Java SHA 哈希算法实例［可直接用］

1. 用SHA-256算法，检验文件:
   使用 sha-256 哈希算法生成”c:\loging.log”文件的校验码。

import java.io.FileInputStream;
import java.security.MessageDigest;

public class SHACheckSumExample
{
    public static void main(String[] args)throws Exception
    {
        MessageDigest md = MessageDigest.getInstance("SHA-256");
        FileInputStream fis = new FileInputStream("c:\\loging.log");

        byte[] dataBytes = new byte[1024];

        int nread = 0;
        while ((nread = fis.read(dataBytes)) != -1) {
          md.update(dataBytes, 0, nread);
        };
        byte[] mdbytes = md.digest();

        //convert the byte to hex format method 1
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < mdbytes.length; i++) {
          sb.append(Integer.toString((mdbytes[i] & 0xff) + 0x100, 16).substring(1));
        }

        System.out.println("Hex format : " + sb.toString());

       //convert the byte to hex format method 2
        StringBuffer hexString = new StringBuffer();
        for (int i=0;i0xFF & mdbytes[i]));
        }

        System.out.println("Hex format : " + hexString.toString());
    }
}

Output:

Hex format : 21a57f2fe765e1ae4a8bf15d73fc1bf2a533f547f2343d12a499d9c0592044d4
Hex format : 21a57f2fe765e1ae4a8bf15d73fc1bf2a533f547f2343d12a499d9c0592044d4

2.用SHA-256算法对字符串加密:
使用哈希算法对字符串”123456”加密

import java.security.MessageDigest;

public class SHAHashingExample
{
    public static void main(String[] args)throws Exception
    {
        String password = "123456";

        MessageDigest md = MessageDigest.getInstance("SHA-256");
        md.update(password.getBytes());

        byte byteData[] = md.digest();

        //convert the byte to hex format method 1
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < byteData.length; i++) {
         sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1));
        }

        System.out.println("Hex format : " + sb.toString());

        //convert the byte to hex format method 2
        StringBuffer hexString = new StringBuffer();
        for (int i=0;i0xff & byteData[i]);
            if(hex.length()==1) hexString.append('0');
            hexString.append(hex);
        }
        System.out.println("Hex format : " + hexString.toString());
    }
}

Output：

Hex format : 8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92
Hex format : 8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92

参考url