需要 commons-io与commons-fileupload
首先在jsp中创建一下布局
<%@ page contentType="text/html;charset=UTF-8" language="java"%><html><head><title>$Title$</title></head><body><form action="MyServlet" method="post" enctype="multipart/form-data">最简单的文件上传：<input type="file" name="fileupload"/>描述：<input type="text" name="desc"/><input type="submit" value="submit"/></form></body></html>
然后创建一个servlet类
并在dopost方法中写入上传文件代码
request.setCharacterEncoding("UTF-8");response.setCharacterEncoding("UTF-8");//1、创建一个DiskFileItemFactory工厂DiskFileItemFactory factory =newDiskFileItemFactory();//2、创建一个文件上传解析器ServletFileUpload upload =newServletFileUpload(factory);//解决上传文件名的中文乱码upload.setHeaderEncoding("UTF-8");factory.setSizeThreshold(1024*500);//设置内存的临界值为500KFile linshi =newFile("E:\linshi");//当超过500K的时候，存到一个临时文件夹中factory.setRepository(linshi);upload.setSizeMax(1024*1024*5);//设置上传的文件总的大小不能超过5Mtry{// 1. 得到 FileItem 的集合 itemsList<FileItem>/* FileItem */items = upload.parseRequest(request);// 2. 遍历 items:for(FileItem item : items){// 若是一个一般的表单域, 打印信息if(item.isFormField()){String name = item.getFieldName();String value = item.getString("utf-8");System.out.println(name +": "+ value);}// 若是文件域则把文件保存到 e:\files 目录下.else{String fileName = item.getName();long sizeInBytes = item.getSize();System.out.println(fileName);System.out.println(sizeInBytes);InputStream in = item.getInputStream();byte[] buffer =newbyte[1024];int len =0;fileName ="e:\files\"+ fileName;//文件最终上传的位置System.out.println(fileName);OutputStream out =newFileOutputStream(fileName);while((len = in.read(buffer))!=-1){out.write(buffer,0, len);}out.close();in.close();}}}catch(FileUploadException e){e.printStackTrace();}