public class Department {private Long id;private String name;private String description;private Set<User> users = new HashSet<User>();private Department parent;private Set<Department> children = new HashSet<Department>();public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getDescription() {return description;}public void setDescription(String description) {this.description = description;}public Set<User> getUsers() {return users;}public void setUsers(Set<User> users) {this.users = users;}public Department getParent() {return parent;}public void setParent(Department parent) {this.parent = parent;}public Set<Department> getChildren() {return children;}public void setChildren(Set<Department> children) {this.children = children;}
}

public class Role {private Long id;private String name;private String description;private Set<User> users = new HashSet<User>();public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getDescription() {return description;}public void setDescription(String description) {this.description = description;}public Set<User> getUsers() {return users;}public void setUsers(Set<User> users) {this.users = users;}
}

public class User {private Long id;private Department department;private Set<Role> roles = new HashSet<Role>();private String loginName;    //登录名private String password;    //密码    private String name;        //真实姓名private String gender;        //性别private String phoneNumber;    //电话号码private String email;        //电子邮件private String description;    //说明public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Department getDepartment() {return department;}public void setDepartment(Department department) {this.department = department;}public Set<Role> getRoles() {return roles;}public void setRoles(Set<Role> roles) {this.roles = roles;}public String getLoginName() {return loginName;}public void setLoginName(String loginName) {this.loginName = loginName;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getGender() {return gender;}public void setGender(String gender) {this.gender = gender;}public String getPhoneNumber() {return phoneNumber;}public void setPhoneNumber(String phoneNumber) {this.phoneNumber = phoneNumber;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public String getDescription() {return description;}public void setDescription(String description) {this.description = description;}
}

<hibernate-mapping package="cn.itcast.oa.domain"><class name="Department" table="itcast_department"><id name="id"><generator class="native" /></id><property name="name"></property><property name="description"></property><!-- users属性，本类与User的一对多 --><set name="users"><key column="departmentId"></key><one-to-many class="User"/></set><!-- parent属性，本类与Department(上级)的多对一 --><!-- name属性名 、class关联的实体类型 、column外键--><many-to-one name="parent" class="Department" column="parentId"></many-to-one><!-- children属性，本类与Department(下级)的一对多 --><set name="children"><key column="parentId"></key><one-to-many class="Department"/></set></class>
</hibernate-mapping>

<hibernate-mapping package="cn.itcast.oa.domain"><class name="Role" table="itcast_role"><id name="id"><generator class="native" /></id><property name="name"></property><property name="description"></property><!-- users属性，本类与User的多对多 --><set name="users" table="itcast_user_role"><key column="roleId"></key><many-to-many class="User" column="userId"></many-to-many></set></class>
</hibernate-mapping>

<hibernate-mapping package="cn.itcast.oa.domain"><class name="User" table="itcast_user"><id name="id"><generator class="native" /></id><property name="loginName"/><property name="password"/><property name="name"/><property name="gender"/><property name="phoneNumber"/><property name="email"/><property name="description"/><!-- department属性，本类与Department的多对一 --><!-- name属性名 、class关联的实体类型 、column外键--><many-to-one name="department" class="Department" column="departmentId"></many-to-one><!-- roles属性，本类与Role的多对多 --><set name="roles" table="itcast_user_role"><key column="userId"></key><many-to-many class="Role" column="roleId"></many-to-many></set></class>
</hibernate-mapping>

