Mybatis学习笔记4 – 获取自增主键的值

获取自增主键的值：
mysql支持自增主键，自增主键值的获取，mybatis也是利用statement.getGenreatedKeys()；
useGeneratedKeys=”true”；使用自增主键获取主键值策略
keyProperty；指定对应的主键属性，也就是mybatis获取到主键值以后，将这个值封装给javaBean的哪个属性

1、接口定义

package com.mybatis.dao;import com.mybatis.bean.Employee;public interface EmployeeMapper {
    public void addEmp(Employee employee);
}

2、mapper定义

<?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.mybatis.dao.EmployeeMapper">
    <!-- parameterType：参数类型，可以省略，
获取自增主键的值：
mysql支持自增主键，自增主键值的获取，mybatis也是利用statement.getGenreatedKeys()；
useGeneratedKeys="true"；使用自增主键获取主键值策略
keyProperty；指定对应的主键属性，也就是mybatis获取到主键值以后，将这个值封装给javaBean的哪个属性
-->
    <insert id="addEmp" parameterType="com.mybatis.bean.Employee" useGeneratedKeys="true" keyProperty="id">
        insert into tbl_employee(last_name, gender, email)
        values (#{lastName},#{gender},#{email})
    </insert>
</mapper>

3、测试代码

package com.mybatis.demo;import java.io.IOException;
import java.io.InputStream;import com.mybatis.bean.Employee;
import com.mybatis.dao.EmployeeMapper;
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;public class MyTest {
    public SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(inputStream);
    }    @Test
    public void testAdd() throws IOException {
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
        SqlSession openSession = sqlSessionFactory.openSession(true);
        try {
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            Employee employee = new Employee("jetty", "jetty@126.com", 1);
            mapper.addEmp(employee);
            System.out.println(employee.getId());
        } finally {
            openSession.close();
        }
    }
}