1 package test;
2
3 import java.io.File;
4 import java.io.FileInputStream;
5 import java.math.BigInteger;
6 import java.security.MessageDigest;
7 import java.util.HashMap;
8 import java.util.Map;
9
10 public class FileDigest {
11 /**
12 * 获取单个文件的MD5值！
13 *
14 * @param file
15 * @return
16 */
17 public static String getFileMD5(File file) {
18 if (!file.isFile()) {
19 return null;
20 }
21 MessageDigest digest = null;
22 FileInputStream in = null;
23 byte buffer[] = new byte[1024];
24 int len;
25 try {
26 digest = MessageDigest.getInstance("MD5");
27 in = new FileInputStream(file);
28 while ((len = in.read(buffer, 0, 1024)) != -1) {
29 digest.update(buffer, 0, len);
30 }
31 in.close();
32 } catch (Exception e) {
33 e.printStackTrace();
34 return null;
35 }
36 BigInteger bigInt = new BigInteger(1, digest.digest());
37 return bigInt.toString(16);
38 }
39
40 /**
41 * 获取文件夹中文件的MD5值
42 *
43 * @param file
44 * @param listChild
45 * ;true递归子目录中的文件
46 * @return
47 */
48 public static Map<String, String> getDirMD5(File file, boolean listChild) {
49 if (!file.isDirectory()) {
50 return null;
51 }
52 // <filepath,md5>
53 Map<String, String> map = new HashMap<String, String>();
54 String md5;
55 File files[] = file.listFiles();
56 for (int i = 0; i < files.length; i++) {
57 File f = files[i];
58 if (f.isDirectory() && listChild) {
59 map.putAll(getDirMD5(f, listChild));
60 } else {
61 md5 = getFileMD5(f);
62 if (md5 != null) {
63 map.put(f.getPath(), md5);
64 }
65 }
66 }
67 return map;
68 }
69
70 public static void main(String[] args) {
71 File file1 = new File("H:/update/lib/111.txt");
72 File file2 = new File("H:/1111.txt");
73 System.out.println(getFileMD5(file1).equals(getFileMD5(file2)));
74 }
75
76 }
