mybatis原生dao实现和动态代理Dao实现

原生dao
dao接口

package cn.itheima.dao;

import java.util.List;

import cn.itheima.pojo.User;

public interface UserDao {

    public User findUserById(Integer id);

    public List<User> findUserByUserName(String userName);
}

dao实现

package cn.itheima.dao;

import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import cn.itheima.pojo.User;

public class UserDaoImpl implements UserDao {

    private SqlSessionFactory sqlSessionFactory;

    //通过构造方法注入
    public UserDaoImpl(SqlSessionFactory sqlSessionFactory) {
        this.sqlSessionFactory = sqlSessionFactory;
    }

    @Override
    public User findUserById(Integer id) {
        //sqlSesion是线程不安全的,所以它的最佳使用范围在方法体内
        SqlSession openSession = sqlSessionFactory.openSession();
        User user = openSession.selectOne("test.findUserById", id);
        return user;
    }

    @Override
    public List<User> findUserByUserName(String userName) {
        SqlSession openSession = sqlSessionFactory.openSession();
        List<User> list = openSession.selectList("test.findUserByUserName", userName);
        return list;
    }


}

测试原生dao

package mybatis0523;

import java.io.InputStream;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;

import cn.itheima.dao.UserDao;
import cn.itheima.dao.UserDaoImpl;
import cn.itheima.pojo.User;

public class UserDaoTest {

    private SqlSessionFactory factory;

    //作用:在测试方法前执行这个方法
    @Before
    public void setUp() throws Exception{
        String resource = "SqlMapConfig.xml";
        //通过流将核心配置文件读取进来
        InputStream inputStream = Resources.getResourceAsStream(resource);
        //通过核心配置文件输入流来创建会话工厂
        factory = new SqlSessionFactoryBuilder().build(inputStream);
    }

    @Test
    public void testFindUserById() throws Exception{
        //将初始化好的工厂注入到实现类中
        UserDao userDao = new UserDaoImpl(factory);

        User user = userDao.findUserById(1);
        System.out.println(user);
    }

    @Test
    public void testFindUserByUserName () throws Exception{

        UserDao userDao = new UserDaoImpl(factory);

        List<User> list = userDao.findUserByUserName("王");
        System.out.println(list);
    }
}

mapper接口代理
XX.java和XX.xml在同一个文件夹下面，然后名字也要相同
这是使用class属性引入接口的全路径名称使用规则：
1.接口的名称和映射文件名称除扩展名外要完全相同
2.接口和映射文件要放在同一个目录下
XX.xml
mapper接口代理实现编写规则:

映射文件中namespace要等于接口的全路径名称
映射文件中sql语句id要等于接口的方法名称
映射文件中传入参数类型要等于接口方法的传入参数类型
映射文件中返回结果集类型要等于接口方法的返回值类型

<?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="cn.itheima.mapper.UserMapper">

    <!-- 
    id:sql语句唯一标识
    parameterType:指定传入参数类型
    resultType:返回结果集类型
    #{}占位符:起到占位作用,如果传入的是基本类型(string,long,double,int,boolean,float等),那么#{}中的变量名称可以随意写.
     -->
    <select id="findUserById" parameterType="int" resultType="cn.itheima.pojo.User">
        select * from user where id=#{id}
    </select>

    <!-- 
    如果返回结果为集合,可以调用selectList方法,这个方法返回的结果就是一个集合,所以映射文件中应该配置成集合泛型的类型
    ${}拼接符:字符串原样拼接,如果传入的参数是基本类型(string,long,double,int,boolean,float等),那么${}中的变量名称必须是value
    注意:拼接符有sql注入的风险,所以慎重使用
     -->
    <select id="findUserByUserName" parameterType="string" resultType="user">
        select * from user where username like '%${value}%'
    </select>

    <!-- 
    #{}:如果传入的是pojo类型,那么#{}中的变量名称必须是pojo中对应的属性.属性.属性.....
    如果要返回数据库自增主键:可以使用select LAST_INSERT_ID()
     -->
    <insert id="insertUser" parameterType="cn.itheima.pojo.User" >
        <!-- 执行 select LAST_INSERT_ID()数据库函数,返回自增的主键
        keyProperty:将返回的主键放入传入参数的Id中保存.
        order:当前函数相对于insert语句的执行顺序,在insert前执行是before,在insert后执行是AFTER
        resultType:id的类型,也就是keyproperties中属性的类型
        -->
        <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
            select LAST_INSERT_ID()
        </selectKey>
        insert into user (username,birthday,sex,address) values(#{username},#{birthday},#{sex},#{address})
    </insert>
</mapper>

XX.java

package cn.itheima.mapper;

import java.util.List;

import cn.itheima.pojo.User;

public interface UserMapper {

    public User findUserById(Integer id);

    //动态代理形势中,如果返回结果集问List,那么mybatis会在生成实现类的使用会自动调用selectList方法
    public List<User> findUserByUserName(String userName);

    public void insertUser(User user);
}

XXTest.java

package mybatis0523;

import java.io.InputStream;
import java.util.Date;
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;
import org.junit.Before;
import org.junit.Test;

import cn.itheima.mapper.UserMapper;
import cn.itheima.pojo.User;

public class UserMapperTest {
    private SqlSessionFactory factory;

    //作用:在测试方法前执行这个方法
    @Before
    public void setUp() throws Exception{
        String resource = "SqlMapConfig.xml";
        //通过流将核心配置文件读取进来
        InputStream inputStream = Resources.getResourceAsStream(resource);
        //通过核心配置文件输入流来创建会话工厂
        factory = new SqlSessionFactoryBuilder().build(inputStream);
    }

    @Test
    public void testFindUserById() throws Exception{
        SqlSession openSession = factory.openSession();
        //通过getMapper方法来实例化接口
        UserMapper mapper = openSession.getMapper(UserMapper.class);

        User user = mapper.findUserById(1);
        System.out.println(user);
    }

    @Test
    public void testFindUserByUserName() throws Exception{
        SqlSession openSession = factory.openSession();
        //通过getMapper方法来实例化接口
        UserMapper mapper = openSession.getMapper(UserMapper.class);

        List<User> list = mapper.findUserByUserName("王");

        System.out.println(list);
    }

    @Test
    public void testInsertUser() throws Exception{
        SqlSession openSession = factory.openSession();
        //通过getMapper方法来实例化接口
        UserMapper mapper = openSession.getMapper(UserMapper.class);

        User user = new User();
        user.setUsername("老王");
        user.setSex("1");
        user.setBirthday(new Date());
        user.setAddress("北京昌平");

        mapper.insertUser(user);

        openSession.commit();
    }
}

mybatis原生dao实现和动态代理Dao实现

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