Mybaits入门

Mybaits入门

一、先配置主配置文件xml（mybaits-config.xml）

导入mybatis包（这里会链接MySQL数据库所以MySQL包也得导入）

注意：这里创建的实例是java项目

<?xml version="1.0" encoding="UTF-8" ?>
<!-- 约束 -->
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">

  <configuration>
      <!-- 导入properties 文件 -->
      <properties resource="db.properties"></properties>
      
        <!--环境配置(链接数据库) -->
      <environments default="development">
           <environment id="development">
               <!-- 事务控制 -->
               <transactionManager type="JDBC" />
               <!-- 数据源 -->
               <dataSource type="POOLED">
                   <property name="driver" value="${driver}"/>
                   <property name="url" value="${url}"/>
                   <property name="username" value="${username}"/>
                   <property name="password" value="${password}"/>
               </dataSource>
           </environment>
      </environments>
      
      <!-- 引入映射文件 -->
      
      <mappers>
          <mapper resource="mybatis-student.xml"/>
      </mappers>
  </configuration>

二、建立properties联系数据源

driver=com.mysql.jdbc.Driver
url=jdbc:mysql:///bj
username=root
password=123456

三、配置映射文件（mybatis-student.xml）(增删改查在这里进行)

<?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="student">
    <insert id="addstudent" parameterType="org.laogao.pojo.student">
        insert into student values(#{id},#{name},#{age},#{sex});
    </insert>
    
    <delete id="delete" parameterType="org.laogao.pojo.student">
        delete from  student where id=#{id}
    </delete>
  
  <update id="updatestudent" parameterType="org.laogao.pojo.student">
      update student set name=#{name},age=#{age},sex=#{sex} where id=#{id}
  
  
  </update>
  
  <select id="showstudent"  resultType="org.laogao.pojo.student">
  
      select * from student 
  </select>
  
  <select id="showstudentone" resultType="org.laogao.pojo.student" parameterType="org.laogao.pojo.student">
  
  select * from student where id=#{id}
  
  </select>
</mapper>

四、建立测试类（这种公司里基本不用，但利于新手理解，了解即可）

常用类型请看mybaits进阶

public class TestMybatis  {
    @Test
 //写法用的是JUNIT
    public void addstudent() throws IOException{
        //解析主配置文件成一个输入流
        InputStream stream = Resources.getResourceAsStream("mybaits-config.xml");
        //sqlsession工厂
        //通过SqlSessionFactoryBuilder.build(stream)构建实例获得SqlSessionFactory
        SqlSessionFactory SqlSessionFactory = new SqlSessionFactoryBuilder().build(stream);
        
        //生成sql
        SqlSession session = SqlSessionFactory.openSession();
        //写一条数据
        student student = new student(0, "hp", "12", "nv");
        //增加
        session.insert("student.addstudent", student);
        session.commit();
    }
 
 
    @Test
    public void deletestudentbyid() throws Exception{
        //解析主配置文件成一个输入流
        InputStream stream = Resources.getResourceAsStream("mybaits-config.xml");
        SqlSessionFactory SqlSessionFactory = new SqlSessionFactoryBuilder().build(stream);
        
        SqlSession session = SqlSessionFactory.openSession();
        
        session.delete("student.delete", 22);
        session.commit();
    }
    @Test
    public void updatestudentnyid() throws Exception{
        InputStream stream = Resources.getResourceAsStream("mybaits-config.xml");
        
        SqlSessionFactory SqlSessionFactory = new SqlSessionFactoryBuilder().build(stream);
        
        SqlSession session = SqlSessionFactory.openSession();
        
        student student = new student(15, "sb", "20", "s");
        session.update("student.updatestudent", student);
        session.commit();
    }
    
    @Test
    public void showstudent() throws Exception{
        InputStream stream = Resources.getResourceAsStream("mybaits-config.xml");
        
        SqlSessionFactory SqlSessionFactory = new SqlSessionFactoryBuilder().build(stream);
        
        SqlSession session = SqlSessionFactory.openSession();
        List<student> studentlist=session.selectList("student.showstudent",null);
        for (student student : studentlist) {
            System.out.println(student.toString());
            
        }
        
    }
    
    
    
    @Test
    public void showstudentone() throws Exception{
        InputStream stream = Resources.getResourceAsStream("mybaits-config.xml");
        
        SqlSessionFactory  SqlSessionFactory= new SqlSessionFactoryBuilder().build(stream);
        
        SqlSession session = SqlSessionFactory.openSession();
        
        
        Object student = session.selectOne("student.showstudentone", 15);
        System.out.println(student.toString());
    }
}