将员工先按工资再按年龄升序排序，java

可以使用Java中的Comparator接口和Collections.sort()方法来实现员工先按工资再按年龄升序排序，以下是示例代码：

首先，定义一个Employee类，包含工资和年龄两个属性：

public class Employee {
    private double salary;
    private int age;

    public Employee(double salary, int age) {
        this.salary = salary;
        this.age = age;
    }

    public double getSalary() {
        return salary;
    }

    public int getAge() {
        return age;
    }
}

然后，定义一个EmployeeComparator类实现Comparator接口，实现compare方法：

import java.util.Comparator;

public class EmployeeComparator implements Comparator<Employee> {
    @Override
    public int compare(Employee e1, Employee e2) {
        // 先按工资升序排序
        if (e1.getSalary() < e2.getSalary()) {
            return -1;
        } else if (e1.getSalary() > e2.getSalary()) {
            return 1;
        } else {
            // 如果工资相同再按年龄升序排序
            if (e1.getAge() < e2.getAge()) {
                return -1;
            } else if (e1.getAge() > e2.getAge()) {
                return 1;
            } else {
                return 0;
            }
        }
    }
}

最后，在主程序中创建一个Employee列表，使用Collections.sort()方法和EmployeeComparator进行排序：

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<Employee> employees = new ArrayList<>();
        employees.add(new Employee(6000, 30));
        employees.add(new Employee(5000, 25));
        employees.add(new Employee(4000, 35));
        employees.add(new Employee(5000, 30));

        Collections.sort(employees, new EmployeeComparator());

        for (Employee e : employees) {
            System.out.println("Salary: " + e.getSalary() + ", Age: " + e.getAge());
        }
    }
}

运行结果为：

Salary: 4000.0, Age: 35
Salary: 5000.0, Age: 25
Salary: 5000.0, Age: 30
Salary: 6000.0, Age: 30