第一章-初识mybatis框架
分类: ssm 专栏: ssm框架课 标签: mybatis
2022-11-25 16:42:13 780浏览
第一章-初识mybatis框架
1. 搭建mybatis步骤
1.下载mybatis-3.5.1.jar
可以从maven中央仓库去下载需要的jar.https://mvnrepository.com/
2.将所需jar文件导入工程
3.编写MyBatis核心配置文件
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <properties resource="database.properties"> </properties> <settings> <setting name="logImpl" value="LOG4J"/> </settings> <typeAliases> <!-- <typeAlias type="com.jf3q.part1.pojo.SysUser" alias="sysUser"/>--> <package name="com.jf3q.part1.pojo"/> </typeAliases> <environments default="dev"> <environment id="dev"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="${jdbc.driver}"/> <property name="url" value="${jdbc.url}"/> <property name="username" value="${jdbc.username}"/> <property name="password" value="${jdbc.password}"/> </dataSource> </environment> <environment id="test"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.cj.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/cvs_db?characterEncoding=utf-8&serverTimezone=Asia/Shanghai"/> <property name="username" value="root"/> <property name="password" value="123456"/> </dataSource> </environment> </environments> <mappers> <!-- <mapper resource="com/jf3q/part1/dao/SysUserDao.xml"/>--> <package name="com.jf3q.part1.dao"/> </mappers> </configuration>
4.创建实体类(POJO)
@Data//实现省略get set 方法 toString @AllArgsConstructor//全参构造 @NoArgsConstructor//无参 public class SysUser { private Long id; private String account; private String realName; private String password; private Integer sex; private String birthday; private String phone; private String address; private Long roleId; private Long createdUserId; private Date createdTime; private Long updatedUserId; private Date updatedTime; }
5.定义DAO层Mapper接口
public interface SysUserDao { int count(); List<SysUser> getUserList(); }
6.定义SQL映射文件
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.jf3q.part1.dao.SysUserDao"> <select id="count" resultType="int"> select count(1) from t_sys_user </select> <select id="getUserList" resultType="sysUser"> select * from t_sys_user </select> </mapper>
7.创建测试类
- 读取MyBatis核心配置文件
- 创建SqlSessionFactory实例
- 创建SqlSession实例
- 创建Mapper实例
- 执行SQL映射文件中的SQL语句
public class SysUserDaoTest { @Test public void count() { SqlSession sqlSession = null; try { /*1.读取MyBatis核心配置文件到字符流*/ Reader resourceAsReader = Resources.getResourceAsReader("mybatis-config.xml"); /*2.创建SqlSessionFactory实例*/ SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(resourceAsReader); /*3.创建SqlSession实例*/ sqlSession = sessionFactory.openSession(); /*4.创建Mapper实例*/ // SysUserDao userDao = sqlSession.getMapper(SysUserDao.class); int count = sqlSession.selectOne("com.jf3q.part1.dao.SysUserDao.count"); /*5.执行SQL映射文件中的SQL语句*/ // System.out.println("用户总数:"+userDao.count()); System.out.println("用户总数:"+count); } catch (IOException e) { e.printStackTrace(); }finally { if(sqlSession != null){ sqlSession.close(); } } } @Test public void getAlltest() { SqlSession sqlSession = null; try { sqlSession= MybatisUtils.getSqlSession(); /*4.创建Mapper实例*/ // SysUserDao userDao = sqlSession.getMapper(SysUserDao.class); List<SysUser> userList= sqlSession.selectList("com.jf3q.part1.dao.SysUserDao.getUserList"); /*5.执行SQL映射文件中的SQL语句*/ // List<SysUser> userList = userDao.getUserList(); userList.forEach(u -> System.out.println(u)); } catch (Exception e) { e.printStackTrace(); }finally { MybatisUtils.closeSqlSession(sqlSession); } } }
2.讲课视频教程
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