MyBatis搭建过程
1.导入MyBatis框架的jar包、Mysql驱动包、log4j的jar包
myBatis-3.4.1.jar
mysql-connector-java-5.1.37-bin.jar
log4j.jar
2.创建MyBatis的核心（全局）配置文件mybatis-config.xml并配置（如何连接数据库）
3.创建映射文件XxxMapper.xml并配置（如何操作数据库）
4.创建mapper接口，实现两个绑定:
4.1接口全限定名要和映射文件的namespace保持一致
4.2接口中方法名和SQL语句的id保持一致
5.获取MyBatis操作数据库的会话对象SqlSession，通过getMapper()获取接口的动态代理实现类
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
SqlSession sqlSession = sqlSessionFactory.openSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
6、测试
搭建过程案例
1.项目目录
user表
log4j.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
<param name="Encoding" value="UTF-8" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) \n" />
</layout>
</appender>
<logger name="java.sql">
<level value="debug" />
</logger>
<logger name="org.apache.ibatis">
<level value="info" />
</logger>
<root>
<level value="debug" />
<appender-ref ref="STDOUT" />
</root>
</log4j:configuration>
2.导入上图中所示的jar包
3.jdbc.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm
jdbc.username=root
jdbc.password=root
4.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>
<!-- <properties>
<property name="jdbc.driver" value="com.mysql.jdbc.Driver"/>
</properties> -->
<!--
<properties>:设置或引入资源文件
resource:在类路径下访问资源文件
url:在网络路径或磁盘路径下访问资源文件
-->
<properties resource="jdbc.properties"></properties>
<settings>
<setting name="mapUnderscoreToCamelCase" value="true"></setting>
</settings>
<typeAliases>
<!--
为类型设置类型别名
type:Java类型，若只设置type，默认的别名就是类型，且不区分大小写
-->
<!-- <typeAlias type="com.atguigu.bean.User" alias="User"/> -->
<package name="com.atguigu.bean"/>
</typeAliases>
<!--
<environments>:设置连接数据库的环境
default:设置默认使用的数据库环境
-->
<environments default="development">
<!--
<environment>:设置某个具体的数据库环境
id:数据库环境的唯一标识
-->
<environment id="development">
<!--
type="JDBC|MANAGED"
-->
<transactionManager type="JDBC" />
<!--
type="POOLED|UNPOOLED|JNDI"
-->
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
</dataSource>
</environment>
</environments>
<!-- 引入映射文件 -->
<mappers>
<mapper resource="UserMapper.xml" />
</mappers>
</configuration>
5.User.java
package com.atguigu.bean;
public class User {
private Integer uid;
private String userName;
private String password;
private Integer age;
private String sex;
public Integer getUid() {
return uid;
}
public void setUid(Integer uid) {
this.uid = uid;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
@Override
public String toString() {
return "User [uid=" + uid + ", userName=" + userName + ", password=" + password + ", age=" + age + ", sex="
+ sex + "]";
}
}
6.UserMapper.xml(举例：操作数据库中的user表)
<?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.atguigu.mapper.UserMapper">
<!--
<select>:定义查询语句
id:设置SQL语句的唯一标识
resultType:结果类型，即实体类的全限定名
-->
<select id="getUserByUid" resultType="User">
<!--
当数据库表中的字段与类中的属性名不一样时，可以在查询时指定别名
select uid,user_name userName,password,age,sex from user where uid = #{id}
-->
<!--
当数据库表中的字段与类中的属性名不一样时，如果不指定别名，需要在核心配置文件mybatis-config.xml中做以下配置：
<settings>
<setting name="mapUnderscoreToCamelCase" value="true"></setting>
</settings>
注：此配置通常不使用，即在开发时将数据库的字段名与类的属性名保持一致
-->
select uid,user_name,password,age,sex from user where uid = #{id}
</select>
</mapper>
7.UserMapper.java(mapper接口)
package com.atguigu.mapper;
import com.atguigu.bean.User;
public interface UserMapper {
User getUserByUid(String uid);
}
8.TestMybatis.java(测试类)
package com.atguigu.mapper;
import java.io.IOException;
import java.io.InputStream;
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 com.atguigu.bean.User;
public class TestMybatis {
@Test
public void test() throws IOException{
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
SqlSession sqlSession = sqlSessionFactory.openSession();
//getMapper():会通过动态代理动态生成UserMapper的代理实现类
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
//System.out.println(mapper.getClass().getName());
User user = mapper.getUserByUid("1");
System.out.println(user);
}
}