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 org.hibernate.Session;
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 ServiceRegistry serviceRegistry;
static {
try {
configuration.configure();
serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).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(){
if(sessionFactory == null){
return null;
}
if(sessionFactory.getCurrentSession() == null){
return sessionFactory.getCurrentSession();
}else{
return sessionFactory.openSession();
}
}
/**
* 通过测试方法来测试是否正确加载hibernate，并获取到session
* @param args
*/
public static void main(String[] args) {
System.out.println(getSession());
}
}
若运行main方法结果出现
代表环境搭建成功。
时间： 2024-08-29 00:09:16