1 class FileUtils
2 {
3 //文件目录下文件总数目
4 public static int fileNumber(File dir)
5 {
6 int filenumber = 0;
7 if(dir.exists())
8 {
9 for(File file:dir.listFiles())
10 {
11 if(file.isDirectory())
12 {
13 filenumber = filenumber+fileNumber(file);
14 }
15 else
16 {
17 filenumber++;
18 }
19 }
20 }
21 return filenumber;
22 }
23
24 //判断文件是否为图片
25 public static boolean isImage(File imgFilePath)
26 {
27 try
28 {
29 FileInputStream imgfis = new FileInputStream(imgFilePath);
30 byte []imgbyte = new byte[imgfis.available()];
31 if((imgfis.read(imgbyte))!=-1)
32 {
33 if(imgbyte[0] == (byte) 'G' && imgbyte[1] == (byte) 'I' && imgbyte[2] == (byte) 'F')
34 {
35 return true;
36 }
37 else if(imgbyte[1] == (byte) 'P' && imgbyte[2] == (byte) 'N' && imgbyte[3] == (byte) 'G')
38 {
39 return true;
40 }
41 else if(imgbyte[6] == (byte) 'J' && imgbyte[7] == (byte) 'F' && imgbyte[8] == (byte) 'I'&& imgbyte[9] == (byte) 'F')
42 {
43 return true;
44 }
45 else
46 {
47 return false;
48 }
49 }
50 }catch(Exception e)
51 {
52 System.out.println(e.toString());
53 return false;
54 }
55 return false;
56 }
57
58
59 //返回该目录下所有文件的文件数组
60 public static File[] listAllDirectory(File dir)
61 {
62 if(dir!=null&&dir.exists())
63 {
64 File []finalfile = new File[fileNumber(dir)];
65 int markfile =0;
66 int fileln=0;
67 File files[] = dir.listFiles();
68 for(int i=0;i<files.length;i++)
69 {
70 if(files[i].isDirectory())
71 {
72 listAllDirectory(files[i]);
73 }
74 else
75 {
76 finalfile[markfile++]=files[i];
77 }
78 }
79 return finalfile;
80 }
81 else
82 {
83 return null;
84 }
85 }
86
87
88 //复制文件（用文件通道）
89 public static void copyFile(File oldFileAbsolutePath,File newFilePath)
90 {
91 File newFileAbsolutePath = new File(newFilePath,oldFileAbsolutePath.getName());
92 FileInputStream fi = null;
93 FileOutputStream fo = null;
94 FileChannel in = null;
95 FileChannel out = null;
96 try {
97 fi = new FileInputStream(oldFileAbsolutePath);
98 fo = new FileOutputStream(newFileAbsolutePath);
99 in = fi.getChannel();
100 out = fo.getChannel();
101 in.transferTo(0, in.size(), out);
102 } catch (IOException e)
103 {
104 e.printStackTrace();
105 }
106 finally
107 {
108 try
109 {
110 fi.close();
111 in.close();
112 fo.close();
113 out.close();
114 } catch (IOException e)
115 {
116 e.printStackTrace();
117 }
118 }
119 }
120 }
