hibernate第一个案例

实体类：Employee.java

public class Employee {

    private int empId;
    private String empName;
    private Date workDate;
    public int getEmpId() {
        return empId;
    }
    public void setEmpId(int empId) {
        this.empId = empId;
    }
    public String getEmpName() {
        return empName;
    }
    public void setEmpName(String empName) {
        this.empName = empName;
    }
    public Date getWorkDate() {
        return workDate;
    }
    public void setWorkDate(Date workDate) {
        this.workDate = workDate;
    }
    @Override
    public String toString() {
        return "Employee [empId=" + empId + ", empName=" + empName + ", workDate=" + workDate + "]";
    }   
}

映射文件：Employee.hbm.xml

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

<!-- package:要映射的对象所在的包（可选） -->
<hibernate-mapping package="xxx">

    <!-- 
        class 映射某一个对象的(一般情况，一个对象写一个映射文件，即一个class节点)
            name 指定要映射的对象的类型
            table 指定对象对应的表；
                  如果没有指定表名，默认与对象名称一样 
     -->
    <class name="Employee" table="employee">
    <!-- 主键 ，映射-->
        <id name="empId" column="empId">
            <generator class="native"/>
        </id>

        <!-- 
            普通字段映射
            property
                name  指定对象的属性名称
                column 指定对象属性对应的表的字段名称，如果不写默认与对象属性一致。
                length 指定字符的长度, 默认为255
                type   指定映射表的字段的类型，如果不指定会匹配属性的类型
                    java类型：     必须写全名
                    hibernate类型：  直接写类型，都是小写
        -->
        <!-- 非主键，映射 -->
        <property name="empName" column="empName"></property>
        <property name="workDate" column="workDate"></property>

        <!-- 如果列名称为数据库关键字，需要用反引号或改列名。 -->
        <property name="desc" column="`desc`" type="java.lang.String"></property>
    </class>

</hibernate-mapping>

主配置文件：hibernate.cfg.xml

<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <!-- 通常，一个session-factory节点代表一个数据库 -->
    <session-factory>

        <!-- 1. 数据库连接配置 -->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql:///test</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">root</property>
        <!-- 
            数据库方法配置， hibernate在运行的时候，会根据不同的方言生成符合当前数据库语法的sql
         -->
        <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>


        <!-- 2. 其他相关配置 -->
        <!-- 2.1 显示hibernate在运行时候执行的sql语句 -->
        <property name="hibernate.show_sql">true</property>
        <!-- 2.2 格式化sql
        <property name="hibernate.format_sql">true</property>
        -->
        <!-- 2.3 自动建表  -->
        <property name="hibernate.hbm2ddl.auto">update</property>



        <!-- 3. 加载所有映射 -->
        <mapping resource="a_hello/Employee.hbm.xml"/>

    </session-factory>
</hibernate-configuration>

工具类：hibernateUtils.java

public class HibernateUtils {

    private static SessionFactory sf;
    static {
        // 加载主配置文件, 并创建Session的工厂
        sf = new Configuration().configure().addClass(Employee.class).buildSessionFactory();
    }

    // 创建Session对象
    public static Session getSession(){
        return sf.openSession();
    }
}

dao接口设计

IEmployeeDao.java

public interface IEmployeeDao {

    void save(Employee emp);
    void update(Employee emp);
    Employee findById(Serializable id);
    List<Employee> getAll();
    List<Employee> getAll(String employeeName);
    List<Employee> getAll(int index, int count);
    void delete(Serializable id);

}

EmployeeDao.java

public class EmployeeDaoImpl implements IEmployeeDao{

    @Override
    public Employee findById(Serializable id) {
        Session session = null;
        Transaction tx = null;
        try {
            // 获取Session
            session = HibernateUtils.getSession();
            // 开启事务
            tx = session.beginTransaction();
            // 主键查询
            return (Employee) session.get(Employee.class, id);
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            tx.commit();
            session.close();
        }
    }

    @SuppressWarnings("unchecked")
    @Override
    public List<Employee> getAll() {
        Session session = null;
        Transaction tx = null;
        try {
            session = HibernateUtils.getSession();
            tx = session.beginTransaction();
            // HQL查询
            Query q = session.createQuery("from Employee");
            return q.list();
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            tx.commit();
            session.close();
        }
    }

    @SuppressWarnings("unchecked")
    @Override
    public List<Employee> getAll(String employeeName) {
        Session session = null;
        Transaction tx = null;
        try {
            session = HibernateUtils.getSession();
            tx = session.beginTransaction();
            Query q =session.createQuery("from Employee where empName=?");
            // 注意：参数索引从0开始
            q.setParameter(0, employeeName);
            // 执行查询
            return q.list();
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            tx.commit();
            session.close();
        }
    }

    @SuppressWarnings("unchecked")
    @Override
    public List<Employee> getAll(int index, int count) {
        Session session = null;
        Transaction tx = null;
        try {
            session = HibernateUtils.getSession();
            tx = session.beginTransaction();
            Query q = session.createQuery("from Employee");
            // 设置分页参数
            q.setFirstResult(index);  // 查询的其实行 
            q.setMaxResults(count);   // 查询返回的行数

            List<Employee> list = q.list();
            return list;
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            tx.commit();
            session.close();
        }
    }

    @Override
    public void save(Employee emp) {
        Session session = null;
        Transaction tx = null;
        try {
            session = HibernateUtils.getSession();
            tx = session.beginTransaction();
            // 执行保存操作
            session.save(emp);
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            tx.commit();
            session.close();
        }

    }

    @Override
    public void update(Employee emp) {
        Session session = null;
        Transaction tx = null;
        try {
            session = HibernateUtils.getSession();
            tx = session.beginTransaction();
            session.update(emp);

        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            tx.commit();
            session.close();
        }

    }

    @Override
    public void delete(Serializable id) {
        Session session = null;
        Transaction tx = null;
        try {
            session = HibernateUtils.getSession();
            tx = session.beginTransaction();
            // 先根据id查询对象，再判断删除
            Object obj = session.get(Employee.class, id);
            if (obj != null) {
                session.delete(obj);
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            tx.commit();
            session.close();
        }
    }
}

实现类：App.java

public class App {

    private EmployeeDaoImpl empDao = new EmployeeDaoImpl();

    @Test
    public void testFindById() {
        System.out.println(empDao.findById(1));
    }

    @Test
    public void testGetAll() {
        System.out.println(empDao.getAll());
    }

    @Test
    public void testGetAllString() {
        System.out.println(empDao.getAll("3"));
    }

    @Test
    public void testGetAllIntInt() {
        System.out.println(empDao.getAll(4, 2));
    }

    @Test
    public void testSave() {
        empDao.save(new Employee());
    }

    @Test
    public void testUpdate() {
        Employee emp = new Employee();
        emp.setEmpId(1);
        emp.setEmpName("new jack");

        empDao.update(emp);
    }

    @Test
    public void testDelete() {
        empDao.delete(23);
    }

}

配置工具类：App_dll

public class App_ddl {

    // 自动建表
    @Test
    public void testCreate() throws Exception {
        // 创建配置管理类对象
        Configuration config = new Configuration();
        // 加载主配置文件
        config.configure();

        // 创建工具类对象
        SchemaExport export = new SchemaExport(config);
        // 建表
        // 第一个参数： 是否在控制台打印建表语句
        // 第二个参数： 是否执行脚本
        export.create(true, true);
    }
}