需要在java中打印如下格式的排序地图值

Question

public class SortData {

    public static void main(String[] args) {
        List<Employee> employees = Arrays.asList(
                      new Employee("102", "300", "100", "200"),
                      new Employee("101", "200", "80", "120"),
                      new Employee("102", "100", "50", "50"), 
                      new Employee("103", "300", "100", "200"),
                      new Employee("101", "200", "80", "120"),
                      new Employee("101", "100", "50", "50"));

        
        Map<String, Map<String, List<Employee>>> map = employees.stream()
                  .collect(Collectors.groupingBy(Employee::getEmpNo, 
    Collectors.groupingBy(Employee::getEmpSal)));
        
        System.out.println(map);
    }

}



class Employee {

    private String empNo;
    private String empSal;
    private String empHra;
    private String empPf;

    // getter
    // setter

  }

{101={100=[Employee(empNo=101, empSal=100, empHra=50, empPf=50)], 200=[Employee(empNo=101, 
  empSal=200, empHra=80, empPf=120), Employee(empNo=101, empSal=200, empHra=80, empPf=120)]}, 
  102={100=[Employee(empNo=102, empSal=100, empHra=50, empPf=50)], 300=[Employee(empNo=102, 
  empSal=300, empHra=100, empPf=200)]}, 
  103={300=[Employee(empNo=103, empSal=300, empHra=100, empPf=200)]}}

1011005050
10120080120
10120080120
1021005050
102300100200
103300100200

有人能帮帮我吗。

Answer 1

首先，当前实现中的映射没有排序。

其次，对地图进行排序可能是多余的。似乎为了打印输入数据，只需要按empno和empsal对输入列表进行排序：

Comparator<Employee> sortByNoAndSal = Comparator
        .comparing(Employee::getEmpNo)
        .thenComparing(Employee::getEmpSal);

employees.sort(sortByNoAndSal);

最后，要打印/输出Employee的实例，应该实现特定方法（通过重写Employee::ToString或创建特定方法）。另外，需要注意的输出似乎缺少employee字段之间的分隔符。

// class PrintData
public static void printEmployee(Employee emp) {
    String delimiter = ""; // fix if necessary
    System.out.println(String.join(delimiter, emp.getNo(), emp.getSal(), emp.getHra(), emp.getPf()));
}

// invoke this method
employees.forEach(PrintData::printEmployee);