本文通過實例來介紹如何使用commons-fileupload.jar，Apache的commons-fileupload.jar可方便的實現文件的上傳功能，具體內容如下
將Apache的commons-fileupload.jar放在應用程序的WEB-INF\lib下，即可使用。下面舉例介紹如何使用它的文件上傳功能。
所使用的fileUpload版本為1.2，環境為Eclipse3.3+MyEclipse6.0。FileUpload 是基于 Commons IO的，所以在進入項目前先確定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載。
示例1
最簡單的例子，通過ServletFileUpload靜態類來解析Request，工廠類FileItemFactory會對mulipart類的表單中的所有字段進行處理，不只是file字段。getName（）得到文件名，getString（）得到表單數據內容，isFormField（）可判斷是否為普通的表單項。
demo1.html
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<html><head> <meta http-equiv="Content-Type" content="text/html; charset=GB18030"> <title>File upload</title></head><body> //必須是multipart的表單數據。 <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
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<%@ 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);//檢查輸入請求是否為multipart表單數據。 if (isMultipart == true) { FileItemFactory factory = new DiskFileItemFactory();//為該請求創建一個DiskFileItemFactory對象，通過它來解析請求。執行解析后，所有的表單項目都保存在一個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(); //檢查當前項目是普通表單項目還是上傳文件。 if (item.isFormField()) {//如果是普通表單項目，顯示表單內容。 String fieldName = item.getFieldName(); if (fieldName.equals("name")) //對應demo1.html中type="text" name="name" out.print("the field name is" + item.getString());//顯示表單內容。 out.print("<br>"); } else {//如果是上傳文件，顯示文件名。 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> |
結果：
the field name isjeff
the upload file name isD:\C語言考試樣題\作業題.rar
示例2
上傳兩個文件到指定的目錄。
demo2.html
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<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
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<%@ 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()){//依次處理每個文件 FileItem item=(FileItem)itr.next(); String fileName=item.getName();//獲得文件名，包括路徑 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> |
結果：
upload succeed
此時，在"D:\temp"下可以看到你上傳的兩個文件。
示例3
上傳一個文件到指定的目錄，并限定文件大小。
demo3.html
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<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
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<%@ 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");//上傳文件目錄 if (!uploadPath.exists()) { uploadPath.mkdirs(); } // 臨時文件目錄 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); // 設置緩沖區大小，這里是4kb factory.setRepository(tempPathFile);//設置緩沖區目錄 // Create a new file upload handler ServletFileUpload upload = new ServletFileUpload(factory); // Set overall request size constraint upload.setSizeMax(4194304); // 設置最大文件尺寸，這里是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來實現文件上傳。
Upload.java
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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"; // 上傳文件的目錄 private String tempPath = "d:\\temp\\buffer\\"; // 臨時文件目錄 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); // 設置緩沖區大小，這里是4kb factory.setRepository(tempPathFile);// 設置緩沖區目錄 // Create a new file upload handler ServletFileUpload upload = new ServletFileUpload(factory); // Set overall request size constraint upload.setSizeMax(4194304); // 設置最大文件尺寸，這里是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) { // 可以跳轉出錯頁面 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
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<html><head> <meta http-equiv="Content-Type" content="text/html; charset=GB18030"> <title>File upload</title></head><body>// action="fileupload"對應web.xml中<servlet-mapping>中<url-pattern>的設置. <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
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<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內容，希望對大家的學習有所幫助，也希望大家多多支持服務器之家。
原文鏈接：http://zhangjunhd.blog.51cto.com/113473/18331/