@Controller
@Scope("prototype")
public class DepartmentAction extends ActionSupport implements ModelDriven<Department>{//这里也需要转递参数id,名称和说明，实体里都有了。所以要实现ModelDriven,封装表单当中传递过来的参数//有接口有实现类，想用它就创建，采用@Resource注入
    @Resourceprivate DepartmentService departmentService;private Long parentId;private Department model = new Department();public Department getModel() {return model;}/*** 列表*/public String list() throws Exception {List<Department> departmentList = departmentService.findAll();//findAll()在DepartmentService接口中创建if(parentId == null) {//等于空就查询顶级//显示顶级部门，设置查询顶级列表即可departmentList = departmentService.findTopList();}else {//查询子部门列表，告诉他我的IddepartmentList = departmentService.findChildren(parentId);}//顶级部门与子部门集合在一起
        ActionContext.getContext().put("departmentList", departmentList);//放在map里面方便拿，#号获取return "list";}/*** 删除*/public String delete() throws Exception {departmentService.delete(model.getId());//delete()在DepartmentService接口中创建return "toList";}/*** 添加页面*/public String addUI() throws Exception {//准备数据，DepartmnetListList<Department> departmentList = departmentService.findAll();ActionContext.getContext().put("departmentList", departmentList);//一般放在值栈中的map，获取用#号获取方便return "saveUI";}/*** 添加*/public String add() throws Exception {//封装到对象中/*Department department = new Department();department.setName(model.getName());department.setDescription(model.getDescription());//保存到数据库中departmentService.save(department);*///关联上级部门Department parent = departmentService.getById(parentId);//根据id查询出相应的对象再关联关系
        model.setParent(parent);//添加的方法可以简化成一行代码
        departmentService.save(model);return "toList";}/*** 修改页面*/public String editUI() throws Exception {//准备数据，DepartmnetListList<Department> departmentList = departmentService.findAll();ActionContext.getContext().put("departmentList", departmentList);//一般放在值栈中的map，获取用#号获取方便//准备回显的数据Department department =departmentService.getById(model.getId());//把回显的数据的id告诉我ActionContext.getContext().getValueStack().push(department);//把它放到栈顶就能回显if(department.getParent() != null) {//回显上级部门parentId = department.getParent().getId();//把数据给parentId
        }return "saveUI";}/*** 修改*/public String edit() throws Exception {//1.从数据库中取出原对象Department department = departmentService.getById(model.getId());//2.设置要修改的属性
        department.setName(model.getName());department.setDescription(model.getDescription());department.setParent(departmentService.getById(parentId));//设置所属的上级部门//3.更新到数据库中
        departmentService.update(department);return "toList";}public void setParentId(Long parentId) {this.parentId = parentId;}public Long getParentId() {return parentId;}
}

//在Action中要调用Service，要写下面两个注解
@Service
@Transactional    //业务层要管理实务，控制开关事务
@SuppressWarnings("unchecked")
public class DepartmentServiceImpl implements DepartmentService{//Service里要调用Dao，得到它通过注入
    @Resourceprivate DepartmentDao departmentDao;@Resourceprivate SessionFactory sessionFactory;public List<Department> findTopList() {return sessionFactory.getCurrentSession().createQuery(//
                "FROM Department d WHERE d.parent IS NULL")//
                .list();}public List<Department> findChildren(Long parentId) {return sessionFactory.getCurrentSession().createQuery(//
                "FROM Department d WHERE d.parent.id=?")//
                .setParameter(0, parentId)//这里的索引0表示上面的问号
                .list();}public List<Department> findAll() {return departmentDao.findAll();}public void delete(Long id) {departmentDao.delete(id);}public void save(Department model) {departmentDao.save(model);}public Department getById(Long id) {return departmentDao.getById(id);}public void update(Department department) {departmentDao.update(department);}
}

//接口中只有方法的声明，没有方法的实现
public interface DepartmentService {List<Department> findAll();void delete(Long id);void save(Department model);Department getById(Long id);void update(Department department);//查询顶级部门列表List<Department> findTopList();//查询子部门列表List<Department> findChildren(Long parentId);}

    public T getById(Long id) {if(id == null) {return null;}else{return (T) getSession().get(clazz, id);}}

　　　　　<!-- parent属性，本类与Department(上级)的多对一 --><!-- name属性名 、class关联的实体类型 、column外键--><many-to-one name="parent" class="Department" column="parentId" lazy="false"></many-to-one><!-- children属性，本类与Department(下级)的一对多 --><set name="children" cascade="delete" lazy="false"><key column="parentId"></key><one-to-many class="Department"/></set>

            //把parent对象事先放到map中，列表通过#号拿到parent对象Department parent = departmentService.getById(parentId);ActionContext.getContext().put("departmentList", departmentList);

　　使用OpenSessionInViewFilter解决解决懒加载问题，在web.xml中配置，一定要配置在struts2之前：<!-- 配置Spring的用于解决懒加载问题的过滤器 --><filter><filter-name>OpenSessionInViewFilter</filter-name><filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class></filter><filter-mapping><filter-name>OpenSessionInViewFilter</filter-name><url-pattern>*.action</url-pattern></filter-mapping>

