示例 1
最简单的例子，通过 ServletFileUpload 静态类来解析 Request ，工厂类 FileItemFactory 会对 mulipart 类的表单中的所有字段进行处理，不只是 file 字段。 getName （）得到文件名， getString （）得到表单数据内容， isFormField （）可判断是否为普通的表单项。
demo1.html
< html >
< head >
    < meta http-equiv = "Content-Type" content = "text/html; charset=GB18030" >
    < title > File upload </ title >
</ head >
< body >
       // 必须是 multipart 的表单数据。
    < form name = "myform" action = "demo1.jsp" method = "post"
       enctype = "multipart/form-data" >
       Your name: < br >
       < input type = "text" name = "name" size = "15" >< br >
       File: < br >
       < input type = "file" name = "myfile" >< br >
       < br >
       < input type = "submit" name = "submit" value = "Commit" >
    </ form >
</ body >
</ html >
 
demo1.jsp
<%@ page language = "java" contentType = "text/html; charset=GB18030"
    pageEncoding = "GB18030" %>
<%@ page import = "org.apache.commons.fileupload.*" %>
<%@ page import = "org.apache.commons.fileupload.servlet.*" %>
<%@ page import = "org.apache.commons.fileupload.disk.*" %>
<%@ page import = "java.util.*" %>
 
<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" >
<%
    boolean isMultipart = ServletFileUpload.isMultipartContent(request); // 检查输入请求是否为 multipart 表单数据。
    if (isMultipart == true ) {
       FileItemFactory factory = new DiskFileItemFactory(); // 为该请求创建一个 DiskFileItemFactory 对象 ， 通过它来解析请求。执行解析后，所有的表单项目都保存在一个 List 中。
       ServletFileUpload upload = new ServletFileUpload(factory);
       List<FileItem> items = upload.parseRequest(request);
       Iterator<FileItem> itr = items.iterator();
       while (itr.hasNext()) {
           FileItem item = (FileItem) itr.next();
           // 检查当前项目是普通表单项目还是上传文件。
           if (item.isFormField()) { // 如果是普通表单项目，显示表单内容。
       String fieldName = item.getFieldName();
       if (fieldName.equals( "name" )) // 对应 demo1.html 中 type="text" name="name"
           out.print( "the field name is" + item.getString()); // 显示表单内容。
       out.print( "<br>" );
           } else { // 如果是上传文件，显示文件名。
       out.print( "the upload file name is" + item.getName());
       out.print( "<br>" );
           }
       }
    } else {
       out.print( "the enctype must be multipart/form-data" );
    }
%>
< html >
< head >
    < meta http-equiv = "Content-Type" content = "text/html; charset=GB18030" >
    < title > File upload </ title >
</ head >
< body >
</ body >
</ html >
结果：
the field name isjeff
the upload file name isD:\C 语言考试样题 \ 作业题 .rar
示例 2
上传两个文件到指定的目录。
demo2.html
< html >
< head >
    < meta http-equiv = "Content-Type" content = "text/html; charset=GB18030" >
    < title > File upload </ title >
</ head >
< body >
    < form name = "myform" action = "demo2.jsp" method = "post"
       enctype = "multipart/form-data" >
       File1: < br >
       < input type = "file" name = "myfile" >< br >
       File2: < br >
       < input type = "file" name = "myfile" >< br >
       < br >
       < input type = "submit" name = "submit" value = "Commit" >
    </ form >
</ body >
</ html >
 
demo2.jsp
<%@ page language = "java" contentType = "text/html; charset=GB18030"
    pageEncoding = "GB18030" %>
<%@ page import = "org.apache.commons.fileupload.*" %>
<%@ page import = "org.apache.commons.fileupload.servlet.*" %>
<%@ page import = "org.apache.commons.fileupload.disk.*" %>
<%@ page import = "java.util.*" %>
<%@ page import = "java.io.*" %>
 
<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" >
<% String uploadPath= "D:\\temp" ;
  boolean isMultipart = ServletFileUpload.isMultipartContent(request);
  if (isMultipart== true ){
      try {
        FileItemFactory factory = new DiskFileItemFactory();
        ServletFileUpload upload = new ServletFileUpload(factory);
        List<FileItem> items = upload.parseRequest(request); // 得到所有的文件
       Iterator<FileItem> itr = items.iterator();
        while (itr.hasNext()){ // 依次处理每个文件
         FileItem item=(FileItem)itr.next();
         String fileName=item.getName(); // 获得文件名，包括路径
         if (fileName!= null ){
             File fullFile= new File(item.getName());
             File savedFile= new File(uploadPath,fullFile.getName());
             item.write(savedFile);
         }
        }
        out.print( "upload succeed" );
      }
      catch (Exception e){
         e.printStackTrace();
      }
  }
  else {
      out.println( "the enctype must be multipart/form-data" );
  }
%>
< html >
< head >
< meta http-equiv = "Content-Type" content = "text/html; charset=GB18030" >
< title > File upload </ title >
</ head >
< body >
</ body >
</ html >
结果：
upload succeed
此时，在 "D:\temp" 下可以看到你上传的两个文件。
示例 3
上传一个文件到指定的目录，并限定文件大小。
demo3.html
< html >
< head >
    < meta http-equiv = "Content-Type" content = "text/html; charset=GB18030" >
    < title > File upload </ title >
</ head >
< body >
    < form name = "myform" action = "demo3.jsp" method = "post"
       enctype = "multipart/form-data" >
       File: < br >
       < input type = "file" name = "myfile" >< br >
       < br >
       < input type = "submit" name = "submit" value = "Commit" >
    </ form >
</ body >
</ html >
 
