用java写查子部门的递归算法

以下是用Java编写的查找子部门的递归算法示例：

public class Department {
    private String name;
    private List<Department> subDepartments;

    public Department(String name) {
        this.name = name;
        this.subDepartments = new ArrayList<>();
    }

    public String getName() {
        return name;
    }

    public List<Department> getSubDepartments() {
        return subDepartments;
    }

    public void addSubDepartment(Department department) {
        subDepartments.add(department);
    }

    public void removeSubDepartment(Department department) {
        subDepartments.remove(department);
    }
}

public class DepartmentUtils {

    public static List<Department> findSubDepartments(Department department) {
        List<Department> subDepartments = new ArrayList<>();
        if (department != null) {
            subDepartments.add(department);
            for (Department subDepartment : department.getSubDepartments()) {
                subDepartments.addAll(findSubDepartments(subDepartment));
            }
        }
        return subDepartments;
    }
}

// 示例用法
Department rootDepartment = new Department("root");
Department department1 = new Department("department1");
Department department2 = new Department("department2");
Department department3 = new Department("department3");
Department department4 = new Department("department4");
Department department5 = new Department("department5");

rootDepartment.addSubDepartment(department1);
rootDepartment.addSubDepartment(department2);
department1.addSubDepartment(department3);
department1.addSubDepartment(department4);
department3.addSubDepartment(department5);

List<Department> subDepartments = DepartmentUtils.findSubDepartments(rootDepartment);
for (Department subDepartment : subDepartments) {
    System.out.println(subDepartment.getName());
}

此代码将输出以下内容：

root
department1
department3
department5
department4
department2

在上面的示例中，我们使用了一个Department类来表示部门，并用一个List来存储子部门。然后，我们定义了一个DepartmentUtils类，其中包含了一个findSubDepartments()方法，它是一个递归方法，用于查找给定部门的所有子部门。该方法接受一个Department对象作为参数，并返回一个List，其中包含了该部门及其所有子部门。

在示例用法中，我们创建了一个根部门，并为其添加了几个子部门。然后，我们调用了findSubDepartments()方法，将根部门作为参数传递给它，并将返回的所有子部门打印出来。