Hibernate_部门查询

向右看齐 2022-06-16 11:56 151阅读 0赞

package cn.itcast.test.dao;
    
    import java.util.List;
    
    import cn.itcast.test.entity.Department;
    
    /**
     * 接口：部门
     * 
     * @author 风清杨
     * @version V5.0
     */
    public interface DepartmentDao {
    	/**
    	 * 增加一个部门
    	 * 
    	 * @param department
    	 *            要增加的部门
    	 */
    	public abstract void save(Department department);
    
    	/**
    	 * 更新一个部门的信息(更改名称)
    	 * 
    	 * @param department
    	 *            要更新的部门
    	 */
    	public abstract void update(Department department);
    
    	/**
    	 * 把部门中所有的员工都取消关联
    	 * 
    	 * @param id
    	 *            要与员工取消关联的部门编号
    	 */
    	public abstract void removeRlieve(Long id);
    
    	/**
    	 * 删除一个部门,并把所有的子部门删掉,如果部门中有员工,则不能删除。
    	 * 
    	 * @param id
    	 *            要删除的部门id
    	 */
    	public abstract void delete(Long id);
    
    	/**
    	 * 根据id查询部门
    	 * 
    	 * @param id
    	 *            部门id
    	 * @return 返回部门
    	 */
    	public abstract Department getById(Long id);
    
    	/**
    	 * 查询最顶级部门,按id升序排列(最顶级的就是没有上级的部门)
    	 * 
    	 * @return 其顶级部门
    	 */
    	public abstract List<Department> parentAsc();
    
    	/**
    	 * 查询某部门的所有子部门,按id升序排序
    	 * 
    	 * @param department
    	 *            要查询的部门
    	 * @return 返回其子部门
    	 */
    	public abstract List<Department> childrenAsc(String department);
    
    	/**
    	 * 员工的总数量,部门的总数量,每个部门中员工的数量。
    	 * 
    	 * @param department
    	 *            要查询的部门
    	 * @return 返回总数
    	 */
    	public abstract QueryResult findCount();
    }

package cn.itcast.test.dao.impl;
    
    import java.util.List;
    
    import org.hibernate.Session;
    import org.hibernate.Transaction;
    
    import cn.itcast.test.dao.DepartmentDao;
    import cn.itcast.test.dao.QueryResult;
    import cn.itcast.test.entity.Department;
    
    /**
     * 实现：部门
     * 
     * @author 风清杨
     * @version V5.0
     */
    public class DepartmentDaoImpl implements DepartmentDao {
    
    	@Override
    	public void save(Department department) {
    		// 打开Session
    		Session session = Utils.getopensession();
    		// 创建事务
    		Transaction tx = null;
    		try {
    			// 开始事务
    			tx = session.beginTransaction();
    			// --------------------------------
    
    			session.save(department);// 保存
    
    			// --------------------------------
    			// 提交事务
    			tx.commit();
    		} catch (RuntimeException e) {
    			// 回滚事务
    			tx.rollback();
    			throw e;
    		} finally {
    			// 释放资源
    			session.close();
    		}
    	}
    
    	@Override
    	public void update(Department department) {
    		// 打开Session
    		Session session = Utils.getopensession();
    		// 创建事务
    		Transaction tx = null;
    		try {
    			// 开始事务
    			tx = session.beginTransaction();
    			// --------------------------------
    
    			session.update(department);
    
    			// --------------------------------
    			// 提交事务
    			tx.commit();
    		} catch (RuntimeException e) {
    			// 回滚事务
    			tx.rollback();
    			throw e;
    		} finally {
    			// 释放资源
    			session.close();
    		}
    
    	}
    
    	@Override
    	public void removeRlieve(Long id) {
    		// 打开Session
    		Session session = Utils.getopensession();
    		// 创建事务
    		Transaction tx = null;
    		try {
    			// 开始事务
    			tx = session.beginTransaction();
    			// --------------------------------
    
    			Department department = (Department) session.get(Department.class, id);
    			department.getEmployee().clear();
    
    			session.update(department);
    			// --------------------------------
    			// 提交事务
    			tx.commit();
    		} catch (RuntimeException e) {
    			// 回滚事务
    			tx.rollback();
    			throw e;
    		} finally {
    			// 释放资源
    			session.close();
    		}
    	}
    
