Apache Commons fileUpload文件上传多个示例分享

2019-11-26 13:42:53

字体：大中小

来源：转载

供稿：网友

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武林网。

上一篇：java组件commons-fileupload文件上传示例

下一篇：java组件fileupload文件上传demo