Java Mybatis框架入门基础教程

package .oumyye.model;

public class User {
  private String id;
  private String name;
  private int age;
  public String getId() {
    return id;
  }
  public void setId(String 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 + "]";
  }

}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.//DTD Mapper 3.0//EN" "http://mybatis./dtd/mybatis-3-mapper.dtd">

<mapper namespace=".oumyye.mapping.UserMapping">
  <!-- 在select标签中编写查询的SQL语句， 设置select标签的id属性为getUser，id属性值必须是唯一的，不能够重复
  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
  resultType=".oumyye.model.User"就表示将查询结果封装成一个User类的对象返回
  User类就是users表所对应的实体类
  -->
  <!-- 
    根据id查询得到一个user对象
   -->
  <select id="getUser" parameterType="String" 
    resultType=".oumyye.model.User">
    select * from user where id=#{id}
  </select>
</mapper>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.//DTD Config 3.0//EN" "http://mybatis./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=".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>
  <mappers>

<mapper resource="/oumyye/mapping/userMapping.xml"/>
   </mappers>
</configuration>

package test;

import java.io.InputStream;

import .apache.ibatis.session.SqlSession;
import .apache.ibatis.session.SqlSessionFactory;
import .apache.ibatis.session.SqlSessionFactoryBuilder;
import .junit.Test;

import .oumyye.model.User;

public class Tests {
@Test
public void test(){
 String resource = "mybatis.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 = Tests.class.getClassLoader().getResourceAsStream(resource);
    //构建sqlSession的工厂
    SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(is);

SqlSession session = sessionFactory.openSession();
    /**
     * 映射sql的标识字符串，
     * .oumyye.mapping.UserMapping是userMapper.xml文件中mapper标签的namespace属性的值，
     * 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
     */
    String statement = ".oumyye.mapping.UserMapping.getUser";//映射sql的标识字符串
    //执行查询返回一个唯一user对象的sql
    User user = session.selectOne(statement, "1123");
    System.out.println(user.toString());
}
}