一、MyBatis 核心配置文件

一、mybatis.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>
    <!-- properties加载外部文件 -->
    <properties resource="db.properties"/>

    <!-- 设置MyBatis使用log4j日志支持 -->
    <settings>
        <setting name="logImpl" value="LOG4J"/>
    </settings>

    <!-- typeAliases给类型起别名 -->
    <typeAliases>
        <package name="com.pojo"/>
    </typeAliases>
    
    <!--用于指定使用哪个环境，default:用于指定使用的环境id-->
    <environments default="dev">
        <!--用于配置开发环境，id:环境的唯一识别码-->
        <environment id="dev">
            <!--事务管理器，type: 用于设置mybatis采用什么方式管理事务，JDBC表示采用和JDBC一样的事务管理方式-->
            <transactionManager type="JDBC"></transactionManager>
            <!--数据源/连接池, 用于配置连接池和数据库连接的参数，type: 用于设置mybatis是否采用连接池技术，POOLED表示MyBatis采用连接池技术-->
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    
    <mappers>
        <!--<mapper class="com.mapper.UserMapper"/>-->
        <package name="com.mapper"/>
    </mappers>

</configuration>

二、mapper.xml

<?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">
<!--namespace: 命名空间, 可以随意定义, 一般情况下要写全限定路径
MyBatis管理SQL语句是通过namespace+id来定位的-->
<mapper namespace="com.mapper.ClazzMapper">
    <!--开启二级缓存-->
    <cache/>
</mapper>

三、log4j.properties

# Set root category priority to INFO and its only appender to CONSOLE.
log4j.rootCategory= ERROR, CONSOLE
#log4j.rootCategory=DEBUG, CONSOLE, LOGFILE

# 单独设置SQL语句的输出级别为DEBUG级别
# 方法级别
# log4j.logger.com.mapper.UserMapper.selAll=DEBUG
# 类级别
# log4j.logger.com.mapper.UserMapper=DEBUG
# 包级别
# log4j.logger.com.mapper=DEBUG
log4j.logger.com.mapper=DEBUG

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender

log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=- %m %n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=e:/log4jTest.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=- %m %l %d{yyyy-MM-dd hh:mm:ss} %n

四、db.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/db_books?useUnicode=true&characterEncoding=utf-8
username=root
password=123456