hibernate 实现增删改查

HibernateUtil 和 jar包和demo中一致，这里不再列出。

 

1.实体类

 

public class Dept {
	private String deptId;
	private String deptName;
	private String deptPid;
        // getter,setter 方法
}

 

public class User {

	private String id;
	private String userName;
	private String password;
	private String trueName;
       //其他字段省略。。
	private String enabled;

	private Dept dept; //关联
       //getter、setter方法
}

 2.数据库与PO类映射文件

Dept.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
	<class name="org.hibernate.po.Dept" table="ROMS_SYS_DEPT">
		<id name="deptId" type="java.lang.String" column="DEPT_ID">
		<!-- 	  <generator class="uuid"> </generator>  -->
		</id>
		<property name="deptName" type="java.lang.String" column="DEPT_NAME"/>
		<property name="deptPid" type="java.lang.String" column="PDEPT_ID"/>
	</class>
</hibernate-mapping>

 User.hbm.xml

<hibernate-mapping>
	<class name="org.hibernate.po.User" table="ROMS_SYS_USER">
		<id name="id" type="java.lang.String" column="ID" >
			<generator class="uuid"> </generator>
		</id>
		<property name="userName" type="java.lang.String" column="USERNAME" />
		<property name="password" type="java.lang.String" column="PASSWORD" />
		<property name="trueName" type="java.lang.String" column="TRUENAME" />
		<property name="enabled" type="java.lang.String" column="ENABLED" />
		<many-to-one name="dept" class="org.hibernate.po.Dept" column="DEPT_ID" cascade="save-update" fetch="join" lazy="false"></many-to-one> 
		<!-- fetch="join" 默认关联查询时是两条sql语句，设置为join，则一条sql语句，对session.get()起作用-->
		<!-- lazy="false" 取消延缓加载机制 -->
	</class>
</hibernate-mapping>

3.sql文件

 

DROP TABLE IF EXISTS `ROMS_SYS_USER`;
CREATE TABLE `ROMS_SYS_USER` (
  `ID` varchar(32) CHARACTER SET utf8 NOT NULL DEFAULT '',
  `USERNAME` varchar(10) CHARACTER SET utf8 DEFAULT NULL,
  `PASSWORD` varchar(32) CHARACTER SET utf8 DEFAULT NULL,
  `TRUENAME` varchar(20) CHARACTER SET utf8 DEFAULT NULL,
  `AREA_ID` varchar(32) CHARACTER SET utf8 DEFAULT NULL,
  `DEPT_ID` varchar(32) CHARACTER SET utf8 DEFAULT NULL,
  `ENABLED` char(1) CHARACTER SET utf8 DEFAULT NULL,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

  

Dept建表 与demo一致，省略

 

新增

1.直接增加部门

		Dept dept = new Dept();
		dept.setDeptId("444445555");
		dept.setDeptName("测试部门");
		dept.setDeptPid("000");

		Session session = HibernateUtil.getSessionFactory().openSession();
		session.beginTransaction();
		session.save(dept);
		session.getTransaction().commit();
		session.close();

 如果dept设置为随机数，则设置的id无效

<generator class="uuid"> </generator>

 如果不设置id的生成规则，再次插入会报主键重复。

 

2.增加人员

		Dept dept = new Dept();
		dept.setDeptId("5555");

		// 直接添加人员
		User user = new User();
		user.setDept(dept);
		user.setEnabled("1");
		user.setUserName("张三");

		Session session = HibernateUtil.getSessionFactory().openSession();

		session.beginTransaction();
		session.save(dept);
		session.getTransaction().commit();
		session.close();

 增加人员时，可以不增加部门。

但如果增加部门id，并且设置 cascade="save-update" ，如果数据库中部门表有该id，则修改，没有则新增。

 

删除

1.删除部门id为44444的记录

		Dept dept = new Dept();
		dept.setDeptId("44444");

		Session session = HibernateUtil.getSessionFactory().openSession();

		session.beginTransaction();
		session.delete(dept);
		session.getTransaction().commit();
		session.close();

部门存在，则删除 

 

修改

1.修改部门

		Dept dept = new Dept();
		dept.setDeptId("1111");
		dept.setDeptName("测试部门");
		dept.setDeptPid("001");

		Session session = HibernateUtil.getSessionFactory().openSession();

		session.beginTransaction();
		session.update(dept);
		session.getTransaction().commit();
		session.close();

 修改编号为1111的部门，不存在则报错

 

查询

1、查询部门所有

                Session session = HibernateUtil.getSessionFactory().openSession();
		Query query = session.createQuery("from Dept");

		List<Dept> list = query.list();

		for (Dept dept : list) {
			System.out.println(dept.getDeptName());
		}

		session.close();

 

 2.根据id查询

 

                Session session = HibernateUtil.getSessionFactory().openSession();
		session.beginTransaction();
                //load 延缓加载，get 非延缓加载
		User user = (User) session.load(User.class,
				"0de19b0e517747778ba1da9203eec2b3");

		String userName = user.getUserName();
		System.out.println(userName);

		String deptName = user.getDept().getDeptName();
		System.out.println(deptName);

		session.getTransaction().commit();
		session.close();

 

 

3.根据其他字段查询

 

                Session session = HibernateUtil.getSessionFactory().openSession();
		Query query = session
				.createQuery("from User u left outer join fetch u.dept where u.userName=?");
		query.setParameter(0, "BJ0008");
                //非延缓加载
		List<User> list = query.list();
		for (User user : list) {
			System.out.println(user.getUserName());
			System.out.println(user.getDept().getDeptName());
		}
                //延缓加载 
		// Iterator<User> users = query.iterate();
		// while (users.hasNext()) {
		// User user = users.next();
		// System.out.println(user.getUserName());
		// }
		session.close();