使用fileupload实现文件上传，并自动生成不同的文件夹

分手后的思念是犯贱 2022-12-31 01:09 137阅读 0赞

package cn.itcast.servlet; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.List; import java.util.Random; import java.util.UUID; import javax.servlet.ServletException; 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; public class Servlet1 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); // 获得表单参数 name=zhangsan&password=123 // 1. 创建解析工厂 DiskFileItemFactory factory = new DiskFileItemFactory(); // factory.setSizeThreshold(12); 默认 10 k 缓存大小 // factory.setRepository(new File("d:\\temp2")); // 指定临时文件的存放目录 // 2. 创建用于解析request的FileUpload ServletFileUpload upload = new ServletFileUpload(factory); // 3. 判断一下是否是文件上传表单 if(!upload.isMultipartContent(request)) { request.setAttribute("message", "不是文件上传表单"); request.getRequestDispatcher("/message.jsp").forward(request, response); return; } // 4. 解析 List<FileItem> fileitems = null; try { fileitems = upload.parseRequest(request); } catch (FileUploadException e) { throw new RuntimeException(e); } // 5. 遍历 for(FileItem item : fileitems) { // 判断是否为普通字段 if(item.isFormField()) { // 获得字段的name和value String name = item.getFieldName(); String value = item.getString("utf-8"); System.out.println(name + "=" + value); } else { // 上传字段 // 获得字段名 String name = item.getFieldName(); // 获得文件名 String filename = item.getName(); // System.out.println("before: " + filename); filename = filename.substring(filename.lastIndexOf("\\")+1); // System.out.println("after: " + filename); System.out.println("filename=" + filename); // 将文件名加上唯一的标识 保证文件名不重复 filename = UUID.randomUUID().toString() + "_" + filename; // a_b_c.jpg System.out.println("filename=" + filename); // 约定一个文件的存放目录 获得目录绝对路径 String dirPath = getServletContext().getRealPath("/WEB-INF/upload"); // 分目录 将文件打散 // 按照时间存放 年 月 日 /* 产生随机数 作为目录 弊端 将来无法查找 Random r = new Random(); int num = r.nextInt(16); dirPath = dirPath + "\\" + num; num = r.nextInt(16); dirPath = dirPath + "\\" + num; */ // 文件夹最好按照文件名来计算 int hashCode = filename.hashCode(); // 010100111110110101010010101 int num = hashCode&0x0000000f; dirPath = dirPath + "\\" + num; // 二级目录 再拿高的四位 取值 0~15 相当于获得了随机数 只不过是计算出来的 num = (hashCode>>4)&0x0000000f; dirPath = dirPath + "\\" + num; //　创建必要的文件夹 File dir = new File(dirPath); dir.mkdirs(); // 创建文件对象 File file = new File(dir, filename); // 创建文件 file.createNewFile(); // 获得流 InputStream in = item.getInputStream(); OutputStream out = new FileOutputStream(file); // 流的对拷 int len; byte[] buffer = new byte[1024]; while((len=in.read(buffer))>0) out.write(buffer, 0, len); in.close(); out.close(); // 删除临时文件 在这之前需要关闭输入输出流 item.delete(); } } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }