import java.util.*;class Student { private String name; private String phone; public Student(String name, String phone) { this.name = name; this.phone = phone;
} public String toString() {
return name + ":" + phone;
}
}public class Test4 { public static void main(String[] args) { Student st1 = new Student("John", "23214"); Student st2 = new Student("Alice", "4563"); List<Student> list = new ArrayList<Student>(); list.add(st1);
list.add(st2); for (int i = 0; i < list.size(); i++) System.out.println(list.get(i)); }}
} public String toString() {
return name + ":" + phone;
}
}public class Test4 { public static void main(String[] args) { Student st1 = new Student("John", "23214"); Student st2 = new Student("Alice", "4563"); List<Student> list = new ArrayList<Student>(); list.add(st1);
list.add(st2); for (int i = 0; i < list.size(); i++) System.out.println(list.get(i)); }}
System.out.println(list.get(i));
会调用到list.get(i).toString()方法
因为list中存放的是Student类型
也就是说会调用Student的toString方法
如果Student类不去覆盖toString()方法就会调用它的超类即Object类的toString方法