MyBatis 实现增删改查-蒲公英云

今天来实现 mybatis 最基本的增删改查操作：

依旧是三步：1.config.xml 配置文件 2. mapper.xml 映射配置文件 3.测试

首先1.config.xml 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>
<!--开发环境 (自己的计算机)  -->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <!--POOLED：使用连接池 避免打开和关闭数据库的耗时  -->
            <dataSource type="POOLED">
            <!-- 配置数据库信息 -->
                <property name="driver" value="oracle.jdbc.OracleDriver" />
                <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl" />
                <property name="username" value="sys as sysdba" />
                <property name="password" value="123456" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
    <!-- 加载映射 文件 -->
        <mapper resource="org/cjr/entity/PersonMapper.xml" />
    </mappers>
</configuration>

这个配置文件是固定写法，大部分Mybatis的配置都是这样的。

接下来写映射文件：

<?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="org.cjr.entity.PersonMapper">
    <select id="queryPersonById" resultType="org.cjr.entity.Person" parameterType="int">
        select * from Person where id = #{id}
    </select>
    <select id="queryAll" resultType="org.cjr.entity.Person">
        select * from Person 
    </select>
    <insert id="addPerson" parameterType="org.cjr.entity.Person">
    insert into person values(#{id},#{name},#{age})
    </insert>
    <delete id="deletePerson" parameterType="int">
    delete from person where id= #{id}
    </delete>
    <update id="updatePerson" parameterType="org.cjr.entity.Person">
    update person set name=#{name},age=#{age} where id=#{id}
    </update>
</mapper>

该映射文件存放了Sql语句以及返回值类型等信息。

最后我们写测试类

package org.cjr.entity;
import java.io.IOException;
import java.io.Reader;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
public class testMyBatis {
   public static void queryStudentBySno() throws IOException {
       //加载配置文件
          Reader reader = Resources.getResourceAsReader("config.xml");
           //qlSessionFactory 
          SqlSessionFactory sqlSessionFactory = new  SqlSessionFactoryBuilder().build(reader);
          //session- 相当于connection
          SqlSession session = sqlSessionFactory.openSession();
          //映射文件中的namespace + id
         Person person = session.selectOne("org.cjr.entity.PersonMapper.queryPersonById",1);
       //   Person person = (Person) session.selectOne("org.cjr.entity.PersonMapper.queryAll");
          System.err.println(person);
          session.close();
   }
   //查询
   public static void queryAllStudent() throws IOException {
       //加载配置文件
          Reader reader = Resources.getResourceAsReader("config.xml");
           //qlSessionFactory 
          SqlSessionFactory sqlSessionFactory = new  SqlSessionFactoryBuilder().build(reader);
          //session- 相当于connection
          SqlSession session = sqlSessionFactory.openSession();
          //映射文件中的namespace + id
         List<Person> persons = session.selectList("org.cjr.entity.PersonMapper.queryAll");
          System.err.println(persons);
          session.close();
   }
   //增加
   public static void addStudent() throws IOException {
       //加载配置文件
          Reader reader = Resources.getResourceAsReader("config.xml");
           //qlSessionFactory 
          SqlSessionFactory sqlSessionFactory = new  SqlSessionFactoryBuilder().build(reader);
          //session- 相当于connection
          SqlSession session = sqlSessionFactory.openSession();
          //映射文件中的namespace + id
        Person person = new Person(3,"ww",30); 
    int count =  session.insert("org.cjr.entity.PersonMapper.addPerson",person);
         session.commit();//提交事务
    System.out.println("增加"+count+"个学生");
          session.close();
   }
   //删除
   public static void deleteStudent() throws IOException {
       //加载配置文件
          Reader reader = Resources.getResourceAsReader("config.xml");
           //qlSessionFactory 
          SqlSessionFactory sqlSessionFactory = new  SqlSessionFactoryBuilder().build(reader);
          //session- 相当于connection
          SqlSession session = sqlSessionFactory.openSession();
          //映射文件中的namespace + id  
    int count =  session.delete("org.cjr.entity.PersonMapper.deletePerson",3);
         session.commit();//提交事务
    System.out.println("删除"+count+"个学生");
          session.close();
   }
 //改
   public static void updateStudent() throws IOException {
       //加载配置文件
          Reader reader = Resources.getResourceAsReader("config.xml");
           //qlSessionFactory 
          SqlSessionFactory sqlSessionFactory = new  SqlSessionFactoryBuilder().build(reader);
          //session- 相当于connection
          SqlSession session = sqlSessionFactory.openSession();
          //映射文件中的namespace + id  
          Person person = new Person();
          person.setId(2);
          person.setName("zzz");
          person.setAge(99);
    int count =  session.update("org.cjr.entity.PersonMapper.updatePerson",person);
         session.commit();//提交事务
    System.out.println("修改"+count+"个学生");
          session.close();
   }
   public static void main(String[] args) throws IOException {
       //deleteStudent();
       //updateStudent();
       //addStudent();
       queryAllStudent();
   }
}