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使用 Commons-fileupload 上传文件

2017-01-16 10:29 375 查看

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

[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
<title>
1fff7
;File
upload</title>
[align=left]</head>[/align]
[align=left]<body>[/align]
//必须是multipart的表单数据。
[align=left] <form name="myform" action="demo1.jsp" method="post"[/align]
[align=left] enctype="multipart/form-data">[/align]
Your
name: <br>
[align=left] <input type="text" name="name" size="15"><br>[/align]
[align=left] File:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] <br>[/align]
[align=left] <input type="submit" name="submit" value="Commit">[/align]
[align=left] </form>[/align]
[align=left]</body>[/align]
[align=left]</html>[/align]

demo1.jsp

<%@ page language="java" contentType="text/html;
charset=GB18030"
[align=left] pageEncoding="GB18030"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.servlet.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.disk.*"%>[/align]
[align=left]<%@ page import="java.util.*"%>[/align]
[align=left] [/align]
<!DOCTYPE HTML PUBLIC "-//W3C//DTD
HTML 4.01 Transitional//EN">
[align=left]<%[/align]
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();
[align=left] //检查当前项目是普通表单项目还是上传文件。[/align]
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。
[align=left] out.print("<br>");[/align]
[align=left] } else {//如果是上传文件，显示文件名。[/align]
out.print("the
upload file name is" + item.getName());
[align=left] out.print("<br>");[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] } else {[/align]
out.print("the
enctype must be multipart/form-data");
[align=left] }[/align]
[align=left]%>[/align]
[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
<title>File
upload</title>
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left]</body>[/align]
</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

[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
<title>File
upload</title>
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left] <form name="myform" action="demo2.jsp" method="post"[/align]
[align=left] enctype="multipart/form-data">[/align]
[align=left] File1:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] File2:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] <br>[/align]
[align=left] <input type="submit" name="submit" value="Commit">[/align]
[align=left] </form>[/align]
[align=left]</body>[/align]
</html>

demo2.jsp

<%@ page language="java" contentType="text/html;
charset=GB18030"
[align=left] pageEncoding="GB18030"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.servlet.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.disk.*"%>[/align]
[align=left]<%@ page import="java.util.*"%>[/align]
[align=left]<%@ page import="java.io.*"%>[/align]
[align=left] [/align]
<!DOCTYPE HTML PUBLIC "-//W3C//DTD
HTML 4.01 Transitional//EN">
<%String
uploadPath="D:\\temp";
boolean isMultipart
= ServletFileUpload.isMultipartContent(request);
[align=left] if(isMultipart==true){[/align]
[align=left] try{[/align]
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();
[align=left] while(itr.hasNext()){//依次处理每个文件[/align]
FileItem
item=(FileItem)itr.next();
String
fileName=item.getName();//获得文件名，包括路径
[align=left] if(fileName!=null){[/align]
File
fullFile=new File(item.getName());
File
savedFile=new File(uploadPath,fullFile.getName());
[align=left] item.write(savedFile);[/align]
[align=left] }[/align]
[align=left] }[/align]
out.print("upload
succeed");
[align=left] }[/align]
catch(Exception
e){
[align=left] e.printStackTrace();[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] else{[/align]
out.println("the
enctype must be multipart/form-data");
[align=left] }[/align]
[align=left]%>[/align]
[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
<title>File
upload</title>
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left]</body>[/align]
</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

[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
<title>File
upload</title>
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left] <form name="myform" action="demo3.jsp" method="post"[/align]
[align=left] enctype="multipart/form-data">[/align]
[align=left] File:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] <br>[/align]
[align=left] <input type="submit" name="submit" value="Commit">[/align]
[align=left] </form>[/align]
[align=left]</body>[/align]
[align=left]</html>[/align]

