java优先队列，equals方法

优先队列的申明：

 Queue<Student> queue = new PriorityQueue<>();

要使得优先队列的排序起作用，就要让这个student实现Comparable中的compareTo方法

 @Override
    public int compareTo(Object o) {
        Student another = (Student) o;
        Integer anotherAge = another.age;
        if (this.age < anotherAge) {
            return -1;
        } else if (this.age == anotherAge) {
            return 0;
        }
        return 1;
    }

我在这里是按年龄排序，年龄小的返回-1，也就是正常情况下，这样优先队列里每次取出的就是年龄最小的那个student

 

此外关于重写equals问题

例如

@Override
    public boolean equals(Object obj) {
        Student another = (Student) obj;
        if (another.name.equals(this.name)) {
            return true;
        }
        return false;
    }

  Student student1 = new Student("1", 20, "徐康");
  Student student2 = new Student("2", 21, "徐康");

调用student1.equals(student2)返回true

Stack<Student> students=new Stack<>();
students.add(student1);
System.out.println(students.contains(student2));

List<Student> list=new ArrayList<>();
list.add(student1);
System.out.println(list.contains(student2));

两个都输出true