　　/*** 结构如下：* * ┣市场部*    ┣宣传部*    ┣业务部*       ┣业务一部*       ┣业务二部* ┣开发部*    ┣开发一部*    ┣开发二部* * @return 所有最顶层的部门的列表*/public static List<Department> findTopLevelDepartmentList() {Department dept_1_1 = new Department();dept_1_1.setId(new Long(11));dept_1_1.setName("宣传部");Department dept_1_2 = new Department();dept_1_2.setId(new Long(12));dept_1_2.setName("业务部");Department dept_1_2_1 = new Department();dept_1_2_1.setId(new Long(121));dept_1_2_1.setName("业务一部");Department dept_1_2_2 = new Department();dept_1_2_2.setId(new Long(122));dept_1_2_2.setName("业务二部");dept_1_2_1.setParent(dept_1_2);dept_1_2_2.setParent(dept_1_2);Set<Department> children_0 = new LinkedHashSet<Department>();children_0.add(dept_1_2_1);children_0.add(dept_1_2_2);dept_1_2.setChildren(children_0);// ================================Department dept_1 = new Department();dept_1.setId(new Long(1));dept_1.setName("市场部");dept_1_1.setParent(dept_1);dept_1_2.setParent(dept_1);Set<Department> children_1 = new LinkedHashSet<Department>();children_1.add(dept_1_1);children_1.add(dept_1_2);dept_1.setChildren(children_1);// ---Department dept_2_1 = new Department();dept_2_1.setId(new Long(21));dept_2_1.setName("开发一部");Department dept_2_2 = new Department();dept_2_2.setId((new Long(22)));dept_2_2.setName("开发二部");Department dept_2 = new Department();dept_2.setId(new Long(2));dept_2.setName("开发部");dept_2_1.setParent(dept_2);dept_2_2.setParent(dept_2);Set<Department> children_2 = new LinkedHashSet<Department>();children_2.add(dept_2_1);children_2.add(dept_2_2);dept_2.setChildren(children_2);// ---List<Department> depts = new ArrayList<Department>();depts.add(dept_1);depts.add(dept_2);return depts;}
市场部
宣传部
业务部
业务一部
业务二部
开发部
开发一部
开发二部

　　/*** 练习一：打印所有顶层部门及其子孙部门的信息（名称） 提示：假设有一个 打印部门树 的信息 的方法* * 要求打印如下效果：* * 市场部* 宣传部* 业务部* 业务一部* 业务二部* 开发部* 开发一部* 开发二部*/@Testpublic void printAllDepts_1() {List<Department> topList = findTopLevelDepartmentList();/*// 方式一for (Department top : topList) {showTree(top);//调用自己}*/// 方式二
        showTreeList(topList);}/*** 显示一颗部门树中所有节点的信息* * @param top*            树的顶点（根节点）*/private void showTree(Department top) {// 顶点
        System.out.println(top.getName());// 子树for (Department child : top.getChildren()) {showTree(child);}}/*** 显示多颗树的所有节点的信息* @param topList*/private void showTreeList(Collection<Department> topList) {for (Department top : topList) {// 顶点
            System.out.println(top.getName());// 子树
            showTreeList(top.getChildren());}}

/*** 练习二：打印所有顶层部门及其子孙部门的信息（名称），用不同的缩进表示层次（使用全角空格）。<br>* 子部门的名称前比上级部门多一个空格，最顶层部门的名字前没有空格。 提示：假设有一个打印部门集合中所有部门信息的方法* * 要求打印如下效果：* * ┣市场部*    ┣宣传部*    ┣业务部*       ┣业务一部*       ┣业务二部* ┣开发部*    ┣开发一部*    ┣开发二部*/@Testpublic void printAllDepts_2() {List<Department> topList = findTopLevelDepartmentList();showTreeList_2(topList, "┣");}// 显示树private void showTreeList_2(Collection<Department> topList, String prefix) {for (Department top : topList) {// 顶点System.out.println(prefix + top.getName());// 子树showTreeList_2(top.getChildren(), "    " + prefix);}}