demo3.jsp

<%@ page language="java" contentType="text/html;
charset=GB18030"
[align=left] pageEncoding="GB18030"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.servlet.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.disk.*"%>[/align]
[align=left]<%@ page import="java.util.*"%>[/align]
[align=left]<%@ page import="java.io.*"%>[/align]
[align=left] [/align]
<!DOCTYPE HTML PUBLIC "-//W3C//DTD
HTML 4.01 Transitional//EN">
[align=left]<%[/align]
File
uploadPath = new File("D:\\temp");//上传文件目录
if (!uploadPath.exists())
{
[align=left] uploadPath.mkdirs();[/align]
[align=left] }[/align]
[align=left] // 临时文件目录[/align]
File
tempPathFile = new File("d:\\temp\\buffer\\");
if (!tempPathFile.exists())
{
[align=left] tempPathFile.mkdirs();[/align]
[align=left] }[/align]
[align=left] try {[/align]
//
Create a factory for disk-based file items
DiskFileItemFactory
factory = new DiskFileItemFactory();
[align=left] [/align]
//
Set factory constraints
[align=left] factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是4kb[/align]
[align=left] factory.setRepository(tempPathFile);//设置缓冲区目录[/align]
[align=left] [/align]
//
Create a new file upload handler
ServletFileUpload
upload = new ServletFileUpload(factory);
[align=left] [/align]
//
Set overall request size constraint
[align=left] upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是4MB[/align]
[align=left] [/align]
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
[align=left] .getName());[/align]
[align=left] fi.write(savedFile);[/align]
[align=left] }[/align]
[align=left] }[/align]
out.print("upload
succeed");
} catch (Exception
e) {
[align=left] e.printStackTrace();[/align]
[align=left] }[/align]
[align=left]%>[/align]
[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
<title>File
upload</title>
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left]</body>[/align]
</html>

示例4

利用Servlet来实现文件上传。

Upload.java

[align=left]package com.zj.sample;[/align]
[align=left] [/align]
[align=left]import java.io.File;[/align]
[align=left]import java.io.IOException;[/align]
[align=left]import java.util.Iterator;[/align]
[align=left]import java.util.List;[/align]
[align=left] [/align]
[align=left]import javax.servlet.ServletException;[/align]
[align=left]import javax.servlet.http.HttpServlet;[/align]
[align=left]import javax.servlet.http.HttpServletRequest;[/align]
[align=left]import javax.servlet.http.HttpServletResponse;[/align]
[align=left] [/align]
[align=left]import org.apache.commons.fileupload.FileItem;[/align]
[align=left]import org.apache.commons.fileupload.disk.DiskFileItemFactory;[/align]
[align=left]import org.apache.commons.fileupload.servlet.ServletFileUpload;[/align]
[align=left] [/align]
[align=left]@SuppressWarnings("serial")[/align]
public class Upload extends HttpServlet
{
[align=left] private String uploadPath = "D:\\temp"; // 上传文件的目录[/align]
[align=left] private String tempPath = "d:\\temp\\buffer\\"; // 临时文件目录[/align]
[align=left] File tempPathFile;[/align]
[align=left] [/align]
[align=left] @SuppressWarnings("unchecked")[/align]
public void doPost(HttpServletRequest
request, HttpServletResponse response)
throws IOException,
ServletException {
[align=left] try {[/align]
//
Create a factory for disk-based file items
DiskFileItemFactory
factory = new DiskFileItemFactory();
[align=left] [/align]
//
Set factory constraints
[align=left] factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是4kb[/align]
[align=left] factory.setRepository(tempPathFile);// 设置缓冲区目录[/align]
[align=left] [/align]
//
Create a new file upload handler
ServletFileUpload
upload = new ServletFileUpload(factory);
[align=left] [/align]
//
Set overall request size constraint
[align=left] upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是4MB[/align]
[align=left] [/align]
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());
[align=left] fi.write(savedFile);[/align]
[align=left] }[/align]
[align=left] }[/align]
System.out.print("upload
succeed");
} catch (Exception
e) {
[align=left] // 可以跳转出错页面[/align]
[align=left] e.printStackTrace();[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] [/align]
public void init() throws ServletException
{
File
uploadFile = new File(uploadPath);
if (!uploadFile.exists())
{
[align=left] uploadFile.mkdirs();[/align]
[align=left] }[/align]
File
tempPathFile = new File(tempPath);
if (!tempPathFile.exists())
{
[align=left] tempPathFile.mkdirs();[/align]
[align=left] }[/align]
[align=left] }[/align]
}

demo4.html

[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
<title>File
upload</title>
[align=left]</head>[/align]
[align=left]<body>[/align]
// action="fileupload"对应web.xml中<servlet-mapping>中<url-pattern>的设置.
[align=left] <form name="myform" action="fileupload" method="post"[/align]
[align=left] enctype="multipart/form-data">[/align]
[align=left] File:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] <br>[/align]
[align=left] <input type="submit" name="submit" value="Commit">[/align]
[align=left] </form>[/align]
[align=left]</body>[/align]
</html>

web.xml

[align=left]<servlet>[/align]
[align=left] <servlet-name>Upload</servlet-name>[/align]
[align=left] <servlet-class>com.zj.sample.Upload</servlet-class>[/align]
[align=left]</servlet>[/align]
[align=left] [/align]
[align=left]<servlet-mapping>[/align]
[align=left] <servlet-name>Upload</servlet-name>[/align]
[align=left] <url-pattern>/fileupload</url-pattern>[/align]
</servlet-mapping>

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