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;
    }
    @Override
    public 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 block
            e.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