MyBatis实战总结

1、导入相关的jar包：mysql.jar、mybatis3.jar

2、src下,编写mysql.properties文件

driver=com.mysql.jdbc.Driver url=jdbc:mysql://localhost:3306/cs_db username=root password=123

3、src下编写mybatis-config.xml总配置文件

XML申明: <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">ML样例: <?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> <!-- 驱动配置文件 --> <properties resource="mysql.properties"/> <!-- 别名映射 --> <typeAliases> <!-- 自动扫描包下的Bean --> <package name="me.mxzf.domain"/> <typeAlias type="me.mxzf.domain.Student" alias="Student"/> </typeAliases> <!-- 环境 --> <environments default="development"> <environment id="development"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="${driver}" /> <property name="url" value="${url}" /> <property name="username" value="${username}" /> <property name="password" value="${password}" /> </dataSource> </environment> </environments> <!-- Bean映射Sql文件 --> <mappers> <mapper resource="me/mxzf/mapping/StudentMapper.xml" /> </mappers> </configuration>

4、编写对应的类的sql映射文件

XML申明: <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> XML样例: <?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="me.mxzf.mapping.StudentMapper"> <select id="selectStudent" resultType="Student"> select * from student where sid = #{sid} </select> </mapper>

6、通过namespace+id的方式去访问对应的sql语句

//从XML中构建SqlSessionFactory //如果配置文件在src目录下，resource = "mybatis-config.xml"; //否则resource = 具体的包路径 + 文件名 String resource = "org/mybatis/example/mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); //在总配置文件中mappers里注册所有的sql映射文件 <mapper resource="me/mxzf/mapping/StudentMapper.xml"/> ... //从SqlSessionFactory中获取SqlSession SqlSession session = sessionFactory.openSession(); try { //me.mxzf.mapping.StudentMapper 命名空间 //insertStudent 在此命名空间下有个id为insertStudent的mapper session.insert("me.mxzf.mapping.StudentMapper.insertStudent", student); session.commit(); } catch (Exception e) { session.rollback(); } finally { session.close(); } 在总配置文件中配置Bean别名(properties?,settings?,typeAliases?,typeHandlers?,objectFactory?,objectWrapperFactory?,plugins?,environments?,databaseIdProvider?,mappers?) <typeAliases> <!-- 自动扫描包下的Bean --> <package name="me.mxzf.domain"/> <typeAlias type="me.mxzf.domain.Student" alias="Student"/> </typeAliases>

7、通过接口和java注解的方式

//接口 public interface StudentDAO { @Select("select * from student where sid=#{sid}") public Student selectStudentById(int sid); }

Mybatis注解学习 – xxxMapper is not known to the MapperRegistry

Mybatis注解一定要注册自己写的接口类，不然就会老报开头提到的这个错误

1、factory.getConfiguration().addMapper(UserInfoMapper.class);//动态注册

2、 //静态注册

3、演示CRUD操作

1、UserMapper接口文件 public interface UserMapper { @Insert("insert into users(name, age) values(#{name}, #{age})") public int add(Users user); @Delete("delete from users where id = #{id}") public int deleteById(int id); @Update("update users set name = #{name}, age = #{age} where id = #{id}") public int update(Users user); @Select("select * from users where id = #{id}") public Users getUserById(int id); @Select("select * from users") public List<Users> getAllUsers(); } 2、在总配置文件mappers中注册UserMapper这个接口 <mapper class="com.bird.mybatis.bean.UserMapper"/> 3、使用这个类 SqlSession openSession = factory.openSession(); UserMapper mapper = openSession.getMapper(UserMapper.class); //动态注入到接口中 mapper.add(new Users(-1,"娃娃",99)); //提交修改 openSession.commit(); openSession.close();