    	@Override
    	public void delete(Long id) {
    		// 打开Session
    		Session session = Utils.getopensession();
    		// 创建事务
    		Transaction tx = null;
    		try {
    			// 开始事务
    			tx = session.beginTransaction();
    			// --------------------------------
    			// 删除一个部门,并把所有的子部门删掉,如果部门中有员工,则不能删除。
    			Department department = (Department) session.get(Department.class, 1L);
    			if (!department.getEmployee().isEmpty()) {
    				System.out.println("该部门有员工");
    			} else {
    				session.delete(department);
    				System.out.println("删除成功");
    			}
    
    			// --------------------------------
    			// 提交事务
    			tx.commit();
    		} catch (RuntimeException e) {
    			// 回滚事务
    			tx.rollback();
    			throw e;
    		} finally {
    			// 释放资源
    			session.close();
    		}
    	}
    
    	@SuppressWarnings("unchecked")
    	@Override
    	public List<Department> parentAsc() {
    		// 打开Session
    		Session session = Utils.getopensession();
    		// 创建事务
    		Transaction tx = null;
    		try {
    			// 开始事务
    			tx = session.beginTransaction();
    			// --------------------------------
    
    			List<Department> list = session.createQuery(//
    					"from Department e where e.parent is null order by e.id asc")//
    					.list();
    
    			// --------------------------------
    			// 提交事务
    			tx.commit();
    			return list;
    		} catch (RuntimeException e) {
    			// 回滚事务
    			tx.rollback();
    			throw e;
    		} finally {
    			// 释放资源
    			session.close();
    		}
    	}
    
    	@SuppressWarnings("unchecked")
    	@Override
    	public List<Department> childrenAsc(String department) {
    		// 打开Session
    		Session session = Utils.getopensession();
    		// 创建事务
    		Transaction tx = null;
    		try {
    			// 开始事务
    			tx = session.beginTransaction();
    			// --------------------------------
    
    			List<Department> list = session.createQuery(//
    					"select d.children from Department d where d.name=:name")//
    					.setParameter("name", department)//
    					.list();
    
    			// --------------------------------
    			// 提交事务
    			tx.commit();
    			return list;
    		} catch (RuntimeException e) {
    			// 回滚事务
    			tx.rollback();
    			throw e;
    		} finally {
    			// 释放资源
    			session.close();
    		}
    	}
    
    	@Override
    	public QueryResult findCount() {
    		// 打开Session
    		Session session = Utils.getopensession();
    		// 创建事务
    		Transaction tx = null;
    		try {
    			// 开始事务
    			tx = session.beginTransaction();
    			// --------------------------------
    			// 员工的总数量
    			Long employeeCount = (Long) session.createQuery(//
    					"select count(e) from Employee e")//
    					.uniqueResult();
    
    			// 部门的总数量
    			Long departmentCount = (Long) session.createQuery(//
    					"select count(d) from Department d")//
    					.uniqueResult();
    			// 每个部门中员工的数量。
    			List<Object> list = session.createQuery(//
    					"select d.name,count(e.name) from Department d join d.employee e group by d.name")//
    					.list();
    
    			// --------------------------------
    			// 提交事务
    			tx.commit();
    			return new QueryResult(employeeCount, departmentCount, list);
    		} catch (RuntimeException e) {
    			// 回滚事务
    			tx.rollback();
    			throw e;
    		} finally {
    			// 释放资源
    			session.close();
    		}
    	}
    
    	@Override
    	public Department getById(Long id) {
    		// 打开Session
    		Session session = Utils.getopensession();
    		// 创建事务
    		Transaction tx = null;
    		try {
    			// 开始事务
    			tx = session.beginTransaction();
    			// ----------------------------------
    
    			Department department = (Department) session.get(Department.class, id);
    
    			// ----------------------------------
    			// 提交事务
    			tx.commit();
    			return department;
    		} catch (RuntimeException e) {
    			// 回滚事务
    			tx.rollback();
    			throw e;
    		} finally {
    			// 释放资源
    			session.close();
    		}
    	}
    
    }