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Apache Commons fileUpload文件上传多个示例分享

程序员文章站 2024-03-12 12:09:02
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...

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。

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