Java Sha1 加密算法

//下面四个import放在类名前面 包名后面
//import java.io.UnsupportedEncodingException;
//import java.security.MessageDigest;
//import java.security.NoSuchAlgorithmException;
//import java.util.Arrays;
 
public static String getSha1(String str){
    if (null == str || 0 == str.length()){
        return null;
    }
    char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
            'a', 'b', 'c', 'd', 'e', 'f'};
    try {
        MessageDigest mdTemp = MessageDigest.getInstance("SHA1");
        mdTemp.update(str.getBytes("UTF-8"));
         
        byte[] md = mdTemp.digest();
        int j = md.length;
        char[] buf = new char[j * 2];
        int k = 0;
        for (int i = 0; i < j; i++) {
            byte byte0 = md[i];
            buf[k++] = hexDigits[byte0 >>> 4 & 0xf];
            buf[k++] = hexDigits[byte0 & 0xf];
        }
        return new String(buf);
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    }
}