我是一名初学jsp菜鸟，今天就把自己所写的jsp上传文件的代码给大家分享一下，希望和大家多多交流，互相学习。望指教！
一、单纯的上传文件
1 <% 2 ????????request.setCharacterEncoding("utf-8"); 3 ????????String uploadFileName=""; ???//上传的文件名 4 ????????String fieldName=""; ???????????//表单字段元素的name属性值 5 ????????//请求信息中的内容是否是multipart类型 6 ????????boolean isMultipart=ServletFileUpload.isMultipartContent(request); 7 ????????//上传文件的存储路径(服务器文件系统上的绝对文件路径) 8 ????????String uploadFilePath=request.getSession().getServletContext().getRealPath("upload/"); 9 ????????if(isMultipart){10 ????????????FileItemFactory factory=new DiskFileItemFactory();11 ????????????ServletFileUpload upload=new ServletFileUpload(factory);12 ????????????try{13 ????????????????//解析form表单中所有文件14 ????????????????List<FileItem> items=upload.parseRequest(request);15 ????????????????Iterator<FileItem> iter=items.iterator();16 ????????????????while(iter.hasNext()){ ???????//依次处理每个文件17 ????????????????????FileItem item=(FileItem)iter.next();18 ????????????????????if(item.isFormField()){ ???????//普通表单字段19 ????????????????????????fieldName=item.getFieldName(); ???????//表单字段的name属性值20 ????????????????????????if("user".equals(fieldName)){21 ????????????????????????????//输出表单字段的值22 ????????????????????????????out.print(item.getString("utf-8")+"上传了文件<br/>");23 ????????????????????????}24 ????????????????????}else{ ???//文件表单字段25 ????????????????????????String fileName=item.getName();26 ????????????????????????if(fileName!=null&&!"".equals(fileName)){27 ????????????????????????????File fullFile=new File(item.getName());28 ????????????????????????????File saveFile=new File(uploadFilePath,fullFile.getName());29 ????????????????????????????item.write(saveFile);30 ????????????????????????????uploadFileName=fullFile.getName();31 ????????????????????????????out.print("上传成功后的文件名是："+uploadFileName);32 ????????????????????????}33 ????????????????????}34 ????????????????}35 ????????????}catch(Exception e){36 ????????????????e.printStackTrace();37 ????????????}38 ????????}39 ?????%> 二、上传指定格式的文件
<%request.setCharacterEncoding("utf-8"); ???String uploadFileName="";//上传的文件名 ???String fieldName="";//表单字段元素的name属性值 ???//请求信息中的内容是否是multipart类型 ???boolean isMultipart=ServletFileUpload.isMultipartContent(request); ???//上传文件的存储路径(服务器文件系统上的绝对文件路径) ???String uploadFilePath=request.getSession().getServletContext().getRealPath("upload/"); ???if(isMultipart){ ???FileItemFactory factory=new DiskFileItemFactory(); ???ServletFileUpload upload=new ServletFileUpload(factory); ???try{ ???//解析form表单中所有文件 ???List<FileItem> items=upload.parseRequest(request); ???Iterator<FileItem> iter=items.iterator(); ???while(iter.hasNext()){//依次处理每个文件 ???FileItem item=(FileItem)iter.next(); ???if(item.isFormField()){//普通表单字段 ???fieldName=item.getFieldName();//表单字段的name属性值 ???if("user".equals(fieldName)){ ???//输出表单字段的值 ???out.print(item.getString("utf-8")+"上传了文件<br/>"); ???} ???}else{//文件表单字段 ???String fileName=item.getName(); ???//通过Arrays类的asList()方法创建固定长度的集合 ???List<String> fileType=Arrays.asList("gif","bmp","jpg"); ???String ext=fileName.substring(fileName.lastIndexOf(".")+1); ???if(!fileType.contains(ext)){//判断文件类型是否在允许的范围类 ???out.print("上传失败，文件类型只能是gif、bmp、jpg"); ???}else{ ???if(fileName!=null&&!"".equals(fileName)){ ???File fullFile=new File(item.getName()); ???File saveFile=new File(uploadFilePath,fullFile.getName()); ???item.write(saveFile); ???uploadFileName=fullFile.getName(); ???out.print("上传成功后的文件名是："+uploadFileName); ???} ???} ???} ???} ???}catch(Exception e){ ???e.printStackTrace(); ???} ???} ??%> 三、上传指定格式的文件并限制文件大小
?<%request.setCharacterEncoding("utf-8"); ???String uploadFileName="";//上传的文件名 ???String fieldName="";//表单字段元素的name属性值 ???//请求信息中的内容是否是multipart类型 ???boolean isMultipart=ServletFileUpload.isMultipartContent(request); ???//上传文件的存储路径(服务器文件系统上的绝对文件路径) ???String uploadFilePath=request.getSession().getServletContext().getRealPath("upload/"); ???//创建临时文件目录路径 ???File tempPatchFile=new File("d:/temp/buffer/"); ???if(!tempPatchFile.exists()){ ???tempPatchFile.mkdirs();//创建指定的目录，包括所有必须但不存在的父目录 ???} ???if(isMultipart){ ???DiskFileItemFactory factory=new DiskFileItemFactory(); ???//设置缓冲区大小4kb ????factory.setSizeThreshold(4096); ???//设置上传文件用到临时文件存放路径 ???factory.setRepository(tempPatchFile); ???ServletFileUpload upload=new ServletFileUpload(factory); ???//设置一个完整请求的最大允许大小 ???upload.setSizeMax(1024*1200); ???try{ ???//解析form表单中所有文件 ???List<FileItem> items=upload.parseRequest(request); ???Iterator<FileItem> iter=items.iterator(); ???while(iter.hasNext()){//依次处理每个文件 ???FileItem item=(FileItem)iter.next(); ???if(item.isFormField()){//普通表单字段 ???fieldName=item.getFieldName();//表单字段的name属性值 ???if("user".equals(fieldName)){ ???//输出表单字段的值 ???out.print(item.getString("utf-8")+"上传了文件<br/>"); ???} ???}else{//文件表单字段 ???String fileName=item.getName(); ???//通过Arrays类的asList()方法创建固定长度的集合 ???List<String> fileType=Arrays.asList("gif","bmp","jpg"); ???String ext=fileName.substring(fileName.lastIndexOf(".")+1); ???if(!fileType.contains(ext)){//判断文件类型是否在允许的范围类 ???out.print("上传失败，文件类型只能是gif、bmp、jpg"); ???}else{ ???if(fileName!=null&&!"".equals(fileName)){ ???File fullFile=new File(item.getName()); ???File saveFile=new File(uploadFilePath,fullFile.getName()); ???item.write(saveFile); ???uploadFileName=fullFile.getName(); ???out.print("上传成功后的文件名是："+uploadFileName+",文件大小是："+item.getSize()+"bytes!"); ???} ???} ???} ???} ???}catch(FileUploadBase.SizeLimitExceededException ex){ ???out.print("上传失败，文件太大，全部文件的最大限制是："+upload.getSizeMax()+"bytes!"); ???}catch(Exception e){ ???e.printStackTrace(); ???} ???} ??%>jsp上传文件
原文地址：https://www.cnblogs.com/ggl5250703/p/8412834.html