String str = "00300028.客户咨询.020201.业务/市场营";
       int start = str.indexOf("客户咨询");
       str = str.substring(start,(start+4));
       System.out.println(str);

String str = "00300028.客户咨询.020201.业务/市场营";
       String[] arr = str.split("\\.");
       String newStr = "";
       for(int i=0;i<arr.length;i++){
           if(arr[i].equals("客户咨询")){
               newStr = arr[i];
               break;
           }
       }System.out.println(newStr);

System.out.println("00300028.客户咨询.020201.业务/市场营".replaceAll("^.*?\\.([\u4e00-\u9fa5]*).*$","$1"));

import java.util.regex.*;

public class Change
{
    public static void main(String[] args)
    {
        Pattern p=Pattern.compile(".*\\.(.*)\\..*\\..*");
        Matcher m=p.matcher("00300028.客户咨询.020201.业务/市场营 ");
        while(m.find())
        {
            System.out.println(m.group(1));
        }
    }
}