package practice;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.UnsupportedEncodingException;

 import java.util.List;

 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.FileUploadBase;

 import org.apache.commons.fileupload.FileUploadException;

 import org.apache.commons.fileupload.disk.DiskFileItemFactory;

 import org.apache.commons.fileupload.servlet.ServletFileUpload;

 import org.apache.commons.io.FilenameUtils;

 public class UploadServlet extends HttpServlet {

     public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

          //判断表单上传的方式  是否是 multipart/form-data;

         boolean ismultipartContent = ServletFileUpload.isMultipartContent(request);

         if(!ismultipartContent){

             throw new RuntimeException("your form is not multipart/form-data");

         }

         //创建一个DiskFileItemFactory工厂类

         DiskFileItemFactory factory = new DiskFileItemFactory();

         //创建一个临时文件存储的目录

         String tempPath = this.getServletContext().getRealPath("/WEB-INF/temp");

         File  tempFile = new File(tempPath);

         if(!tempFile.exists()){

             tempFile.mkdir();

         }

         factory.setRepository(tempFile);

         //创建ServletFileUoload 核心对象

         ServletFileUpload  sfu = new ServletFileUpload(factory);

         //解决文件上传乱码问题

         sfu.setHeaderEncoding("utf-8");

         try {

         sfu.setFileSizeMax(1024*1024*3);  //单个文件大小

         sfu.setSizeMax(1024*1024*6);      //总文件大小

         //遍历表单集合返回一个List<FileItem>集合

         List<FileItem> fileItems = sfu.parseRequest(request);

         for(FileItem fileItem:fileItems){

             //判断是普通表单还是上传表单

             if(fileItem.isFormField()){

                 //按照普通表单处理

                 processFormField(fileItem);

             }else{

                 //按照上传表单来处理

                 processUploadField(fileItem);

             }

         }

         }catch(FileUploadBase.FileSizeLimitExceededException e){

             e.printStackTrace();

             request.setAttribute("message", "单个文件超出最大值");

             request.getRequestDispatcher("/uploadSong.jsp").forward(request, response);

             return;

         }catch(FileUploadBase.SizeLimitExceededException e){

             e.printStackTrace();

             request.setAttribute("message", "上传文件的总大小超出限制");

             request.getRequestDispatcher("/uploadSong.jsp").forward(request, response);

             return;

         }

         catch (FileUploadException e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         } //遍历表单项集合

     }

     //处理上传文件的函数

     private void processUploadField(FileItem fileItem) {

         //得到上传文件的名字

         String filename = fileItem.getName();

         //得到文件输入流

         try {

             InputStream is = fileItem.getInputStream();

             //将文件保存在服务器上

             String directoryRealPath =this.getServletContext().getRealPath("/WEB-INF/upload");//创建的路径

             File storeDirectory = new File(directoryRealPath);

             if(!storeDirectory.exists()){

                 storeDirectory.mkdir(); //创建一个指定目录

             }

             //处理文件名

             //filename =filename.substring(filename.lastIndexOf(File.separator)+1);

             if(filename!=null){

                 filename=FilenameUtils.getName(filename);

             }

             //不让文件名重复

             filename=UUID.randomUUID()+"_"+filename;

             //打散目录

             String childDirectory = makChildDirectory(storeDirectory,filename);

             //构建一个完整的文件路径

             /*File file =new File(storeDirectory,childDirectory+File.separator+filename);

             //创建一个写的流，将图片写入路径

             FileOutputStream fos = new FileOutputStream(file);

             int len=0;

             byte [] buf = new byte[1024];

             while((len=is.read(buf))!=-1){

                 fos.write(buf,0,len);

             }

             fos.close();

             is.close();*/

             //用工具类实现文件上传操作

             fileItem.write(new File(storeDirectory,childDirectory+File.separator+filename));

             fileItem.delete();//删除临时文件

         } catch (Exception e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

     }

     //打散目录

     private String makChildDirectory(File storeDirectory, String filename) {

         int hashcode = filename.hashCode();

         //把hashcode转换成16进制

         String code = Integer.toHexString(hashcode);

         String childDirectory = code.charAt(0)+File.separator+code.charAt(1);

         File file = new File(storeDirectory,childDirectory);

         if(!file.exists()){

             file.mkdirs();

         }

         return childDirectory;

     }

     //处理普通表单的函数

     private void processFormField(FileItem fileItem) {

         //解决文件名字乱码问题

         try {

             String fieldName = fileItem.getFieldName(); //获取字段名

             //String fieldValue = fileItem.getString();   //获取值

             String fieldValue  = fileItem.getString("utf-8");

         } catch (UnsupportedEncodingException e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

     }

     public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

         doGet(request, response);

     }

 }