java 下载示例

 1 package com.charmyin.cmstudio.common.utils;

 2 

 3 import java.io.BufferedInputStream;

 4 import java.io.BufferedOutputStream;

 5 import java.io.File;

 6 import java.io.FileInputStream;

 7 import java.io.IOException;

 8 import java.io.InputStream;

 9 import java.io.OutputStream;

10 

11 import javax.servlet.http.HttpServletResponse;

12 

13 public class DownLoadExcelUtil {

14 

15     

16     public static void downLoadFile(String filePath, HttpServletResponse response, String fileName, String fileType)

17             throws Exception {

18             File file = new File(filePath);  //根据文件路径获得File文件

19             //设置文件类型(这样设置就不止是下Excel文件了，一举多得)

20             if("pdf".equals(fileType)){

21                response.setContentType("application/pdf;charset=GBK");

22             }else if("xls".equals(fileType)){

23                response.setContentType("application/msexcel;charset=GBK");

24             }else if("doc".equals(fileType)){

25                response.setContentType("application/msword;charset=GBK");

26             }

27             //文件名

28             response.setHeader("Content-Disposition", "attachment;filename=\""

29                 + new String(fileName.getBytes(), "ISO8859-1") + "\"");

30             response.setContentLength((int) file.length());

31             byte[] buffer = new byte[4096];// 缓冲区

32             BufferedOutputStream output = null;

33             BufferedInputStream input = null;

34             try {

35               output = new BufferedOutputStream(response.getOutputStream());

36               input = new BufferedInputStream(new FileInputStream(file));

37               int n = -1;

38               //遍历，开始下载

39               while ((n = input.read(buffer, 0, 4096)) > -1) {

40                  output.write(buffer, 0, n);

41               }

42               output.flush();   //不可少

43               response.flushBuffer();//不可少

44             } catch (Exception e) {

45               //异常自己捕捉       

46             } finally {

47                //关闭流，不可少

48                if (input != null)

49                     input.close();

50                if (output != null)

51                     output.close();

52             }

53         }

54     

55      public static HttpServletResponse download(String path, HttpServletResponse response) {

56             try {

57                 // path是指欲下载的文件的路径。

58                 File file = new File(path);

59                 // 取得文件名。

60                 String filename = file.getName();

61                 // 取得文件的后缀名。

62                 String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();

63 

64                 // 以流的形式下载文件。

65                 InputStream fis = new BufferedInputStream(new FileInputStream(path));

66                 byte[] buffer = new byte[fis.available()];

67                 fis.read(buffer);

68                 fis.close();

69                 // 清空response

70                 response.reset();

71                 // 设置response的Header

72                 response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));

73                 response.addHeader("Content-Length", "" + file.length());

74                 OutputStream toClient = new BufferedOutputStream(response.getOutputStream());

75                 response.setContentType("application/octet-stream");

76                 toClient.write(buffer);

77                 toClient.flush();

78                 toClient.close();

79             } catch (IOException ex) {

80                 ex.printStackTrace();

81             }

82             return response;

83         }

84 }