java获取文件的md5值

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Test {

public static void main(String[] args) {
try {
File file = new File("F://test.txt");
FileInputStream fis = new FileInputStream(file);
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] buffer = new byte[1024];
int length = -1;
while ((length = fis.read(buffer, 0, 1024)) != -1) {
md.update(buffer, 0, length);
}
BigInteger bigInt = new BigInteger(1, md.digest());
System.out.println("文件md5值：" + bigInt.toString(16));
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

}