1 案例分析
1 文件上传原理分析
2 代码实现
1 form.html
vf<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Insert title here</title></head><body> ???<form action="/WEB32/fileuploadServlet2" method="post" enctype="multipart/form-data"> ???????<input type="text" name="username"><br> ???????<input type="file" name="filename"><br> ???????<input type="submit" value="上传文件"> ???</form></body></html>
2 FileuploadServlet代码
public class FileuploadServlet extends HttpServlet { ???public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ???????????????????????try { ???????????//接受上传文件 ???????????????????????//1、创建磁盘文件项工厂 ???????????DiskFileItemFactory factory = new DiskFileItemFactory(); ???????????//2、创建文件上传的核心类 ???????????ServletFileUpload upload = new ServletFileUpload(factory); ???????????????????????//3、解析request---获得文件项集合 ???????????List<FileItem> parseRequest = upload.parseRequest(request); ???????????//4、遍历文件项集合 ???????????for(FileItem item : parseRequest){ ???????????????//5、判断普通表单项/文件上传项 ???????????????boolean formField = item.isFormField();//是否是一个普通表单项 ???????????????if(formField){ ???????????????????//普通表单项 ???????????????????String fieldName = item.getFieldName(); ???????????????????String fieldValue = item.getString(); ???????????????????System.out.println(fieldName+":"+fieldValue); ???????????????}else{ ???????????????????//文件上传项 ???????????????????//获得上传文件的名称 ???????????????????String fileName = item.getName(); ???????????????????//获得上传文件的内容 ???????????????????InputStream in = item.getInputStream(); ???????????????????//将in中的数据拷贝服务器上 ???????????????????String path = this.getServletContext().getRealPath("upload"); ???????????????????OutputStream out = new FileOutputStream(path+"/"+fileName); ???????????????????int len = 0; ???????????????????byte[] buffer = new byte[1024]; ???????????????????while((len=in.read(buffer))>0){ ???????????????????????out.write(buffer, 0, len); ???????????????????} ???????????????????????????????????????in.close(); ???????????????????out.close(); ???????????????} ???????????} ???????????????????????????????} catch (FileUploadException e) { ???????????e.printStackTrace(); ???????} ?????} ???public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ???????doGet(request, response); ???}}3 FileuploadServlet2代码
public class FileuploadServlet2 extends HttpServlet { ???public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ???????try { ???????????//1、创建磁盘文件项工厂 ???????????//作用：设置缓存文件的大小 ?设置临时文件存储的位置 ???????????String path_temp = this.getServletContext().getRealPath("temp"); ???????????//DiskFileItemFactory factory = new DiskFileItemFactory(1024*1024, new File(path_temp)); ???????????DiskFileItemFactory factory = new DiskFileItemFactory(); ???????????factory.setSizeThreshold(1024*1024); ???????????factory.setRepository(new File(path_temp)); ???????????//2、创建文件上传的核心类 ???????????ServletFileUpload upload = new ServletFileUpload(factory); ???????????//设置上传文件的名称的编码 ???????????upload.setHeaderEncoding("UTF-8"); ???????????//ServletFileUpload的API ???????????boolean multipartContent = upload.isMultipartContent(request);//判断表单是否是文件上传的表单 ???????????if(multipartContent){ ???????????????//是文件上传的表单 ???????????????//***解析request获得文件项集合 ???????????????List<FileItem> parseRequest = upload.parseRequest(request); ???????????????if(parseRequest!=null){ ???????????????????for(FileItem item : parseRequest){ ???????????????????????//判断是不是一个普通表单项 ???????????????????????boolean formField = item.isFormField(); ???????????????????????if(formField){ ???????????????????????????//username=zhangsan ???????????????????????????String fieldName = item.getFieldName(); ???????????????????????????String fieldValue = item.getString("UTF-8");//对普通表单项的内容进行编码 ???????????????????????????????????????????????????????System.out.println(fieldName+"----"+fieldValue); ???????????????????????????????????????????????????????//当表单是enctype="multipart/form-data"时 request.getParameter相关的方法 ???????????????????????????//String parameter = request.getParameter("username"); ???????????????????????????????????????????????????}else{ ???????????????????????????//文件上传项 ???????????????????????????//文件的名 ???????????????????????????String fileName = item.getName(); ???????????????????????????//获得上传文件的内容 ???????????????????????????InputStream in = item.getInputStream(); ???????????????????????????String path_store = this.getServletContext().getRealPath("upload"); ???????????????????????????OutputStream out = new FileOutputStream(path_store+"/"+fileName); ???????????????????????????IOUtils.copy(in, out); ???????????????????????????in.close(); ???????????????????????????out.close(); ???????????????????????????????????????????????????????//删除临时文件 ???????????????????????????item.delete(); ???????????????????????????????????????????????????} ???????????????????} ???????????????} ???????????}else{ ???????????????//不是文件上传表单 ???????????????//使用原始的表单数据的获得方式 request.getParameter(); ???????????} ???????} catch (FileUploadException e) { ???????????e.printStackTrace(); ???????} ???} ???public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ???????doGet(request, response); ???}}3 文件上传知识点
案例34-文件上传
原文地址：https://www.cnblogs.com/jepson6669/p/8449541.html