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文件上传组件
1 Apache的Commons FileUpload
2 JavaZoom的UploadBean
3 jspSmartUpload
FileUpload下载网址:
http://commons.apache.org/fileupload/
步骤:
1 导入Apache的Commons FileUpload组件的两个jar包
2 建上传页面
<form action="servlet/upload" method="post" enctype="multipart/form-data" name="form1">
  上传人:<input type="text" name="username"/><br/>
  上传文件:<input type="file" name="loadname"/><br/>
  <input type="submit"/>
</form>
注意,form中enctype="multipart/form-data"属性为上传属性,必写
---------------------------------------------------------------------
3 建立servlet处理类
public class UploadServlet extends HttpServlet {
 private ServletContext sc;//ServletContext定义了一系列方法用于与相应的servlet容器通信
 private String savePath;

 public void init(ServletConfig config) throws ServletException {
  savePath = config.getInitParameter("savePath");//得到初始化信息
  sc = config.getServletContext();//得到ServletContext接口的实例
 }

 private static final long serialVersionUID = 7093971456528100363L;

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  doPost(request, response);
 }

 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  request.setCharacterEncoding("UTF-8");
  DiskFileItemFactory factory = new DiskFileItemFactory();
  ServletFileUpload upload = new ServletFileUpload(factory);
  try {
   List items = upload.parseRequest(request);
   for (int i = 0; i < items.size(); i++) {
    FileItem item = (FileItem) items.get(i);
    if (item.isFormField()) {
     System.out.println("表单的参数名称:" + item.getFieldName()
       + ",对应的参数值:" + item.getString("UTF-8"));
    } else {
     if (item.getName() != null && !item.getName().equals("")) {
      System.out.println("上传文件的大小:" + item.getSize());
      System.out.println("上传文件的类型:" + item.getContentType());
      System.out.println("上传文件的名称:" + item.getName());

      File temFile = new File(item.getName());
      File file = new File(sc.getRealPath("/") + savePath,
        temFile.getName());
      item.write(file);

      request.setAttribute("upload.message", "上传文件成功!");
     } else {
      request.setAttribute("upload.message", "没有上传文件成功!");
     }
    }
   }
  } catch (Exception e) {
   e.printStackTrace();
   request.setAttribute("upload.message", "没有上传文件成功!");
  }
  request.getRequestDispatcher("/uploadresult.jsp").forward(request, response);
 }
}
-----------------------------------------------------------------------------------
4 配置web.xml
<servlet>
    <servlet-name>UploadServlet</servlet-name>
    <servlet-class>com.webs.UploadServlet</servlet-class>
    <init-param>
    <param-name>savePath</param-name>
    <param-value>uploads</param-value>
    </init-param>
  </servlet>

  <servlet-mapping>
    <servlet-name>UploadServlet</servlet-name>
    <url-pattern>/servlet/upload</url-pattern>
  </servlet-mapping>


-----------------------------------------------------------------------------------
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Apache的commons-fileupload.jar可方便的实现文件的上传功能,本文通过实例来介绍如何使用commons-fileupload.jar。
@author:ZJ 07-2-22
Blog: http://zhangjunhd.blog.51cto.com/
    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>

posted on 2009-11-29 21:34 junly 阅读(314) 评论(0)  编辑  收藏 所属分类: java

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