编写Mybatis代码,与spring不一样,不需要导入插件,只需导入架包即可;
在lib下 导入mybatis架包:mybatis-3.1.1.jar
mysql驱动架包:mysql-connector-java-5.1.6-bin.jar
在src目录下建立xml配置文件:conf.xml,是一些连接数据库的配置:
<?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:开发模式 work:工作模式 default="development",id="development",两个的属性值必须一致 --> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/> <property name="username" value="root"/> <property name="password" value="lxn123"/> </dataSource> </environment> </environments> <!-- 在配置文件中 关联包下的 接口类--> <mappers> <mapper class="com.atguigu.mybatis.test3.UserMapper"/> </mappers> </configuration>
这是基于注解的方式,所以建立一个接口,在定义的方法上配置上应有的注解,注解中含有sql语句,需要提示的是这个接口不需要类去实现它
package com.atguigu.mybatis.test3; import java.util.List; import org.apache.ibatis.annotations.Delete; import org.apache.ibatis.annotations.Insert; import org.apache.ibatis.annotations.Select; import org.apache.ibatis.annotations.Update; import com.atguigu.mybatis.test.User; public interface UserMapper { /* * 这是基于注解的映射方式,实现对数据的增删改查,将sql语句直接写在注解的括号中 * 这是一个接口,其不需要类去实现它 * 下边分别是插入,删除,修改,查询一个记录,查询所有的记录 * */ @Insert("insert into users(name,age) values(#{name},#{age})") public void insertT(User user); @Delete("delete from users where id=#{id}") public void deleteById(int id); @Update("update users set name=#{name},age=#{age} where id=#{id}") public void updateT(User user); @Select("select * from users where id=#{id}") public User getUser(int id); @Select("select * from users") public List<User> getAllUsers(); }
封装列:User,这儿只写属性,getter和setter,tostring就不写了
private int id; private String name; private int age;
建立MybatisUtils类,有一个方法,加载mybatis和构建sqlSession
package com.atguigu.mybatis.test; import java.io.InputStream; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class MybatisUtils { public static SqlSessionFactory getFactory(){ String resource="conf.xml"; //加载mybatis 的配置文件(它也加载关联的映射文件) InputStream is=MybatisUtils.class.getClassLoader().getResourceAsStream(resource); //构建sqlSession 的工厂 SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is); return factory; } }
实现增删改查的方法
package com.atguigu.mybatis.test3; import java.util.List; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.junit.Test; import com.atguigu.mybatis.test.MybatisUtils; import com.atguigu.mybatis.test.User; public class UserMapperTest { @Test //插入数据 public void testInsert(){ SqlSessionFactory factory=MybatisUtils.getFactory(); SqlSession session=factory.openSession(true); //使用反射的方法 UserMapper mapper=session.getMapper(UserMapper.class); mapper.insertT(new User(-1, "p", 4)); session.close(); } @Test //删除数据 public void testDelete(){ SqlSessionFactory factory=MybatisUtils.getFactory(); SqlSession session=factory.openSession(true); UserMapper mapper=session.getMapper(UserMapper.class); mapper.deleteById(1); session.close(); } @Test //修改数据 public void testUpdate(){ SqlSessionFactory factory=MybatisUtils.getFactory(); SqlSession session=factory.openSession(true); UserMapper mapper=session.getMapper(UserMapper.class); mapper.updateT(new User(2, "jjjjj", 232)); session.close(); } @Test //获取一条数据 public void testGetUser(){ SqlSessionFactory factory=MybatisUtils.getFactory(); SqlSession session=factory.openSession(true); UserMapper mapper=session.getMapper(UserMapper.class); User user=mapper.getUser(2); session.close(); System.out.println(user); } @Test //获取所有数据 public void testGetAllUsers(){ SqlSessionFactory factory=MybatisUtils.getFactory(); SqlSession session=factory.openSession(true); UserMapper mapper=session.getMapper(UserMapper.class); List<User> users=mapper.getAllUsers(); session.close(); System.out.println(users); } }