mybatis入门篇（二）：Mybatis注解方式的基本用法

1、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>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
        <setting name="useGeneratedKeys" value="true"/>
    </settings>

    <typeAliases>
        <package name="com.forest.owl.entity"/>
    </typeAliases>
    
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC">
                <property name="" value=""/>
            </transactionManager>
            <dataSource type="UNPOOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/forest?useSSL=false"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <package name="com.forest.owl.mapper"/>
    </mappers>
</configuration>

2、编写UserMapper接口

package com.forest.owl.mapper;

import com.forest.owl.entity.User;
import org.apache.ibatis.annotations.Select;

public interface UserMapper {
    @Select("SELECT * FROM user WHERE id=#{id}")
    User selectUserById(Long id);
}

3、测试

    @Test
    public void UserMapperTest(){
        SqlSession sqlSession = getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.selectUserById((long) 2);
        System.out.println(user.getUserName());
        System.out.println(user.getHeadImg());
        System.out.println(user.getCreateTime());
    }

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