Apache Commons fileUpload文件上传多个示例分享

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本文通过实例来介绍如何使用commons-fileupload.jar，Apache的commons-fileupload.jar可方便的实现文件的上传功能，具体内容如下
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>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：http://zhangjunhd.blog.51cto.com/113473/18331/

[Apache] Apache Commons fileUpload文件上传多个示例分享

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