Mybatis的简单示例

 1 public class User {
 2     private String username;
 3     private String password;
 4     private int age;
 5     public String getUsername() {
 6         return username;
 7     }
 8     public void setUsername(String username) {
 9         this.username = username;
10     }
11     public String getPassword() {
12         return password;
13     }
14     public void setPassword(String password) {
15         this.password = password;
16     }
17     public int getAge() {
18         return age;
19     }
20     public void setAge(int age) {
21         this.age = age;
22     }
23 }

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 3 <!-- 为这个mapper指定一个唯一的namespace，namespace的值习惯上设置成包名+sql映射文件名)
 4  -->
 5 <mapper namespace="com.mybatis.mapping.userMapper">
 6     <!-- 在select标签中编写查询的SQL语句,id属性值必须是唯一的
 7     使用parameterType属性指明查询时使用的参数类型，resultType属性指明查询返回的结果集类型
 8     -->
 9     <!-- 
10         根据username查询得到一个user对象
11      -->
12     <select id="getUser" parameterType="java.lang.String" 
13         resultType="com.mybatis.po.User">
14         select * from user where username=#{username}
15     </select>
16     
17        <delete id="deleteUser" parameterType="java.lang.String">
18         delete from user where username=#{username}
19     </delete>
20 </mapper>

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
 3 <configuration>
 4     <environments default="development">
 5         <environment id="development">
 6             <transactionManager type="JDBC" />
 7             <!-- 配置数据库连接信息 -->
 8             <dataSource type="POOLED">
 9                 <property name="driver" value="com.mysql.jdbc.Driver" />
10                 <property name="url" value="jdbc:mysql://localhost:3306/test" />
11                 <property name="username" value="root" />
12                 <property name="password" value="" />
13             </dataSource>
14         </environment>
15     </environments>
16      <mappers>
17         <!-- 注册userMapper.xml文件，resource为userMapper.xml所在目录-->
18          <mapper resource="com/mybatis/mapping/userMapper.xml"/>
19      </mappers>
20 </configuration>

 1 public class Test {
 2 
 3     public static void main(String[] args) throws IOException {
 4         //mybatis的配置文件
 5         String resource = "config.xml";
 6         //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）
 7         InputStream is = Test.class.getClassLoader().getResourceAsStream(resource);
 8         //构建sqlSession的工厂
 9         SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(is);
10         //打开session
11         SqlSession session = sessionFactory.openSession();
12         /**
13          * 映射sql的标识字符串
14          *com.mybatis.mapping.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，
15          * getUser是select标签的id属性值，通过select标签的id属性值就可以找到要执行的SQL
16          */
17         String statement = "com.mybatis.mapping.userMapper.getUser";//映射sql的标识字符串
18         //执行查询返回一个唯一user对象的sql
19         User user = session.selectOne(statement,"username1");
20         System.out.println(user.getUsername());
21         String statement2="com.mybatis.mapping.userMapper.deleteUser";
22         session.delete(statement2,user);
23     }
24 }