[Java知识库]mybatis(1)-简单使用

1. 要操作的表

2. 使用maven创建项目

3. 导入坐标

 <dependencies>
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.4.5</version>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.6</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

4. 编写user表对应的实体类

5.? user的配置文件

<?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">
<!-- namespace：命名空间 -->
<mapper namespace="test">
    <!-- 通过id查询数据  id是名字 parameterType 要传入参数的类型  resultType返回值的类型 中间对应sql -->
    <select id="findUserById" parameterType="Integer" resultType="org.example.User">
        select *
        from user
        where id = #{v}
    </select>


    <!-- 数据插入 selectKey 需要返回的值 -->
    <insert id="insertUser" parameterType="org.example.User" useGeneratedKeys="true">
        <selectKey keyProperty="id" resultType="Integer" order="AFTER">
            select LAST_INSERT_ID()
        </selectKey>
        insert into user (name) values(#{name})
    </insert>
</mapper>

?6. mybatis配置文件

<?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>
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <!--连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/test"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>

    <!--指定映射配置文件的位置，映射配置文件指的是每个dao独立的配置文件-->
    <mappers>
        <mapper resource="User.xml"/>
    </mappers>
</configuration>

?7. db操作