使用Java取出末级部门

假设我们有一个Department类，其中包含id和parentId属性，parentId为0表示该部门为顶级部门。

我们可以通过递归的方式，从顶级部门开始遍历整个部门树，找到所有末级部门：

public List<Department> getLeafDepartments(List<Department> departments, int parentId) {
    List<Department> result = new ArrayList<>();
    for (Department department : departments) {
        if (department.getParentId() == parentId) {
            List<Department> children = getLeafDepartments(departments, department.getId());
            if (children.isEmpty()) {
                result.add(department);
            } else {
                result.addAll(children);
            }
        }
    }
    return result;
}

我们可以将所有部门存储在一个列表中，然后调用该方法来获取所有末级部门。例如：

List<Department> departments = new ArrayList<>();
// 添加部门数据
List<Department> leafDepartments = getLeafDepartments(departments, 0);
// 输出所有末级部门
for (Department department : leafDepartments) {
    System.out.println(department.getId());
}