标签：style blog http ar io color os 使用 sp
Mybatis入门第一节
MyBatis是支持普通的sql查询的，存储过程和高级映射的优秀的持久层框架，mybatis消除了几乎所有的jdbc代码和参数的手工的设置以及对结果集的检索封装，它可以使用简单的xml或者注解来配置和原始的映射，将接口和Java的pojo映射成数据库中的记录。
jdbc->dbutils(特点自动封装结果集)->MyBatis->Hibernate(基本不用写sql语句)
Hibernate可以直接跟数据库连接，MyBaties需要一个中间层（配置文件xml）来跟数据库有关系。
1：首先导入mybatis的架包mybatis-3.1.1.jar.
2：创建数据库和表
CREATE DATABASE mybatis; USE mybatis; CREATE TABLE users( id INT PRIMARY KEY AUTO_INCREMENT, NAME VARCHAR(20), age INT ); INSERT INTO users(NAME,age) VALUES (‘tom‘,12); INSERT INTO users(NAME,age) VALUES (‘jack‘,11);
3：添加mybatis的配置文件conf.xml
<?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="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="root" /> </dataSource> </environment> </environments> </configuration>
4:定义表所对应的实体类
package bean; public class User { private int id; private String name; private int age; 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 int getAge() { return age; } public void setAge(int age) { this.age = age; } }
5：定义操作users表的sql映射文件userMapper.xml
<?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="bean.userMapper"> <!-- 根据id查询得到一个user对象 --> <select id="getUser" parameterType="int" resultType="bean.User"> select * from users where id=#{id} </select> </mapper>
6:在config.xml文件中注册userMapper.xml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> <properties resource="db.properties"/> <!-- development : 开发模式 work : 工作模式 --> <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="${name}" /> <property name="password" value="${password}" /> </dataSource> </environment> </environments> <mappers> <mapper resource="bean/userMapper.xml"/> </mappers> </configuration>
7：编写测试类
package Test; import java.io.IOException; import java.io.Reader; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import bean.User; public class Test { public static void main(String[] args) throws IOException { String resource = "conf.xml"; //加载mybatis的配置文件（它也加载关联的映射文件） Reader reader = Resources.getResourceAsReader(resource); //构建sqlSession的工厂 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader); //创建能执行映射文件中sql的sqlSession SqlSession session = sessionFactory.openSession(); //映射sql的标识字符串 String statement = "bean.userMapper"+".getUser"; //执行查询返回一个唯一user对象的sql User user = (User)session.selectOne(statement,1); //User user = session.selectOne(statement, 1); System.out.println(user.getName()); } }
标签：style blog http ar io color os 使用 sp
原文地址：http://www.cnblogs.com/aicpcode/p/4169058.html
