非静态方法不能从静态上下文中引用

Question

下面的代码出现在我正在尝试创建的包的主类中.它从名为Journey的帮助程序类引用对象和方法.在journeyCost星号标记的方法中调用方法时,我得到"非静态方法不能从静态上下文引用"错误.这使我感到困惑,因为我认为在第二行创建的Journey对象"thisJourney"构成了类的实例,因此意味着上下文不是静态的.谢谢,Seany.

public boolean journey(int date, int time, int busNumber, int journeyType){
        Journey thisJourney = new Journey(date, time, busNumber, journeyType);

        if (thisJourney.isInSequence(date, time) == false)
        {
            return false;            
        }
        else
        {
            Journey.updateCurrentCharges(date);

            thisJourney.costOfJourney = Journey.journeyCost(thisJourney);***** 
            Journey.dayCharge = Journey.dayCharge + thisJourney.costOfJourney;
            Journey.weekCharge = Journey.weekCharge + thisJourney.costOfJourney;
            Journey.monthCharge = Journey.monthCharge + thisJourney.costOfJourney;

            Balance = Balance - thisJourney.costOfJourney;
            jArray.add(thisJourney);
        }

    } 

Answer 1

该错误意味着您尝试以静态方式调用非静态方法,例如:

 Journey.journeyCost(thisJourney);

被journeyCost()宣布为静态？你的意思不是thisJourney.journeyCost()吗？

另外,您应该使用getter和setter来修改和访问您的成员变量,而不是:

Journey.dayCharge = ...

你应该有

Journey.setDayCharge(Journey.getDayCharge() + thisJourney.getCostOfJourney());

(setDayCharge和getDayCharge需要是静态在这种情况下)