java調用自帶的計算器

ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine SE = manager.getEngineByName("js");
String number="((15+5)*(12/3))*5+1+1.1*0.1";
try {
    String ans = SE.eval(number).toString();
    System.out.println(ans);
}
catch (ScriptException e) {
    e.printStackTrace();
}