Java WEB ----- 文件的上传

最近学到的web阶段的文件的上传，就想记录一下，帮助自己复习以及帮助大家学习,一般我都会把上传的文件存到服务器中的web-inf 下面，因为这样用户不会直接访问到，我们存到数据库的一般都是路径。这里没有演示数据库上传路径，气势上传路径很简单，只需要你把路径和文件名插入到数据库中的某个表就可以了，等你到时候想用找到文件的时候，就从数据库中查找路径就行了。废话不说，上代码（上传文件的servlet，前台界面只需要有一个类型为file的 input标签，如果想一次选上传多个，可以多写几个input或者在input标签内 增加multiple="multiple" 属性，就可以实现一个input中写入好几个文件）：

 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);
     }

 }