map中的值替换掉字符串中的变量（含运算）

import java.util.HashMap;
import java.util.Map;

import org.apache.commons.lang.text.StrSubstitutor;

import bsh.Interpreter;

public class Test {

/**
* @param args
*/
public static void main(String[] args) {
Test t = new Test();
Map map = new HashMap();
map.put("N1", new Integer(1));
map.put("N2", new Integer(2));
map.put("N3", new Integer(3));
map.put("N4", new Integer(4));
map.put("N5", new Integer(22));
map.put("N6", new Integer(6));
String str = "你好$${${N5}+${N6}-${N4}}";
StrSubstitutor strSubstitutor = new StrSubstitutor(map);
String result = t.operateVariable(strSubstitutor.replace(str),map);
System.out.print(result);
}

public String operateVariable(String str ,Map map){
String result = "";
int begin = 0;
int end = 0;
int count = 0;
String temp = "";
for(int i=0;i<str.length();i++){
      if(str.charAt(i)=='$'){
      begin = i+2;
      result += str.substring(end, i);
      }
      if(str.charAt(i)=='}'){
      end = i+1;
      temp = str.substring(begin, i);
      Interpreter  ii = new Interpreter();
      try{
      count = ((Integer)ii.eval(temp)).intValue();
      }catch(Exception e){
      e.printStackTrace();
      }
      result += count;
      }
      if(i==str.length()-1){
      result += str.substring(end, i+1);
      }
}
return result;
}
}