使用流过滤器比较双精度值

Question

我需要您的帮助来确定我现在正在处理的代码有什么问题。

这个任务的规范是过滤从一个csv文件中获取的对象列表，只得到薪水最高的前10名员工。我正在尝试这些行：

List<Employee> listOfTop10HighestPaidMaleEmployee = new ArrayList<>(employeeList);
    List<Employee> filterSalary;

            filterSalary = listOfTop10HighestPaidMaleEmployee
                    .stream()
                    .sorted(
                            Comparator.comparingDouble(Employee::getSalary)
                    )
                    .limit(10)
                    .collect(Collectors.toList());

当我使用 for-each 循环对其进行测试时，它会打印出 10 个值，但没有正确过滤掉薪水部分。我得到这个输出：

Employee{id='261461', name='Lucila Isai Gray Silvestre', department='Software Development Team', 
gender=M, age=34, employment status=Permanent, salary=20079.75, years of service=9}
Employee{id='368487', name='Joey Quinn Uson Solivio', department='Marketing', gender=M, age=34, 
employment status=Not Permanent, salary=20200.25, years of service=3}
Employee{id='353810', name='Carter Jamie Pagsisihan Lingao', department='Marketing', gender=M, 
age=24, employment status=Permanent, salary=20444.25, years of service=4}
Employee{id='330680', name='Erick Colby Magan Formalouza', department='IT Services', gender=M, 
age=52, employment status=Permanent, salary=20887.0, years of service=14}
Employee{id='220888', name='Jack Cornelius Parker Guinto', department='IT Services', gender=M, 
age=32, employment status=Permanent, salary=20950.0, years of service=10}
Employee{id='215350', name='Eugenio Jermaine Quiblat Bonachita', department='Marketing', gender=M, 
age=45, employment status=Not Permanent, salary=21263.5, years of service=2}
Employee{id='257430', name='Malaya Kaitlyn Hakamada Gonz�lez', department='IT Services', gender=F, 
age=35, employment status=Not Permanent, salary=21362.0, years of service=2}
Employee{id='212292', name='Kendra Mercedes Lomondot Fernando', department='Marketing', gender=F, a 
age=41, employment status=Not Permanent, salary=21371.75, years of service=3}
Employee{id='348771', name='Kristofer Israel Dura Portugal', department='Human Resource', gender=M, 
age=49, employment status=Permanent, salary=21402.5, years of service=6}
Employee{id='353227', name='Maegan Jaden Mahiya Isidro', department='Human Resource', gender=F, 
age=59, employment status=Not Permanent, salary=21442.25, years of service=3}

在交叉检查结果和列表后，它会打印出工资范围为 20000-21,000 的列表。在原始名单中，薪水高达30,000。关于如何过滤列表以显示工资最高的 10 名员工的列表的任何提示？任何帮助将不胜感激。提前谢谢！

Answer 1

已解决：

添加了 .reversed() 行，

listOfTop10HighestPaidMaleEmployee = listOfTop10HighestPaidMaleEmployee
                        .stream() 
                   .sorted(Comparator.comparingDouble(Employee::getSalary).reversed())
                        .limit(10)
                        .collect(Collectors.toList());

这会按降序排列列表的最后 10 个。

这是一个完整的例子。为简洁起见，使用新的 Java 16 record 功能。

record Employee(String name , double salary) {}

List < Employee > employees =
        List.of(
                new Employee( "Alice" , 88 ) ,    // # 1
                new Employee( "Bob" , 52 ) ,      // # 3
                new Employee( "Carol" , 33 ) ,
                new Employee( "Dennis" , 22 ) ,
                new Employee( "Ellen" , 77 ) ,    // # 2
                new Employee( "Francis" , 17 )
        );

List < Employee > highestPaid =
        employees
                .stream()
                .sorted(
                        Comparator.comparingDouble( Employee :: salary ).reversed()
                )
                .limit( 3 )
                .collect( Collectors.toList() );  // Or just `.toList()` in Java 16+.

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

运行时。

highestPaid = [员工[name=Alice，薪水=88.0]，员工[name=Ellen，薪水=77.0]，员工[name=Bob，薪水=52.0]]