加载数据库配置，类的别名和log4j

1）连接数据库的配置单独放在一个 properties 文件中

2）为实体类定义别名,简化 sql 映射 xml 文件中的引用

3）可以在 src 下加入 log4j 的配置文件,打印日志信息

<?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>
	<!-- 读取数据库配置文件 -->
	<properties resource="day3/db.properties">
		<!-- 存在属性覆盖 -->
		<!-- <property name="" value=""/> -->
	</properties>
	
	<!-- 配置实体类的别名 -->
	<typeAliases>
		<typeAlias type="com.hous.day3.User" alias="_User"/>
		<package name="com.hous.day3"/>
	</typeAliases>

	<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="com/hous/day3/userMapper.xml" />
	</mappers>
</configuration>

 

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis
username=root
password=root

 

<?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.hous.day3.userMapper">
	<!-- 此处使用typeAliases配置的实体类别名 -->
	<insert id="addUser" parameterType="_User">
		insert into users(name, age) values(#{name},#{age})
	</insert>
	
	<delete id="deleteUser" parameterType="int">
		delete from users where id=#{id}
	</delete>
	<!-- 此处使用typeAliases配置的实体类别名 -->
	<update id="updateUser" parameterType="User">
		update users set name=#{name},age=#{age} where id=#{id}
	</update>
	
	<select id="getUser" parameterType="int" resultType="com.hous.day3.User">
		select * from users where id=#{id}
	</select>
	
	<select id="getAllUsers" resultType="com.hous.day3.User">
		select * from users
	</select>
	
</mapper>

 

log4j.rootLogger=DEBUG, Console

#Console
log4j.appender.Console=org.apache.log4j.ConsoleAppender
log4j.appender.Console.layout=org.apache.log4j.PatternLayout
log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n
log4j.logger.java.sql.ResultSet=INFO
log4j.logger.org.apache=INFO
log4j.logger.java.sql.Connection=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG