用Java写出客户清单，共计500份，每份公司客户包含客户ID、客户名称、客户职级以及客户工资这些信息， 客户经理想要按照一定的优先顺序调查每个公司客户的信用情况，优先顺有两个要求，1、职级越高越优先，从高到底分别是 A\B\C\D\E。2、职级相同时，工资越高越优先。 有什么办法可以快速得到这个排序之后的清单?请写一个主方法测试类，把排序后的信息展示到工作台上。

客户类：

public class Customer {
    private String id;
    private String name;
    private String level;
    private double salary;

    public Customer(String id, String name, String level, double salary) {
        this.id = id;
        this.name = name;
        this.level = level;
        this.salary = salary;
    }

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getLevel() {
        return level;
    }

    public double getSalary() {
        return salary;
    }

    @Override
    public String toString() {
        return "Customer{" +
                "id='" + id + '\'' +
                ", name='" + name + '\'' +
                ", level='" + level + '\'' +
                ", salary=" + salary +
                '}';
    }
}

排序类：

import java.util.*;

public class CustomerSorter {
    public static void sortByLevelAndSalary(List<Customer> customers) {
        Collections.sort(customers, new Comparator<Customer>() {
            @Override
            public int compare(Customer o1, Customer o2) {
                if (o1.getLevel().equals(o2.getLevel())) {
                    return Double.compare(o2.getSalary(), o1.getSalary());
                } else {
                    return levelToPriority(o2.getLevel()) - levelToPriority(o1.getLevel());
                }
            }
        });
    }

    private static int levelToPriority(String level) {
        switch (level) {
            case "A":
                return 5;
            case "B":
                return 4;
            case "C":
                return 3;
            case "D":
                return 2;
            case "E":
                return 1;
            default:
                return 0;
        }
    }
}

测试类：

import java.util.*;

public class Main {
    public static void main(String[] args) {
        List<Customer> customers = new ArrayList<>();
        for (int i = 0; i < 500; i++) {
            customers.add(new Customer("id" + i, "name" + i, "ABCDE".charAt((int) (Math.random() * 5)) + "", Math.random() * 10000));
        }
        CustomerSorter.sortByLevelAndSalary(customers);
        for (Customer customer : customers) {
            System.out.println(customer);
        }
    }
}