mybatis学习(15):mybatis连接mysql数据库

目录结构

com.geyao.mybatis.mapper

BlogMapper类

package com.geyao.mybatis.mapper;import com.geyao.mybatis.pojo.Blog;public interface BlogMapper {Blog selectBlog(String id);
}

BlogMapper.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">
<!-- 为这个mapper指定一个唯一的namespace，namespace的值习惯上设置成包名+sql映射文件名，这样就能够保证namespace的值是唯一的
例如namespace="me.gacl.mapping.userMapper"就是me.gacl.mapping(包名)+userMapper(userMapper.xml文件去除后缀)-->
<mapper namespace="com.geyao.mybatis.mapper.BlogMapper"><!-- 在select标签中编写查询的SQL语句， 设置select标签的id属性为getUser，id属性值必须是唯一的，不能够重复使用parameterType属性指明查询时使用的参数类型，resultType属性指明查询返回的结果集类型resultType="me.gacl.domain.User"就表示将查询结果封装成一个User类的对象返回User类就是users表所对应的实体类--><!-- 根据id查询得到一个user对象--><select id="selectBlog"  resultType="Blog">select * from Blog where id=#{id}</select>
</mapper>

com.geyao.mybatis.pojo

Blog类

package com.geyao.mybatis.pojo;public class Blog {private String id;private String title;private int authod_id;private String state;private Boolean featured;private String style;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public int getAuthod_id() {return authod_id;}public void setAuthod_id(int authod_id) {this.authod_id = authod_id;}public String getState() {return state;}public void setState(String state) {this.state = state;}public Boolean getFeatured() {return featured;}public void setFeatured(Boolean featured) {this.featured = featured;}public String getStyle() {return style;}public void setStyle(String style) {this.style = style;}@Overridepublic String toString() {return "Blog [id=" + id + ", title=" + title + ", authod_id=" + authod_id + ", state=" + state + ", featured="+ featured + ", style=" + style + "]";}}

com.geyao.mybatis.util

MybatisUtil类

package com.geyao.mybatis.util;import java.io.InputStream;
import java.io.Reader;import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;public class MyBatisUtil {private static SqlSessionFactory sqlSessionFactory =null;static {try {InputStream in = Resources.getResourceAsStream("mybatis-config.xml");sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}private MyBatisUtil() {}public static SqlSession getSqlSession() {return sqlSessionFactory.openSession();}
}

log4j.properties

### \u914D\u7F6E\u6839 ###
log4j.rootLogger = debug,console ,fileAppender,dailyRollingFile,ROLLING_FILE,MAIL,DATABASE### \u8BBE\u7F6E\u8F93\u51FAsql\u7684\u7EA7\u522B\uFF0C\u5176\u4E2Dlogger\u540E\u9762\u7684\u5185\u5BB9\u5168\u90E8\u4E3Ajar\u5305\u4E2D\u6240\u5305\u542B\u7684\u5305\u540D ###
log4j.logger.org.apache=dubug
log4j.logger.java.sql.Connection=dubug
log4j.logger.java.sql.Statement=dubug
log4j.logger.java.sql.PreparedStatement=dubug
log4j.logger.java.sql.ResultSet=dubug### \u914D\u7F6E\u8F93\u51FA\u5230\u63A7\u5236\u53F0 ###
log4j.appender.console = org.apache.log4j.ConsoleAppender
log4j.appender.console.Target = System.out
log4j.appender.console.layout = org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern =  %d{ABSOLUTE} %5p %c{1}:%L - %m%n

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><typeAliases><typeAlias type="com.geyao.mybatis.pojo.Blog" alias="Blog"/>
</typeAliases><environments default="development"><environment id="development"><transactionManager type="JDBC" /><!-- 配置数据库连接信息 --><dataSource type="POOLED"><property name="driver" value="com.mysql.cj.jdbc.Driver" /><property name="url" value="jdbc:mysql://localhost:3306/mybatis?serverTimezone=GMT%2B8" /><property name="username" value="root" /><property name="password" value="123" /></dataSource></environment></environments><mappers><!-- 注册userMapper.xml文件， userMapper.xml位于me.gacl.mapping这个包下，所以resource写成me/gacl/mapping/userMapper.xml--><mapper resource="com/geyao/mybatis/mapper/BlogMapper.xml"/></mappers>
</configuration>

单元测试

com.geyao.mybatis.util

testSelectBlog类

package com.geyao.mybatis.mapper;import org.apache.ibatis.session.SqlSession;
import org.junit.Test;import com.geyao.mybatis.pojo.Blog;
import com.geyao.mybatis.util.MyBatisUtil;public class testSelectBlog {
@Test
public void testSelectBlog() {SqlSession session =MyBatisUtil.getSqlSession();BlogMapper blogMapper =session.getMapper(BlogMapper.class);Blog blog = blogMapper.selectBlog("1");System.out.println(blog);
}
}

jar包

链接：https://pan.baidu.com/s/1g6NgzfLc5uK9S4VL-03lHg
提取码：4r2m

运行结果