基于maven搭建hibernate运行环境

准备案例需要的数据库表和测试数据

建表语句：

create table DEPARTMENT (
   DEPT_ID integer not null,
   DEPT_NAME varchar(255) not null,
   DEPT_NO varchar(20) not null,
   LOCATION varchar(255),
   primary key (DEPT_ID),
   unique (DEPT_NO)
);

create table EMPLOYEE (
   EMP_ID bigint not null,
   EMP_NAME varchar(50) not null,
   EMP_NO varchar(20) not null,
   HIRE_DATE date not null,
   IMAGE longblob,
   JOB varchar(30) not null,
   SALARY float not null,
   DEPT_ID integer not null,
   MNG_ID bigint,
   primary key (EMP_ID),
   unique (EMP_NO)
);

create table SALARY_GRADE (
   GRADE integer not null,
   HIGH_SALARY float not null,
   LOW_SALARY float not null,
   primary key (GRADE)
);

create table TIMEKEEPER (
   Timekeeper_Id varchar(36) not null,
   Date_Time datetime not null,
   In_Out char(1) not null,
   EMP_ID bigint not null,
   primary key (Timekeeper_Id)
);

alter table EMPLOYEE
   add index FK75C8D6AE269A3C9 (DEPT_ID),
   add constraint FK75C8D6AE269A3C9
   foreign key (DEPT_ID)
   references DEPARTMENT (DEPT_ID);

alter table EMPLOYEE
   add index FK75C8D6AE6106A42 (EMP_ID),
   add constraint FK75C8D6AE6106A42
   foreign key (EMP_ID)
   references EMPLOYEE (EMP_ID);

alter table EMPLOYEE
   add index FK75C8D6AE13C12F64 (MNG_ID),
   add constraint FK75C8D6AE13C12F64
   foreign key (MNG_ID)
   references EMPLOYEE (EMP_ID);

alter table TIMEKEEPER
   add index FK744D9BFF6106A42 (EMP_ID),
   add constraint FK744D9BFF6106A42
   foreign key (EMP_ID)
   references EMPLOYEE (EMP_ID);

初始化数据

insert into Department (DEPT_ID, DEPT_NAME, DEPT_NO, LOCATION)
values (10, 'ACCOUNTING', 'D10', 'NEW YORK');

insert into Department (DEPT_ID, DEPT_NAME, DEPT_NO, LOCATION)
values (20, 'RESEARCH', 'D20', 'DALLAS');

insert into Department (DEPT_ID, DEPT_NAME, DEPT_NO, LOCATION)
values (30, 'SALES', 'D30', 'CHICAGO');

insert into Department (DEPT_ID, DEPT_NAME, DEPT_NO, LOCATION)
values (40, 'OPERATIONS', 'D40', 'BOSTON');

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7839, 'KING', 'E7839', Str_To_Date('17-11-1981', '%d-%m-%Y'), 'PRESIDENT', 5000, 10, null);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7566, 'JONES', 'E7566', Str_To_Date('02-04-1981', '%d-%m-%Y'), 'MANAGER', 2975, 20, 7839);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7902, 'FORD', 'E7902', Str_To_Date('03-12-1981', '%d-%m-%Y'), 'ANALYST', 3000, 20, 7566);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7369, 'SMITH', 'E7369', Str_To_Date('17-12-1980', '%d-%m-%Y'), 'CLERK', 800, 20, 7902);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7698, 'BLAKE', 'E7698', Str_To_Date('01-05-1981', '%d-%m-%Y'), 'MANAGER', 2850, 30, 7839);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7499, 'ALLEN', 'E7499', Str_To_Date('20-02-1981', '%d-%m-%Y'), 'SALESMAN', 1600, 30, 7698);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7521, 'WARD', 'E7521', Str_To_Date('22-02-1981', '%d-%m-%Y'), 'SALESMAN', 1250, 30, 7698);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7654, 'MARTIN', 'E7654', Str_To_Date('28-09-1981', '%d-%m-%Y'), 'SALESMAN', 1250, 30, 7698);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7782, 'CLARK', 'E7782', Str_To_Date('09-06-1981', '%d-%m-%Y'), 'MANAGER', 2450, 30, 7839);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7788, 'SCOTT', 'E7788', Str_To_Date('19-04-1987', '%d-%m-%Y'), 'ANALYST', 3000, 20, 7566);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7844, 'TURNER', 'E7844', Str_To_Date('08-09-1981', '%d-%m-%Y'), 'SALESMAN', 1500, 30, 7698);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7876, 'ADAMS', 'E7876', Str_To_Date('23-05-1987', '%d-%m-%Y'), 'CLERK', 1100, 20, 7698);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7900, 'ADAMS', 'E7900', Str_To_Date('03-12-1981', '%d-%m-%Y'), 'CLERK', 950, 30, 7698);

