javaweb实现文件上传示例代码

2024-07-13 10:06:14

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本文实例为大家分享了javaweb文件下载的具体实现代码，供大家参考，具体内容如下

文件上传示例

注意：jsp页面编码为"UTF-8"

文件上传的必要条件

1.form表单，必须为POST方式提交

2.enctype="multipart/form-data"

3.必须有<input type="file" />

前端jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head> <base href="<%=basePath%>" rel="external nofollow" >  <title>My JSP 'index.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0">  <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" > --> </head> <script type="text/javascript">  function addFile(){   var div1=document.getElementById("div1");   div1.innerHTML+="<div><input type='file' /><input type='button' value='删除' onclick='deleteFile(this)' /> <br/></div>";    }  function deleteFile(div){   //他的爷爷删除他的爸爸   div.parentNode.parentNode.removeChild(div.parentNode);    } </script> <body>  <form action="${pageContext.request.contextPath }/servlet/upLoadServlet" method="post" enctype="multipart/form-data">  文件的描述：<input type="text" name ="description" /><br/>  <div id="div1">   <div>   <input type="file" name ="file" /><input type="button" value="添加" onclick="addFile()" /><br/>   </div>     </div>    <input type="submit" />  </form> </body></html>

实现文件上传的servlet

package com.learning.servlet;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.UnsupportedEncodingException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.List;import java.util.UUID;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;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.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;import org.apache.commons.io.FilenameUtils;/** * Servlet implementation class UpLoadServlet */@WebServlet("/servlet/upLoadServlet")public class UpLoadServlet extends HttpServlet { private static final long serialVersionUID = 1L; /**  * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)  */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  doGet(request, response); } /**  * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)  */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {       //文件上传  //判断是否支持文件上传  boolean isMultipartContent = ServletFileUpload    .isMultipartContent(request);  if (!isMultipartContent) {   throw new RuntimeException("不支持");  }    // 创建一个DiskFileItemfactory工厂类  DiskFileItemFactory diskFileItemFactory=new DiskFileItemFactory();  // 创建一个ServletFileUpload核心对象  ServletFileUpload fileUpload=new ServletFileUpload(diskFileItemFactory);  //设置中文乱码  fileUpload.setHeaderEncoding("UTF-8");  //设置一个文件大小  fileUpload.setFileSizeMax(1024*1024*3); //大小为3M  //设置总文件大小  //fileUpload.setSizeMax(1024*1024*10);//大小为10M    try {   //fileload解析request请求，返回list<FileItem>集合   List<FileItem> fileItems = fileUpload.parseRequest(request);   for (FileItem fileItem : fileItems) {    if (fileItem.isFormField()) {     //是文本域 (处理文本域的函数)     processFormField(fileItem);    }else {     //文件域 (处理文件域的函数)     processUpLoadField1(fileItem);    }   }     } catch (FileUploadException e) {   e.printStackTrace();  }     } /**  * @param fileItem  *   */ private void processUpLoadField1(FileItem fileItem) {    try {   //获得文件读取流   InputStream inputStream = fileItem.getInputStream();      //获得文件名   String fileName = fileItem.getName();      //对文件名处理   if (fileName!=null) {    fileName.substring(fileName.lastIndexOf(File.separator)+1);       }else {    throw new RuntimeException("文件名不存在");   }      //对文件名重复处理//   fileName=new String(fileName.getBytes("ISO-8859-1"),"UTF-8");   fileName=UUID.randomUUID()+"_"+fileName;      //日期分类   SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd");   String date = simpleDateFormat.format(new Date());   //创建目录   File parent=new File(this.getServletContext().getRealPath("/WEB-INF/upload/"+date));   if (!parent.exists()) {    parent.mkdirs();   }      //上传文件   fileItem.write(new File(parent, fileName));   //删除临时文件（如果上传文件过大，会产生.tmp的临时文件）   fileItem.delete();     } catch (IOException e) {   System.out.println("上传失败");   e.printStackTrace();  } catch (Exception e) {     }       } /**  * @param fileItem  */ //文件域 private void processUpLoadField(FileItem fileItem) {     try {   //获得文件输入流   InputStream inputStream = fileItem.getInputStream();      //获得是文件名字   String filename = fileItem.getName();   //对文件名字处理   if (filename!=null) {//    filename.substring(filename.lastIndexOf(File.separator)+1);    filename = FilenameUtils.getName(filename);   }      //获得路径，创建目录来存放文件   String realPath = this.getServletContext().getRealPath("/WEB-INF/load");      File storeDirectory=new File(realPath);//既代表文件又代表目录   //创建指定目录   if (!storeDirectory.exists()) {    storeDirectory.mkdirs();   }   //防止文件名一样   filename=UUID.randomUUID()+"_"+filename;   //目录打散 防止同一目录文件下文件太多，不好查找      //按照日期分类存放上传的文件   //storeDirectory = makeChildDirectory(storeDirectory);      //多级目录存放上传的文件   storeDirectory = makeChildDirectory(storeDirectory,filename);      FileOutputStream fileOutputStream=new FileOutputStream(new File(storeDirectory, filename));   //读取文件，输出到指定的目录中   int len=1;   byte[] b=new byte[1024];   while((len=inputStream.read(b))!=-1){    fileOutputStream.write(b, 0, len);   }   //关闭流   fileOutputStream.close();   inputStream.close();      } catch (IOException e) {   e.printStackTrace();  }  } //按照日期来分类 private File makeChildDirectory(File storeDirectory) {  SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd");  String date = simpleDateFormat.format(new Date());  //创建目录  File childDirectory=new File(storeDirectory, date);  if (!childDirectory.exists()) {   childDirectory.mkdirs();  }  return childDirectory; }  //多级目录 private File makeChildDirectory(File storeDirectory, String filename) {  filename=filename.replaceAll("-", "");   File childDirectory =new File(storeDirectory, filename.charAt(0)+File.separator+filename.charAt(1));  if (!childDirectory.exists()) {   childDirectory.mkdirs();    }  return childDirectory; } //文本域 private void processFormField(FileItem fileItem) {  //对于文本域的中文乱码，可以用new String()方式解决   try {    String fieldName = fileItem.getFieldName();//表单中字段名name，如description    String fieldValue = fileItem.getString("UTF-8");//description中value//    fieldValue=new String(fieldValue.getBytes("ISO-8859-1"),"UTF-8");    System.out.println(fieldName +":"+fieldValue);   } catch (UnsupportedEncodingException e) {    // TODO Auto-generated catch block    e.printStackTrace();   }    }}

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