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java组件commons-fileupload实现文件上传

程序员文章站 2024-03-12 23:25:38
一、所需要的包： 1、commons-fileupload-1.2.1.jar： 下载地址 2、commons-io-1.4.jar： 下载地址...

一、所需要的包：
1、commons-fileupload-1.2.1.jar：
下载地址

2、commons-io-1.4.jar：
下载地址

二、注意事项：
form表单里面要加上enctype="multipart/form-data" 

三、代码示例 

1、jsp代码：

<%@ page language="java" contenttype="text/html; charset=utf-8" 
 pageencoding="utf-8"%> 
<!doctype html public "-//w3c//dtd html 4.01 transitional//en" "http://www.w3.org/tr/html4/loose.dtd"> 
<html> 
<head> 
<meta http-equiv="content-type" content="text/html; charset=utf-8"> 
<title>upload</title> 
</head> 
<body> 
<form action="uploadservlet" method="post" enctype="multipart/form-data"> 
 <table> 
 <caption>上传实例</caption> 
 <tr> 
  <td>姓名</td> 
  <td> 
  <input type="text" name="name"> 
  </td> 
 </tr> 
 <tr> 
  <td>年龄</td> 
  <td> 
  <input type="text" name="age"> 
  </td> 
 </tr> 
 <tr> 
  <td>照片</td> 
  <td> 
  <input type="file" name="image"> 
  </td> 
 </tr> 
 <tr> 
  <td></td> 
  <td> 
  <input type="submit" value="提交"> 
  </td> 
 </tr> 
 </table> 
</form> 
</body> 
</html>

2、uploadservlet代码

package servlet; 
 
import java.io.bufferedinputstream; 
import java.io.bufferedoutputstream; 
import java.io.file; 
import java.io.fileoutputstream; 
import java.io.ioexception; 
import java.io.writer; 
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.fileuploadexception; 
import org.apache.commons.fileupload.fileuploadbase.sizelimitexceededexception; 
import org.apache.commons.fileupload.disk.diskfileitemfactory; 
import org.apache.commons.fileupload.servlet.servletfileupload; 
import org.apache.commons.fileupload.util.streams; 
 
/** 
 * 上传servlet 
 * @author lisanlai 
 * 
 */ 
public class uploadservlet extends httpservlet { 
 private static final long serialversionuid = 1l; 
  
 public uploadservlet() { 
 super(); 
 } 
 
 protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception { 
 this.dopost(request, response); 
 } 
 
 @suppresswarnings("unchecked") 
 protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception { 
  
 response.setcontenttype("text/html"); 
 // 设置字符编码为utf-8, 这样支持汉字显示 
 response.setcharacterencoding("utf-8"); 
 writer o = response.getwriter(); 
  
 /** 
  * 首先判断form的enctype是不是multipart/form-data 
  * 同时也判断了form的提交方式是不是post 
  * 方法：ismultipartcontent(request) 
  */ 
 
 if(servletfileupload.ismultipartcontent(request)){ 
  request.setcharacterencoding("utf-8"); 
  
  // 实例化一个硬盘文件工厂,用来配置上传组件servletfileupload 
  diskfileitemfactory factory = new diskfileitemfactory(); 
  
  //设置文件存放的临时文件夹，这个文件夹要真实存在 
  file filedir = new file("../webapps/fileupload/tmp/"); 
  if(filedir.isdirectory() && filedir.exists()==false){ 
  filedir.mkdir(); 
  } 
  factory.setrepository(filedir); 
  
  //设置最大占用的内存 
  factory.setsizethreshold(1024000); 
  
  //创建servletfileupload对象 
  servletfileupload sfu = new servletfileupload(factory); 
  sfu.setheaderencoding("utf-8"); 
  
  //设置单个文件最大值byte 
  sfu.setfilesizemax(102400000); 
  
  //所有上传文件的总和最大值byte 
  sfu.setsizemax(204800000); 
  
  list<fileitem> items = null; 
  
  try { 
  items = sfu.parserequest(request); 
  }catch (sizelimitexceededexception e) { 
  system.out.println("文件大小超过了最大值"); 
  } catch(fileuploadexception e) { 
  e.printstacktrace(); 
  } 
  
  //取得items的迭代器 
  iterator<fileitem> iter = items==null?null:items.iterator(); 
  
  //图片上传后存放的路径目录 
  file images = new file("d:/upload/images/"); 
  if(images.exists()==false){ 
  images.mkdirs(); 
  } 
  //迭代items 
  while(iter!=null && iter.hasnext()){ 
  fileitem item = (fileitem) iter.next(); 
   
  //如果传过来的是普通的表单域 
  if(item.isformfield()){ 
   system.out.print("普通的表单域:"); 
   system.out.print(new string(item.getfieldname()) + " "); 
   system.out.println(new string(item.getstring("utf-8"))); 
  } 
  //文件域 
  else if(!item.isformfield()){ 
   system.out.println("源图片:" + item.getname()); 
   string filename = item.getname().substring(item.getname().lastindexof("\\")); 
   bufferedinputstream in = new bufferedinputstream(item.getinputstream()); 
   //文件存储在d:/upload/images目录下,这个目录也得存在 
   bufferedoutputstream out = new bufferedoutputstream( 
    new fileoutputstream(new file(images.getabsolutepath()+ filename))); 
   streams.copy(in, out, true); 
   o.write("文件上传成功"); 
  } 
  } 
 }else { 
  system.out.println("表单的enctype 类型错误"); 
 } 
 } 
 
}

3、web.xml

<?xml version="1.0" encoding="utf-8"?> 
<web-app xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemalocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="webapp_id" version="2.5"> 
 <display-name>uploadtest</display-name> 
 <welcome-file-list> 
 <welcome-file>upload.jsp</welcome-file> 
 </welcome-file-list> 
 <servlet> 
 <description></description> 
 <display-name>uploadservlet</display-name> 
 <servlet-name>uploadservlet</servlet-name> 
 <servlet-class>servlet.uploadservlet</servlet-class> 
 </servlet> 
 <servlet-mapping> 
 <servlet-name>uploadservlet</servlet-name> 
 <url-pattern>/uploadservlet</url-pattern> 
 </servlet-mapping> 
</web-app>

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