//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();

    }

}