如何避免在Arraylist中嵌套循环以在Java中检索数据？

Question

我们有POJO课程的员工和项目。虽然大师级具有项目的对象和项目列表的对象。我们还在主类中创建了主类中的阵列列表，其中分配和检索数据。

员工PO​​JO

public class Employee {
    Integer empID;
    String name;
    String desig;

    public Employee(Integer empID, String name, String desig) {
        this.empID = empID;
        this.name = name;
        this.desig = desig;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "empID=" + empID +
                ", name='" + name + '\'' +
                ", desig='" + desig + '\'' +
                '}';
    }

    public Integer getEmpID() {
        return empID;
    }

    public void setEmpID(Integer empID) {
        this.empID = empID;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDesig() {
        return desig;
    }

    public void setDesig(String desig) {
        this.desig = desig;
    }
}

Project Pojo

public class Project {

    Integer projID;
    String projName;
    String location;
    Integer empID;

    public Project(Integer projID, String projName, String location, Integer empID) {
        this.projID = projID;
        this.projName = projName;
        this.location = location;
        this.empID = empID;
    }

    public Integer getProjID() {
        return projID;
    }

    public void setProjID(Integer projID) {
        this.projID = projID;
    }

    public String getProjName() {
        return projName;
    }

    public void setProjName(String projName) {
        this.projName = projName;
    }

    public String getLocation() {
        return location;
    }

    public void setLocation(String location) {
        this.location = location;
    }

    public Integer getEmpID() {
        return empID;
    }

    public void setEmpID(Integer empID) {
        this.empID = empID;
    }

    @Override
    public String toString() {
        return "Project{" +
                "projID=" + projID +
                ", projName='" + projName + '\'' +
                ", location='" + location + '\'' +
                ", empID=" + empID +
                '}';
    }
}

Master Pojo

public class Master {
    Employee employee;
    ArrayList<Project> projects;

    public Employee getEmployee() {
        return employee;
    }

    public void setEmployee(Employee employee) {
        this.employee = employee;
    }

    public ArrayList<Project> getProjects() {
        return projects;
    }

    public void setProjects(ArrayList<Project> projects) {
        this.projects = projects;
    }

    public Master(Employee employee, ArrayList<Project> projects) {
        this.employee = employee;
        this.projects = projects;
    }

    @Override
    public String toString() {
        return "Master{" +
                "employee=" + employee +
                ", projects=" + projects +
                '}';
    }

}

Main类

public class Main {
    public static void main(String[] args) {

        ArrayList<Master> masters = new ArrayList<>();

        addData(masters);

        fetchData(masters);

    }

    private static void addData(ArrayList<Master> masters) {

        // WE ARE INITIALIZING MASTERS IN THIS BLOCK WITH DATA FROM DB
    }


    private static void fetchData(ArrayList<Master> masters) {

        for (int i = 0; i < masters.size(); i++) {
            System.out.println("Employee "+(i+1)+" "+masters.get(i).getEmployee().getEmpID()+" "
            +masters.get(i).getEmployee().getName()+" "+masters.get(i).getEmployee().getDesig());

            for (int j = 0; j < masters.get(i).getProjects().size(); j++) {
                System.out.println("Projects "+masters.get(i).getProjects().get(j).getProjID()+" "
                +masters.get(i).getProjects().get(j).getProjName()+" "+masters.get(i).getProjects().get(j).getLocation()
                +" "+masters.get(i).getProjects().get(j).getEmpID());

            }
        }
    }
}

如何在主类中的FetchData（）方法中删除此嵌套以提高时间复杂性？