文件上传

  1 package servlet;
  2 
  3 import org.apache.tomcat.util.http.fileupload.*;
  4 import org.apache.tomcat.util.http.fileupload.disk.DiskFileItemFactory;
  5 import org.apache.tomcat.util.http.fileupload.servlet.ServletFileUpload;
  6 import org.apache.tomcat.util.http.fileupload.servlet.ServletRequestContext;
  7 
  8 import javax.servlet.ServletException;
  9 import javax.servlet.annotation.WebServlet;
 10 import javax.servlet.http.HttpServlet;
 11 import javax.servlet.http.HttpServletRequest;
 12 import javax.servlet.http.HttpServletResponse;
 13 import java.io.File;
 14 import java.io.FileOutputStream;
 15 import java.io.IOException;
 16 import java.io.InputStream;
 17 import java.util.Calendar;
 18 import java.util.Iterator;
 19 import java.util.List;
 20 import java.util.UUID;
 21 
 22 /**
 23  * 处理文件上传 
 24  *
 25  **/
 26 @WebServlet("/UploadServlet")
 27 public class UploadServlet extends HttpServlet {
 28     @Override
 29     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 30         //设置文件上传基本路径
 31         String savePath = this.getServletContext().getRealPath("/WEB-INF/uploadFiles");
 32         //设置临时文件路径
 33         String tempPath = this.getServletContext().getRealPath("/WEB-INF/tempFiles");
 34         File tempFile = new File(tempPath);
 35         if (!tempFile.exists()) {
 36             tempFile.mkdir();
 37         }
 38 
 39         //定义异常消息
 40         String errorMessage = "";
 41         //创建file items工厂
 42         DiskFileItemFactory factory = new DiskFileItemFactory();
 43         //设置缓冲区大小
 44         factory.setSizeThreshold(1024 * 100);
 45         //设置临时文件路径
 46         factory.setRepository(tempFile);
 47         //创建文件上传处理器
 48         ServletFileUpload upload = new ServletFileUpload(factory);
 49         //监听文件上传进度
 50         ProgressListener progressListener = new ProgressListener() {
 51             public void update(long pBytesRead, long pContentLength, int pItems) {
 52                 System.out.println("正在读取文件： " + pItems);
 53                 if (pContentLength == -1) {
 54                     System.out.println("已读取： " + pBytesRead + " 剩余0");
 55                 } else {
 56                     System.out.println("文件总大小：" + pContentLength + " 已读取：" + pBytesRead);
 57                 }
 58             }
 59         };
 60         upload.setProgressListener(progressListener);
 61 
 62         //解决上传文件名的中文乱码
 63         upload.setHeaderEncoding("UTF-8");
 64         //判断提交上来的数据是否是上传表单的数据
 65         if (!ServletFileUpload.isMultipartContent(request)) {
 66             //按照传统方式获取数据
 67             return;
 68         }
 69 
 70         //设置上传单个文件的大小的最大值，目前是设置为1024*1024字节，也就是1MB
 71         upload.setFileSizeMax(1024 * 1024);
 72         //设置上传文件总量的最大值，最大值=同时上传的多个文件的大小的最大值的和，目前设置为10MB
 73         upload.setSizeMax(1024 * 1024 * 10);
 74 
 75         try {
 76             //使用ServletFileUpload解析器解析上传数据，解析结果返回的是一个List<FileItem>集合，每一个FileItem对应一个Form表单的输入项
 77             List<FileItem> items = upload.parseRequest(new ServletRequestContext(request));
 78             Iterator<FileItem> iterator = items.iterator();
 79             while (iterator.hasNext()) {
 80                 FileItem item = iterator.next();
 81 
 82                 //判断jsp提交过来的是不是文件
 83                 if (item.isFormField()) {
 84                     errorMessage = "请提交文件！";
 85                     break;
 86                 } else {
 87                     //文件名
 88                     String fileName = item.getName();
 89 
 90                     if (fileName == null || fileName.trim() == "") {
 91                         System.out.println("文件名为空！");
 92                     }
 93                     //处理不同浏览器提交的文件名带路径问题
 94                     fileName = fileName.substring(fileName.lastIndexOf("\\") + 1);
 95                     //文件扩展名
 96                     String fileExtension = fileName.substring(fileName.lastIndexOf(".") + 1);
 97                     //判断扩展名是否合法
 98                     if (!validExtension(fileExtension)) {
 99                         errorMessage = "上传文件非法！";
100                         item.delete();
101                         break;
102                     }
103                     //获得文件输入流
104                     InputStream in = item.getInputStream();
105                     //得到文件保存路径
106                     String realFilePath = createRealFilePath(savePath, fileName);
107                     System.out.println(realFilePath);
108                     //创建文件输出流
109                     FileOutputStream out = new FileOutputStream(realFilePath);
110                     //创建缓冲区
111                     byte buffer[] = new byte[1024];
112                     int len = 0;
113                     while ((len = in.read(buffer)) > 0) {
114                         //写文件
115                         out.write(buffer, 0, len);
116                     }
117                     //关闭输入流
118                     in.close();
119                     //关闭输出流
120                     out.close();
121                     //删除临时文件 TODO
122                     item.delete();
123                     //将上传文件信息保存到附件表中 TODO
124                 }
125 
126             }
127 
128         } catch (FileUploadBase.FileSizeLimitExceededException e) {
129             e.printStackTrace();
130             request.setAttribute("errorMessage", "单个文件超出最大值！！！");
131             request.getRequestDispatcher("jsp/demo03.jsp").forward(request, response);
132             return;
133         } catch (FileUploadBase.SizeLimitExceededException e) {
134             e.printStackTrace();
135             request.setAttribute("errorMessage", "上传文件的总的大小超出限制的最大值！！！");
136             request.getRequestDispatcher("jsp/demo03.jsp").forward(request, response);
137             return;
138         } catch (FileUploadException e) {
139             e.printStackTrace();
140             request.setAttribute("errorMessage", "文件上传失败！！！");
141             request.getRequestDispatcher("jsp/demo03.jsp").forward(request, response);
142             return;
143         }
144 
145         request.setAttribute("errorMessage", errorMessage);
146         request.getRequestDispatcher("jsp/demo03.jsp").forward(request, response);
147 
148 
149     }
150 
151     @Override
152     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
153         doGet(request, response);
154     }
155 
156     private boolean validExtension(String fileExtension) {
157         String[] exts = {"jpg", "txt", "doc", "pdf"};
158         for (int i = 0; i < exts.length; i++) {
159             if (fileExtension.equals(exts[i])) {
160                 return true;
161             }
162 
163         }
164 
165         return false;
166     }
167 
168 //    private String createFileName(String fileName) {
169 //        return UUID.randomUUID().toString() + "_" + fileName;
170 //    }
171 
172     /**
173      * 根据基本路径和文件名称生成真实文件路径，基本路径\\年\\月\\fileName
174      *
175      */
176     private String createRealFilePath(String basePath, String fileName) {
177         Calendar today = Calendar.getInstance();
178         String year = String.valueOf(today.get(Calendar.YEAR));
179         String month = String.valueOf(today.get(Calendar.MONTH) + 1);
180 
181 
182         String upPath = basePath + File.separator + year + File.separator + month + File.separator;
183         File uploadFolder = new File(upPath);
184         if (!uploadFolder.exists()) {
185             uploadFolder.mkdirs();
186         }
187 
188         String realFilePath = upPath + fileName;
189 
190         return realFilePath;
191     }
192 }