utils.java

针对网络跑步爱好者作为用户而开发的

package com.briup.run.common.util.ip;

import java.io.UnsupportedEncodingException;
import java.util.StringTokenizer;

public class Utils {
	/** IP��ݿ��ļ� */
	public static String IP_FILE=(Utils.class.getResource("")+"ip.dat").substring(6);
	//	 string buffer
    private static StringBuilder sb = new StringBuilder();
	
	 /**
     * @param ip ip���ֽ�������ʽ
     * @return �ַ���ʽ��ip
     */
    public static String getIpStringFromBytes(byte[] ip) {
	    sb.delete(0, sb.length());
    	sb.append(ip[0] & 0xFF);
    	sb.append('.');   	
    	sb.append(ip[1] & 0xFF);
    	sb.append('.');   	
    	sb.append(ip[2] & 0xFF);
    	sb.append('.');   	
    	sb.append(ip[3] & 0xFF);
    	return sb.toString();
    }
    
    /**
     * ��ip���ַ���ʽ�õ��ֽ�������ʽ
     * @param ip �ַ���ʽ��ip
     * @return �ֽ�������ʽ��ip
     */
    public static byte[] getIpByteArrayFromString(String ip) {
        byte[] ret = new byte[4];
        StringTokenizer st = new StringTokenizer(ip, ".");
        try {
            ret[0] = (byte)(Integer.parseInt(st.nextToken()) & 0xFF);
            ret[1] = (byte)(Integer.parseInt(st.nextToken()) & 0xFF);
            ret[2] = (byte)(Integer.parseInt(st.nextToken()) & 0xFF);
            ret[3] = (byte)(Integer.parseInt(st.nextToken()) & 0xFF);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return ret;
    }
    /**
     * ��ԭʼ�ַ���б���ת�������ʧ�ܣ�����ԭʼ���ַ�
     * @param s ԭʼ�ַ�
     * @param srcEncoding Դ���뷽ʽ
     * @param destEncoding Ŀ����뷽ʽ
     * @return ת���������ַ�ʧ�ܷ���ԭʼ�ַ�
     */
    public static String getString(String s, String srcEncoding, String destEncoding) {
        try {
            return new String(s.getBytes(srcEncoding), destEncoding);
        } catch (UnsupportedEncodingException e) {
            return s;
        }
    }
    /**
     * ���ij�ֱ��뷽ʽ���ֽ�����ת�����ַ�
     * @param b �ֽ�����
     * @param offset Ҫת������ʼλ��
     * @param len Ҫת���ij���
     * @param encoding ���뷽ʽ
     * @return ���encoding��֧�֣�����һ��ȱʡ������ַ�
     */
    public static String getString(byte[] b, int offset, int len, String encoding) {
        try {
            return new String(b, offset, len, encoding);
        } catch (UnsupportedEncodingException e) {
            return new String(b, offset, len);
        }
    }
}