Java计算文本MD5加密值的方法示例

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class GetMd5 {
  public static void main(String[] args) {
    String a="123";
  System.out.println(getMd5(a));
  }
  /**
   * 获取文本字段的MD5值
   * @param txt
   * @return
   */
  public static String getMd5(String txt){
    String rs = "";
    String[] hexDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8","9", "a", "b", "c", "d", "e", "f" };
    try {
      MessageDigest messageDigest = MessageDigest.getInstance("MD5");
      byte[] b = messageDigest.digest(txt.getBytes());
      StringBuffer resultSb = new StringBuffer();
      for (int i = 0; i < b.length; i++) {
        int n = b[i];
        if (n < 0)
          n = 256 + n;
        int d1 = n / 16;
        int d2 = n % 16;
        resultSb.append(hexDigits[d1] + hexDigits[d2]);
      }
      rs = resultSb.toString();
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    }
    return rs;
  }
}