new String(byte[] bytes, int offset,int length)有关问题

public class dsf {    /**     * @param args     */    public static void main(String[] args) {        String re,restr="";        int tr=0,i;        String str="1001-1002-1003-1004-1005";        byte[] buf= str.getBytes();        for(i=0;i<buf.length;i++)        {            if(buf[i]=='-')            {                re=new String(buf,tr,i);                System.out.println(re+" "+tr+" "+i);                tr=i+1;            }        }    }}