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 程式師世界 >> 編程語言 >> JAVA編程 >> 關於JAVA >> Apache Commons fileUpload實現文件上傳

Apache Commons fileUpload實現文件上傳

編輯:關於JAVA

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 是基於 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後的附件中下載。

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

<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。執行解析後,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>

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,並限定文件大小。

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,這裡是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,這裡是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,這裡是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,這裡是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>

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

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