工程结构如下
1、引入jar mybatis-3.2.3.jar 和mysql-connector-java-5.1.25.bin.jar
2、使用Mysql创建表
CREATE TABLE `user` ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `name` VARCHAR(64) NOT NULL DEFAULT '', `dept` VARCHAR(254) NOT NULL DEFAULT '', `website` VARCHAR(254) DEFAULT '', `phone` VARCHAR(16) NOT NULL DEFAULT '', PRIMARY KEY (`id`) ) ENGINE=INNODB AUTO_INCREMENT=2 ; INSERT INTO `user` VALUES ('1', 'larry', 'IT', 'http://www.baidu.com', '13688889999');
3、创建User实体类
public class User { private int id; private String name; private String dept; private String phone; private String website; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getDept() { return dept; } public void setDept(String dept) { this.dept = dept; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } public String getWebsite() { return website; } public void setWebsite(String website) { this.website = website; } }
4、resources/configs/下创建Configure.xml
mybatis 配置文件,用来建立sessionFactory。里面主要包含了数据库连接,还有Java类对应的别名
<?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 alias="User2" type="com.example.mybatis.model.User" /> </typeAliases> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"></transactionManager> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis"/> <property name="username" value="root"/> <property name="password" value="123456"/> </dataSource> </environment> </environments> <mappers> <mapper resource="mapper/User.xml" /> </mappers> </configuration>
这里<mapper resource="mapper/User.xml" /> 要映射类的xml配置文件
5、resources/mapper下创建User.xml
包含了各种SQL语句
<?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.example.mybatis.dao.UserMapper"> <select id="getUserById" parameterType="int" resultType="User2"> select * from user where id = #{id} </select> </mapper>
6、创建接口com.example.mybatis.dao.UserMapper
public interface UserMapper { User getUserById(int id); }
7、创建测试类
public class MyBatisTest1 { private static SqlSessionFactory sqlSessionFactory; private static Reader reader; static { try { reader = Resources.getResourceAsReader("config/Configure.xml"); sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); }catch (Exception e){ e.printStackTrace(); } } public static SqlSessionFactory getSession(){ return sqlSessionFactory; } public static void main(String[] args) { SqlSession session = sqlSessionFactory.openSession(); try { User user = (User)session.selectOne("com.example.mybatis.dao.UserMapper.getUserById",1 ) ; if(user != null){ System.out.println("name is : " + user.getName() + ",所属部门: " + user.getDept()); } }finally { session.close(); } } }
8、显示