Mapper通过实现接口进行增加和查看操作

首先，为了避免打开sql会话的准备工作多次进行，采用静态方法，对准备工作静态初始化，创建一个BaseDAO类：

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package com.dao;

import java.io.IOException;
import java.io.InputStream;

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 BaseDAO {
                   static final String CONFIG_FILE = "mybaits-config.xml";
                   static SqlSessionFactory sqlSessionFactory;
                   static SqlSession session;
                   static {
                           try {
                               InputStream inputStream = Resources.getResourceAsStream(CONFIG_FILE);
                               // sqlSessionFactory是写在全局，否则静态代码块中不能使用，即静态方法中也不能用
                               sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
                           } catch (IOException e) {
                               // TODO Auto-generated catch block
                               e.printStackTrace();
                           }
                   }

                   public static SqlSession getSession() {
                       return session = sqlSessionFactory.openSession();
                   }

}

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然后，着手准备实体类这里我准备的是Teacher，代码如下：

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package com.entity;

public class Teacher {
           private int teaId;
           private String teaName;
           private int teaAge;
           public int getTeaId() {
               return teaId;
           }
           public void setTeaId(int teaId) {
               this.teaId = teaId;
           }
           public String getTeaName() {
               return teaName;
           }
           public void setTeaName(String teaName) {
               this.teaName = teaName;
           }
           public int getTeaAge() {
               return teaAge;
           }
           public void setTeaAge(int teaAge) {
               this.teaAge = teaAge;
           }
           @Override
           public String toString() {
               return "Teacher [teaId=" + teaId + ", teaName=" + teaName + ", teaAge=" + teaAge + "]";
           }
}

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然后，着手准备接口,这里我准备的是TeacherDAO接口，方法有增加和查找，代码如下

---------------------------------------------代码开始---------------------------------------------

package com.dao;

import java.util.List;

import org.apache.ibatis.annotations.Param;

import com.entity.Teacher;

public interface TeacherDAO {
   //这里的注解必须存在，它帮助mapper映射文件识别
   //如果是单个基本类型则不用写注解，多个基本类型也要写
       public void add(@Param("tea") Teacher tea);
       public List<Teacher> findAll();
}

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然后，写Mapper映射文件，我这里写的是TeacherMapper.xml，代码如下：

---------------------------------------------代码开始---------------------------------------------

<?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="com.dao.TeacherDAO">

           <insert id="add">
                          insert into teacher values(null,#{tea.teaName},#{tea.teaAge})
           </insert>
           
           <select id="findAll" resultType="com.entity.Teacher">
                          select * from teacher
           </select>
</mapper>

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然后，可以测试了，这里直接在main方法中测试，代码如下：

增加测试：

---------------------------------------------代码开始---------------------------------------------

package com.test;

import org.apache.ibatis.session.SqlSession;

import com.dao.BaseDAO;
import com.dao.TeacherDAO;
import com.entity.Teacher;

public class test {
           public static void main(String[] args) {
                       SqlSession session;
                       Teacher teacher=new Teacher();
                       teacher.setTeaName("李四");
                       teacher.setTeaAge(12);
                       session=BaseDAO.getSession();
                       //TeacherDAO是一个接口，实现类只能通过会话的方法获得
                       TeacherDAO dao=session.getMapper(TeacherDAO.class);
                       dao.add(teacher);
                       session.commit();
                       session.close();
           }
}

---------------------------------------------代码结束---------------------------------------------

查看测试：

---------------------------------------------代码开始---------------------------------------------

package com.test;

import java.util.List;

import org.apache.ibatis.session.SqlSession;

import com.dao.BaseDAO;
import com.dao.TeacherDAO;
import com.entity.Teacher;

public class test2 {
   public static void main(String[] args) {
       SqlSession session;
       session=BaseDAO.getSession();
       //TeacherDAO是一个接口，实现类只能通过会话的方法获得
       TeacherDAO dao=session.getMapper(TeacherDAO.class);
       List<Teacher> list=dao.findAll();
       for(Teacher tea: list){
           System.out.println(tea);
       }
       session.close();
}
}

---------------------------------------------代码结束---------------------------------------------

至此，完成。

Mapper通过实现接口进行增加和查看操作

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