返回语句后的java意外输出

Question

我有以下代码：

public class MainClass {

    static int someStaticVariable = 0;

    public static void main(String[] args) {

        MainClass obj = new MainClass();
        obj.someInstanceMethod();
        System.out.println("Count in main method " + someStaticVariable);
    }

    public int someInstanceMethod() {

        String someString = "line1\nline2\n";

        System.out.println("Count in someInstanceMethod method "
                    + (someStaticVariable + someString.split("\r\n|\r|\n").length));

        return (someStaticVariable + someString.split("\r\n|\r|\n").length);

    }
}

问题：为什么输出是：

Count in someInstanceMethod method 2
Count in main method 0

而非

Count in someInstanceMethod method 2
Count in main method 2

以及为什么它在someInstanceMethod中打印到Count in someInstanceMethod method 2，然后返回0，然后在main方法中打印0

Answer 1

您没有为someStaticVariable分配任何内容；您忽略了someInstanceMethod的返回。试一试

someStaticVariable = obj.someInstanceMethod();

或者，您可以在方法本身中指定它

someStaticVariable += someString.split("\r\n|\r|\n").length;
return (someStaticVariable + someString.split("\r\n|\r|\n").length);

Answer 2

问题是您没有篡改someStaticVariable

您只需打印出someStaticVariable（即0）和someString.split("\r\n|\r|\n").length之和

您需要做的是分配：

someStaticVariable = obj.someInstanceMethod();