insert into Employee (EMP_ID, EMP_NAME, EMP_NO, HIRE_DATE, JOB, SALARY, DEPT_ID, MNG_ID)
values (7934, 'MILLER', 'E7934', Str_To_Date('23-01-1982', '%d-%m-%Y'), 'CLERK', 1300, 10, 7698);

insert into Salary_Grade (GRADE, HIGH_SALARY, LOW_SALARY)
values (1, 9999, 3001);

使用idea新建一个空的maven工程，并在该项目中增加hibernate的依赖、jdbc驱动依赖、log4j日志依赖、junit依赖。

该项目的pom.xml文件依赖内容如下：

 <dependencies>
    <!--junit依赖，用于单元测试-->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
    <!--添加hibernate的核心依赖-->
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-core</artifactId>
      <version>5.0.12.Final</version>
    </dependency>
    <!--添加mysql的jdbc驱动-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.41</version>
    </dependency>
    <!--添加log4j依赖-->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>
  </dependencies>

在resource目录下新建hibernate配置文件，hibernate.cfg.xml，该配置文件为hibernate的全局配置文件，用于定义hibernate的一些全局配置。目前仅配置数据库连接的相关信息

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>
        <!-- Database connection settings -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/dept?serverTimezone=UTC</property>
        <property name="connection.username">root</property>
        <property name="connection.password">12345678</property>

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        <!-- SQL dialect ,定义数据库方言-->
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>
    </session-factory>

</hibernate-configuration>

每种数据库都有一个单独的方言， 例如：

Oracle方言：

• org.hibernate.dialect.Oracle10gDialect(Dùngcho 10g＆11g)
• org.hibernate.dialect.Oracle12cDialect

SQL Server方言：

• org.hibernate.dialect.SQLServerDialect并
• org.hibernate.dialect.SQLServer2012Dialect
• org.hibernate.dialect.SQLServer2008Dialect

MySQL方言

• org.hibernate.dialect.MySQLDialect
• org.hibernate.dialect.MySQL5Dialect

什么是方言？

Dialect是一个使用Hibernate的方式将数据库的数据类型转换为Java的数据类型，反之亦然。此外，它用于定义将HSQL(Hibernate SQL)的函数转换为数据中的函数的方式，如下列出的一部分 -

Java SQL类型	Oracle	MySQL	SQL Server
Types.BIT	number(1,0)	bit	bit
Types.BIGINT	number(19,0)	bigin	bigint
Types.DATE	date	date	date
…….	…	…	…
Types.CLOB	clob	longtext	varchar(MAX)
Types.BLOB	blob	longblob	varbinary(MAX)

创建HibernateUtils类，用于加载hibernate配置信息，以及提供获取session的方法，代码如下:

package com.deng.hibernate.util;

import com.deng.hibernate.bean.Department;
import com.deng.hibernate.bean.Employee;
import org.hibernate.Session;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

/**
 * hibernate工具类
 */
public class HibernateUtils {

    private static org.hibernate.SessionFactory sessionFactory;

    private static Configuration configuration = new Configuration();
    private static StandardServiceRegistry serviceRegistry;

    static {
        try {
            configuration.configure("hibernate.cfg.xml");
            serviceRegistry = new StandardServiceRegistryBuilder().configure().build();
            sessionFactory = configuration.buildSessionFactory(serviceRegistry);
        } catch (Exception e) {
            System.err.println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }

    /**
     * 获取session，所有的hibernate操作均基于session进行
     * @return
     */
    public static Session getSession(){
        return sessionFactory.openSession();
    }

}

若运行main方法结果出现

代表环境搭建成功。