java - 从父类获取字符串到子类的概念？

Question

如何从父类获取字符串到子类？请检查我的代码并告诉我该怎么做？我想获取从父类到子类的字符串。

public class ExtendExamle {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        File file=new File("D:\\softs\\IEDriverServer_Win32_2.42.0\\IEDriverServer.exe");
        System.setProperty("webdriver.ie.driver", file.getAbsolutePath());
        WebDriver driver = new InternetExplorerDriver();
        driver.get("https://www.gmail.com");
    }

    public static class Test extends ExtendExample {

        public static void main(String[] args) {

        }

   }

}

Answer 1

当一个类扩展另一个类时，子类会自动继承任何可见变量(未标记为 private 或没有访问修饰符的变量)。

class ParentClass {
     protected String url = "www.stackoverflow.com";
}

class ChildClass extends ParentClass { //automatically inherits url
     public void run() {
          //im guessing this class is where you want to use url?
          System.out.println(url);
     }
}

//A class to start to program
class Main {
     public static void main(String[] args) {
          ChildClass child = new ChildClass();
          child.run();
     }
 }

ChildClass会自动从ParentClass继承String，允许您在ChildClass中使用url，无需额外工作。