文件上传（不使用Jar包）

矫情吗；* 2022-05-29 10:15 220阅读 0赞

原文连接：[http://blog.csdn.net/qilin001cs/article/details/50274773][http_blog.csdn.net_qilin001cs_article_details_50274773]  
![这里写图片描述][Image 1]

<%-- @author qiyulin @date 2019 09 22 实现无依赖jar文件上传 可支持windows 和 linux 亲测无错误 --%>
    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%@page import="java.io.BufferedReader"%>
    <%@page import="java.io.StringReader"%>
    <%@page import="java.io.IOException"%>
    <%@page import="java.io.File"%>
    <%@page import="java.io.InputStream"%>
    <%@page import="java.io.ByteArrayOutputStream"%>
    <%@page import="java.io.FileOutputStream"%>
    <%@page import="java.io.PrintWriter"%>
    <%@page import="java.text.SimpleDateFormat"%>
    <%! //换行符 文件上传的换行符和系统无关！！！！ public static String LINE_SEPARATOR = "\r\n"; //System.getProperty("line.separator") //提取上传的文件头信息 private FileHeadInfo extractFileHead(String content) throws IOException { BufferedReader reader = new BufferedReader(new StringReader(content)); String multipartDelimiter, fileName, contentType,lineRead; if ((lineRead = reader.readLine()) != null) { //读取的第一行是一个分割符 multipartDelimiter = lineRead; //对分隔符分割 获取有用信息 String strs[] = content.split(multipartDelimiter); String avial = strs[strs.length-2]; reader = new BufferedReader(new StringReader(avial)); StringBuilder sb =new StringBuilder(LINE_SEPARATOR); reader.readLine();//第一行空白 if ((lineRead = reader.readLine()) != null) { //读取的第二行为：Content-Disposition: form-data; name="file1"; filename="320_442.png" fileName = new File(lineRead.split(";")[2].split("=")[1].replace('"', ' ').trim()).getName(); sb.append(lineRead+LINE_SEPARATOR); //以上为获取filename if ((lineRead = reader.readLine()) != null) { //第三行为：Content-Type: image/png contentType = lineRead.split(":")[1].trim(); sb.append(lineRead+LINE_SEPARATOR); //空白行 sb.append(LINE_SEPARATOR); //返回上传文件头的实体类 int start = 0; for(int i=0;i<(strs.length-2);i++){ String ss = multipartDelimiter+strs[i]; start+=ss.getBytes().length; } start+=sb.toString().getBytes().length; return new FileHeadInfo(multipartDelimiter,fileName, contentType,start); } } } return null; } //根目录URL private String ROOT(HttpServletRequest request){ String path = request.getRequestURI().substring(0,request.getRequestURI().lastIndexOf("/")); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; return basePath; } //根目录物理路径 private String PATH(HttpServletRequest request){ String s = request.getContextPath(); String uri = request.getRequestURI(); int last = uri.replace(s,"").lastIndexOf("/"); String mid =""; if(last!=0) mid = uri.replace(s,"").substring(1,last)+File.separator; String root = request.getSession().getServletContext().getRealPath("/")+mid; return root; } //uuid文件名 private String UUID(){ UUID uuid = UUID.randomUUID(); return uuid.toString().replace("-","").toLowerCase().substring(8,24); } //提取的上传文件信息 class FileHeadInfo { private String multipartDelimiter; //文件名 private String originalFileName; //文件的 content type private String contentType; //文件的数据 start bytes.length private int dataStart; public FileHeadInfo(String _multipartDelimiter,String _original_file_name ,String _content_type,int _data_start) { multipartDelimiter = _multipartDelimiter; originalFileName = _original_file_name; contentType = _content_type; dataStart = _data_start; } } %>
    <% if(request.getMethod().equals("POST")){ InputStream inputStream = request.getInputStream(); if (inputStream.available()!=-1) { //判断文件大小 if (request.getContentLength() > 5000000) {//5M PrintWriter pw = response.getWriter(); pw.print("{\"status\":2,\"info\":\"file length is too large\"}"); pw.close(); return; } //建立缓冲区 ByteArrayOutputStream byteOutput = new ByteArrayOutputStream(request.getContentLength()); if (inputStream != null) { int i =0; byte [] b = new byte[2048]; while((i = inputStream.read(b))!= -1){ byteOutput.write(b, 0, i); } } //字节数组 byte requestContent [] =byteOutput.toByteArray(); //转为字符串 String requestContentAsString =new String(requestContent); //获取报头所携带的文件信息 FileHeadInfo headerBean = extractFileHead(requestContentAsString); //检查文件的扩展名 if (!(headerBean.originalFileName.toLowerCase().indexOf(".jpg") !=-1|| headerBean.originalFileName.toLowerCase().indexOf(".png") !=-1|| headerBean.originalFileName.toLowerCase().indexOf(".gif") !=-1|| headerBean.originalFileName.toLowerCase().indexOf(".bmp") !=-1|| headerBean.originalFileName.toLowerCase().indexOf(".xls") !=-1) ){ PrintWriter pw = response.getWriter(); pw.print("{\"status\":3,\"info\":\"extension not allowed\"}"); pw.close(); return; } //检查文件的content type if (!("application/vnd.ms-excel".equals(headerBean.contentType)|| "image/jpeg".equals(headerBean.contentType)|| "image/png".equals(headerBean.contentType)|| "image/gif".equals(headerBean.contentType)|| "image/bmp".equals(headerBean.contentType) )){ PrintWriter pw = response.getWriter(); pw.print("{\"status\":4,\"info\":\"content type is invalid\"}"); pw.close(); return; } //获取文件内容 String root = PATH(request)+"uploads"+File.separator; String yyyymm= new SimpleDateFormat("yyyy-MM").format(new Date()); File path = new File(root+yyyymm); String filename =UUID()+headerBean.originalFileName.substring(headerBean.originalFileName.lastIndexOf(".")); if(!path.exists()) path.mkdir(); //把文件写到本地 FileOutputStream fileOut = new FileOutputStream(new File(path,filename)); //wirte int end =requestContent.length-headerBean.dataStart-headerBean.multipartDelimiter.getBytes().length-"--".getBytes().length-LINE_SEPARATOR.getBytes().length; fileOut.write(requestContent,headerBean.dataStart,end); fileOut.flush(); fileOut.close(); //out PrintWriter pw = response.getWriter(); pw.print("{\"status\":1,\"info\":\""+ROOT(request)+"uploads/"+yyyymm+"/"+filename+"\"}"); pw.close(); }else{ PrintWriter pw = response.getWriter(); pw.print("{\"status\":0,\"info\":\"file can not be empty\"}"); pw.close(); } } %>

[http_blog.csdn.net_qilin001cs_article_details_50274773]: http://blog.csdn.net/qilin001cs/article/details/50274773
[Image 1]: