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Apache Commons fileUpload實現文件上傳

  Apache的commons-fileupload.jar可方便的實現文件的上傳功能，本文通過實例來介紹如何使用commons-fileupload.jar。

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。
      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。
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

<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

<%@ 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

<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>
示例3
上傳一個文件到指定的目錄，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
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

<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
<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>

以上轉帖
本文出自 “子孑” 博客，請務必保留此出處http://zhangjunhd.blog.51cto.com/113473/18331
link

posted on 2008-11-06 12:11 greedy 閱讀(1444) 評論(0) 編輯收藏

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