MyBatis demo

最新推荐文章于 2024-06-15 21:55:18 发布

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导 jar 包：mybatis & mysql 驱动
建立数据库、表、插入值

全局配置文件： mybatis-config.xml

<?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="root"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="EmployeeMapper.xml"/>
    </mappers>
</configuration>

建立数据类型
Emplyee.java

建立映射文件

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

设置映射关系

<?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="EmployeeMapper">  <!-- 任意。如果是接口式，必须是 mapper 文件的全限定名 -->

    <select id="getEmpById" resultType="Employee"> <!-- 任意。如果是接口式，必须是方法名 -->
		select id,last_name lastName,email,gender from employee where id = #{id}
	</select>

</mapper>

测试

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;

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 {
    SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
    SqlSession openSession = sqlSessionFactory.openSession();
    try {
      Employee employee = openSession.selectOne("EmployeeMapper.getEmpById", 1);
      System.out.println(employee);
    } finally {
      openSession.close();
    }
  }

  @Test
  public void test01() throws IOException {
    SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
    SqlSession openSession = sqlSessionFactory.openSession();
    try {
      EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
      Employee employee = mapper.getEmpById(1);
      System.out.println(employee);
    } finally {
      openSession.close();
    }
  }

}