mybatis（入门案例）

mybatis是支持定制化sql、存储过程以及高级映射的优秀持久层框架

 

mybatis避免了几乎所有的jdbc代码和手动设置参数以及获取结果集

 

mybatis可以使用 简单的xml或者注解方式用于配置和原始映射，将接口i和java的pojo（普通的java对象）映射成数据库中的记录

 

mybatis入门：

 

mapper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.atguigu.mybatis.dao.EmployeeMapper"> <!-- namespace:名称空间;指定为接口的全类名 id：唯一标识 resultType：返回值类型 #{id}：从传递过来的参数中取出id值 public Employee getEmpById(Integer id); --> <select id="getEmpById" resultType="com.bean.Employee"> select id,last_name lastName,email,gender from tbl_employee where id = #{id} </select> </mapper>

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> <environments default="development"> <environment id="development"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://localhost:3306/mybatis" /> <property name="username" value="root" /> <property name="password" value="123456" /> </dataSource> </environment> </environments> <mappers> <mapper resource="EmployeeMapper.xml" /> </mappers> </configuration>

测试用例：

public class MyBatisTest { public SqlSessionFactory getSqlSessionFactory() throws IOException { String resource = "mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); return new SqlSessionFactoryBuilder().build(inputStream); } @Test public void test() throws IOException { // 2、获取sqlSession实例，能直接执行已经映射的sql语句 // sql的唯一标识：statement Unique identifier matching the statement to use. // 执行sql要用的参数：parameter A parameter object to pass to the statement. SqlSessionFactory sqlSessionFactory = getSqlSessionFactory(); SqlSession openSession = sqlSessionFactory.openSession(); try { Employee employee = openSession.selectOne("com.mybatis.EmployeeMapper.selectEmp", 1); System.out.println(employee); } finally { openSession.close(); } } }

 

 

 

接口式编程：

public interface EmployeeMapper { public Employee getEmpById(Integer id); }

测试：

@Test public void test() throws IOException { // 1、获取sqlSessionFactory对象 SqlSessionFactory sqlSessionFactory = getSqlSessionFactory(); // 2、获取sqlSession对象 SqlSession openSession = sqlSessionFactory.openSession(); try { // 3、获取接口的实现类对象 EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class); Employee employee = mapper.getEmpById(1); System.out.println(mapper.getClass()); System.out.println(employee); } finally { openSession.close(); } }

 

 

 

 

          

 

转载于:https://www.cnblogs.com/lzb0803/p/9004526.html

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