mybatis学习(15):mybatis连接mysql数据库

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.pojoBlog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.utilMybatisUtil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);
 }
 }