开发中遇到对视频文件的md5的检测判断，经常会发生OOM。
解决办法如下：
public class MD5Util {
public static String getMd5ByFile(File file) {
InputStream fis;
byte[] buffer = new byte[2048];
int numRead = 0;
MessageDigest md5;
try {
fis = new FileInputStream(file);
md5 = MessageDigest.getInstance("MD5");
while ((numRead = fis.read(buffer)) > 0) {
md5.update(buffer, 0, numRead);
}
fis.close();
return md5ToString(md5.digest());
} catch (Exception e) {
System.out.println("error");
return null;
}
}
public static String md5ToString(byte[] md5Bytes) {
StringBuffer hexValue = new StringBuffer();
for (int i = 0; i < md5Bytes.length; i++) {
int val = ((int) md5Bytes[i]) & 0xff;
if (val < 16) {
hexValue.append("0");
}
hexValue.append(Integer.toHexString(val));
}
return hexValue.toString();
}
}
