做了个mybatis的Demo，发现mybatis和我之前实习时用的EOS开发工具中的对数据库操作的组件很类似，现在想来那个EOS就是对mybatis进行了封装。
eclipse下的Demo
数据库表
与数据表映射的实体类
//与数据表映射的实体类
package dao;
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;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
}
}
userMapper.xml
<!--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="mapping.userMapper">
<!-- parameterType为传入参数类型，resultType为结果返回接收的类型 -->
<select id="getUser" parameterType="int"
resultType="dao.User">
select * from users
</select>
</mapper>
mybatis配置文件
<!-- mybatis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>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<!-- 配置数据库连接信息 -->
<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="000000" />
</dataSource>
</environment>
</environments>
<mappers>
<!-- 注册userMapper.xml文件 -->
<mapper resource="mapping/userMapper.xml"/>
</mappers>
</configuration>
测试类
public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
//mybatis的配置文件
String resource = "conf.xml";
//使用类加载器加载mybatis的配置文件（它也加载关联的映射文件）
InputStream is = Test.class.getClassLoader().getResourceAsStream(resource);
//构建sqlSession的工厂
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(is);
//使用MyBatis提供的Resources类加载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();
String statement = "mapping.userMapper.getUser";//映射sql的标识字符串
List<User> userList = session.selectList(statement);
for(int i = 0;i<userList.size();i++){
System.out.println(userList.get(i).toString());
}
}
}
以上输出结果是user表的所有内容。
mapper.xml的sql语句中可以随意的设置parameterType传入参数，是基本类型也可以是自定义的类，查询结果接收类型resultType也可以随便设置只要sql查询出的结果的属性能够满足是resultType属性的子集就可以（sql结果的属性name在resultType中都能有与之相对应的name）。
//mapper中设置
<mapper namespace="mapping.userMapper">
<select id="getUser" parameterType="dao.User"
resultType="dao.User">
select * from users where id=#{id} and name = #{name}
</select>
</mapper>
//java中调用
User user = new User();
user.setAge(1);
user.setId(1);
user.setName("johnny");
// HashMap<String, Object> map = new HashMap<String, Object>();
// map.put("id", 2);
// map.put("name", "asd");
List<User> userList = session.selectList(statement, user);
for(int i = 0;i<userList.size();i++){
System.out.println(userList.get(i).toString());
}
