Mybatis框架

Posted 2022-09-13 mcl2238973568

1. 加入Mybatis相应的架包并解压
2. 创建bean包，在bean包下创建数据库相对应的实体类（创建get、set）
3. 创建dao包，在dao包下创建接口实体类的操作方法
4. 创建resources文件夹，在该文件夹下创建Mybatis的配置文件 
   

    1 <?xml version="1.0" encoding="UTF-8"?>
    2 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
    3 "http://mybatis.org/dtd/mybatis-3-config.dtd">
    4 <!-- 数据源的信息:数据库的信息。 -->
    5 <configuration>
    6     <environments default="development">
    7         <environment id="development">
    8             <transactionManager type="JDBC" />
    9             <dataSource type="POOLED">
   10                 <property name="driver" value="com.mysql.jdbc.Driver" />
   11                 <property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
   12                 <property name="username" value="root" />
   13                 <property name="password" value="root" />
   14             </dataSource>
   15         </environment>
   16     </environments>
   17     
   18 </configuration>

   conf.xml
5. 可以将数据源信息抽取到属性文件jdbc.properties中

   # 数据源信息
   driver=com.mysql.jdbc.Driver
   url=jdbc:mysql://localhost:3306/mybatis
   username=root
   password=root

6. 创建映射包mapper，在该包下创建实体类的映射文件

   <?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.zhiyou100.mcl.mapper.UsersMapper">
       <select id="getUser" parameterType="int"
           resultType="com.zhiyou100.mcl.bean.Users">
           select * from users where id=#id
       </select>
       
       
       <insert id="addUser" parameterType="com.zhiyou100.mcl.bean.Users">
           insert into users(name,age) values(#name,#age)
       </insert>
       
       
       <delete id="deleteUser" parameterType="int">
           delete from users where id=#id
       </delete>
       
       <update id="updateUser" parameterType="com.zhiyou100.mcl.bean.Users">
           update users set name=#name,age=#age where id=#id
       </update>
       
       <select id="selectAll" resultType="Users">
           select * from users
       </select>
       
       <select id="selectByAge" parameterType="map" resultType="Users">
           <![CDATA[select * from users where age>=#min and age<=#max]]>
       </select>
   </mapper>

7. 把属性文件引入到mybatis的配置文件conf.xml中  使用$
8. 将映射文件放入到配置文件中<mappers></mappers>
   

    1 <?xml version="1.0" encoding="UTF-8"?>
    2 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
    3 "http://mybatis.org/dtd/mybatis-3-config.dtd">
    4 <configuration>
    5     <!-- 引入属性文件 -->
    6     <properties resource="jdbc.properties"></properties>
    7     <!-- 为实体类起别名 -->
    8     <typeAliases>
    9         <!-- <typeAlias type="com.zhiyou100.mcl.bean.Users" alias="user"/> -->
   10         <package name="com.zhiyou100.mcl.bean"/>
   11     </typeAliases>
   12     <environments default="development">
   13         <environment id="development">
   14             <transactionManager type="JDBC" />
   15             <dataSource type="POOLED">
   16                 <property name="driver" value="$driver" />
   17                 <property name="url"
   18                     value="$url" />
   19                 <property name="username" value="$username" />
   20                 <property name="password" value="$password" />
   21             </dataSource>
   22         </environment>
   23     </environments>
   24 <-- 多个映射文件放入到同一mappers个里-->
   25 <mappers>
   26 <mapper resource="com/zhiyou100/mcl/mapper/UsersMapper.xml"/>
   27 <mapper resource="com/zhiyou100/mcl/mapper/OrderMapper.xml"/>
   28 <mapper resource="com/zhiyou100/mcl/mapper/ClazzMapper.xml"/>
   29 </mappers>
   30 </configuration>

   mappers
9. 可以为实体类起别名，但是不推荐使用，容易混淆
10. 加入日志信息，方便快速查询错误所在----导入架包log4j.properties。在resources文件夹创建log4j.properties文件
    

    log4j.properties,
    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

    log4j.properties
11. 测试