java 调用js 方法库进行简单的数学表达式的运算

@Testpublic void ttt() throws Exception {     String expr = "a==a";//"1>2 "

    boolean ss=ruleCal(expr);    System.out.println(ss);}

private Boolean ruleCal(String rule){    ScriptEngineManager manager = new ScriptEngineManager();    ScriptEngine engine = manager.getEngineByName("js");    Object result=null;    try {        result = engine.eval(rule);    } catch (ScriptException e) {        e.printStackTrace();    }    return Boolean.valueOf(String.valueOf(result));}