demo3.jsp
<%@ page language = "java" contentType = "text/html; charset=GB18030"
    pageEncoding = "GB18030" %>
<%@ page import = "org.apache.commons.fileupload.*" %>
<%@ page import = "org.apache.commons.fileupload.servlet.*" %>
<%@ page import = "org.apache.commons.fileupload.disk.*" %>
<%@ page import = "java.util.*" %>
<%@ page import = "java.io.*" %>
 
<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" >
<%
    File uploadPath = new File( "D:\\temp" ); // 上传文件目录
    if (!uploadPath.exists()) {
       uploadPath.mkdirs();
    }
    // 临时文件目录
    File tempPathFile = new File( "d:\\temp\\buffer\\" );
    if (!tempPathFile.exists()) {
       tempPathFile.mkdirs();
    }
    try {
       // Create a factory for disk-based file items
       DiskFileItemFactory factory = new DiskFileItemFactory();
 
       // Set factory constraints
       factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是 4kb
       factory.setRepository(tempPathFile); // 设置缓冲区目录
 
       // Create a new file upload handler
       ServletFileUpload upload = new ServletFileUpload(factory);
 
       // Set overall request size constraint
       upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是 4MB
 
       List<FileItem> items = upload.parseRequest(request); // 得到所有的文件
       Iterator<FileItem> i = items.iterator();
       while (i.hasNext()) {
           FileItem fi = (FileItem) i.next();
           String fileName = fi.getName();
           if (fileName != null ) {
       File fullFile = new File(fi.getName());
       File savedFile = new File(uploadPath, fullFile
              .getName());
       fi.write(savedFile);
           }
       }
       out.print( "upload succeed" );
    } catch (Exception e) {
       e.printStackTrace();
    }
%>
< html >
< head >
< meta http-equiv = "Content-Type" content = "text/html; charset=GB18030" >
< title > File upload </ title >
</ head >
< body >
</ body >
</ html >
示例 4
利用 Servlet 来实现文件上传。
Upload.java
package com.zj.sample;
 
import java.io.File;
import java.io.IOException;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
 
@SuppressWarnings ( "serial" )
public class Upload extends HttpServlet {
    private String uploadPath = "D:\\temp" ; // 上传文件的目录
    private String tempPath = "d:\\temp\\buffer\\" ; // 临时文件目录
    File tempPathFile ;
 
    @SuppressWarnings ( "unchecked" )
    public void doPost(HttpServletRequest request, HttpServletResponse response)
           throws IOException, ServletException {
       try {
           // Create a factory for disk-based file items
           DiskFileItemFactory factory = new DiskFileItemFactory();
 
           // Set factory constraints
           factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是 4kb
           factory.setRepository( tempPathFile ); // 设置缓冲区目录
 
           // Create a new file upload handler
           ServletFileUpload upload = new ServletFileUpload(factory);
 
           // Set overall request size constraint
           upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是 4MB
 
           List<FileItem> items = upload.parseRequest(request); // 得到所有的文件
           Iterator<FileItem> i = items.iterator();
           while (i.hasNext()) {
              FileItem fi = (FileItem) i.next();
              String fileName = fi.getName();
              if (fileName != null ) {
                  File fullFile = new File(fi.getName());
                  File savedFile = new File( uploadPath , fullFile.getName());
                  fi.write(savedFile);
              }
           }
           System. out .print( "upload succeed" );
       } catch (Exception e) {
           // 可以跳转出错页面
           e.printStackTrace();
       }
    }
 
    public void init() throws ServletException {
       File uploadFile = new File( uploadPath );
       if (!uploadFile.exists()) {
           uploadFile.mkdirs();
       }
       File tempPathFile = new File( tempPath );
        if (!tempPathFile.exists()) {
           tempPathFile.mkdirs();
       }
    }
}
 
demo4.html
< html >
< head >
    < meta http-equiv = "Content-Type" content = "text/html; charset=GB18030" >
    < title > File upload </ title >
</ head >
< body >
// action="fileupload" 对应 web.xml 中 <servlet-mapping> 中 <url-pattern> 的设置 .
    < form name = "myform" action = "fileupload" method = "post"
       enctype = "multipart/form-data" >
       File: < br >
       < input type = "file" name = "myfile" >< br >
       < br >
       < input type = "submit" name = "submit" value = "Commit" >
    </ form >
</ body >
</ html >
 
web.xml
< servlet >
    < servlet-name > Upload </ servlet-name >
    < servlet-class > com.zj.sample.Upload </ servlet-class >
</ servlet >
 
< servlet-mapping >
    < servlet-name > Upload </ servlet-name >
    < url-pattern > /fileupload </ url-pattern >
</ servlet-mapping >

本文出自 “子 孑 ” 博客，请务必保留此出处http://zhangjunhd.blog.51cto.com/113473/18331

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