Method main

src/class026/Code03_Comparator.java:33–94

(String[] args)

	}

	public static void main(String[] args) {
		Employee s1 = new Employee(2, 27);
		Employee s2 = new Employee(1, 60);
		Employee s3 = new Employee(4, 19);
		Employee s4 = new Employee(3, 23);
		Employee s5 = new Employee(1, 35);
		Employee s6 = new Employee(3, 55);
		Employee[] arr = { s1, s2, s3, s4, s5, s6 };
		Arrays.sort(arr, new EmployeeComparator());
		for (Employee e : arr) {
			System.out.println(e.company + " , " + e.age);
		}

		System.out.println("=====");

		Arrays.sort(arr, (a, b) -> b.age - a.age);
		for (Employee e : arr) {
			System.out.println(e.company + " , " + e.age);
		}

		System.out.println("=====");
		// 所有员工，先按照谁的公司编号小，谁在前；如果公司编号一样，谁年龄小谁在前
		Arrays.sort(arr, (a, b) -> a.company != b.company ? (a.company - b.company) : (a.age - b.age));
		for (Employee e : arr) {
			System.out.println(e.company + " , " + e.age);
		}

		TreeSet<Employee> treeSet1 = new TreeSet<>(new EmployeeComparator());
		for (Employee e : arr) {
			treeSet1.add(e);
		}
		System.out.println(treeSet1.size());

		// 会去重
		treeSet1.add(new Employee(2, 27));
		System.out.println(treeSet1.size());

		System.out.println("===");

		// 如果不想去重，就需要增加更多的比较
		// 比如对象的内存地址、或者如果对象有数组下标之类的独特信息
		TreeSet<Employee> treeSet2 = new TreeSet<>((a, b) -> a.company != b.company ? (a.company - b.company)
				: a.age != b.age ? (a.age - b.age) : a.toString().compareTo(b.toString()));
		for (Employee e : arr) {
			treeSet2.add(e);
		}
		System.out.println(treeSet2.size());

		// 不会去重
		treeSet2.add(new Employee(2, 27));
		System.out.println(treeSet2.size());

		System.out.println("===");

		// PriorityQueue不会去重，不再展示了

		// 字典序
		String str1 = "abcde";