mybatis快速入门--根据配置文件执行SQL语句
MyBatis 是一个可以自定义SQL、存储过程和高级映射的持久层框架。使用的开发工具是Eclipse+mybatis-3.3.0-SNAPSHOT.jar+mysql-connector-java-5.1.7-bin.jar+mysql
下载mybatis-3.3.0-SNAPSHOT.jar网址：https://github.com/mybatis/mybatis-3/releases
创建工程：
在MySQL创建Test数据库：create database Test;
在Test中创建student表： CREATE TABLE `student` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`username` varchar(20) DEFAULT NULL,
`age` int(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
插入数据：insert into student(username,age)values('admin',20);
mybatis的重要配置文件，
<?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>
<typeAliases>
<!--给实体类起一个别名 user -->
<typeAlias type="com.lcb.domain.User" alias="User" />
</typeAliases>
<!--数据源配置 这块用 mysql数据库 -->
<environments default="development">
<environment id="development">
<transactionManager type="jdbc" />
<dataSource type="POOLED">
<!-- 加载jdbc驱动-->
<property name="driver" value="com.mysql.jdbc.Driver" />
<!-- MySQL URL-->
<property name="url" value="jdbc:mysql://localhost:3306/test" />
<!-- MySQL用户名-->
<property name="username" value="root" />
<!-- MySQL密码-->
<property name="password" value="" />
</dataSource>
</environment>
</environments>
<mappers>
<!--user.xml装载进来 同等于把“dao”的实现装载进来 -->
<mapper resource="com/lcb/mybatis/user.xml" />
</mappers>
</configuration>
创建User实体
public class User {
private int id;
private String username;
private int age;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
mybatis需要的sql语句配置文件
<?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">
<mapper namespace="com.lcb.domain.User">
<!-- selectOneId必须和接口中的方法名一样 返回一个resultType=User(要么是configuration.xml配置中起的别名或者是包名+实体类名)-->
<select id="selectOneId" parameterType="HashMap" resultType="User">
select
* from student where id=#{id}
</select>
</mapper>
mybatis测试
public class MybatisTest {
private static SqlSessionFactory sqlSessionFactory = null;
private static SqlSession sqlSession = null;
static{
try {
//根据配置文件获取SqlSessionFactory
sqlSessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader("configuration.xml"));
//根据SqlSessionFactory获取SqlSession
sqlSession = sqlSessionFactory.openSession();
} catch (IOException e) {
e.printStackTrace();
}
}
private static SqlSessionFactory getSqlSessionFactory(){
return sqlSessionFactory;
}
private static SqlSession getSqlSession(){
return sqlSession;
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
//SqlSession sqlSession = getSessionFactory().openSession();
//UserMapp userMapper = sqlSession.getMapper(UserMapper.class);
//selectOne("namespace+id", "需要的参数值")
User user = sqlSession.selectOne("com.lcb.domain.User.selectOneId", 14);
System.out.println(user.getUsername());
}
}
//输出结果
admin
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