Mybatis框架(六)：Mybatis的dao实现类方式的CRUD

一、环境的搭建

1、创建maven工程并导入坐标

2、创建实体类、持久层dao接口及dao的实现类

实体类

package com.wedu.mybatis06.domain;

import java.io.Serializable;
import java.util.Date;

/**
 * 用户实体
 */
public class User implements Serializable {

    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday=" + birthday +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

dao接口

package com.wedu.mybatis06.dao;

/**
 * 用户持久层接口
 */
public interface IUserDao {


}

dao接口实现类

package com.wedu.mybatis06.dao.impl;

import com.wedu.mybatis06.dao.IUserDao;
import org.apache.ibatis.session.SqlSessionFactory;

/**
 * dao接口实现类
 */
public class UserDaoImpl implements IUserDao {

    private SqlSessionFactory factory;

    public UserDaoImpl(SqlSessionFactory factory) {
        this.factory = factory;
    }

}

3、创建mybatis配置文件：SqlMapConfig.xml

<?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>
    <!--配置环境-->
    <environments default="mysql">
        <!--配置mysql的环境-->
        <environment id="mysql">
            <!--配置事务的类型-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置数据源-->
            <dataSource type="POOLED">
                <!-- 配置连接数据库的基本信息 -->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/test?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>

    <!--配置映射文件的位置-->
    <mappers>
        <mapper resource="com/wedu/mybatis06/dao/IUserDao.xml"/>
    </mappers>
</configuration>

4、创建映射文件：IUserDao.xml

<?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.wedu.mybatis06.dao.IUserDao">


</mapper>

5、创建测试类

package com.wedu.mybatis06.dao;

import com.wedu.mybatis06.dao.impl.UserDaoImpl;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;

import java.io.IOException;

/**
 * 基于dao实现类方式的CRUD操作的测试
 */
public class UserDaoTest {

    private IUserDao userDao;

    @Before
    public void init() throws IOException {
        //1.读取配置文件并创建SqlSessionFactory工厂
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("SqlMapConfig.xml"));
        userDao = new UserDaoImpl(factory);
    }
}

二、实现类方式的CRUD操作

1、添加操作

1.1、在IUserDao中添加保存方法

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    /**
     * 添加用户
     * @param user
     */
    void save(User user);

1.2、在IUserDao.xml中添加sql语句

    <!--添加用户-->
    <insert id="save" parameterType="com.wedu.mybatis06.domain.User">
        INSERT INTO USER (username,birthday,sex,address) VALUES (#{username},#{birthday},#{sex},#{address})
    </insert>

1.3、在UserDaoImpl实现类中实现方法

    /**
     * 添加用户
     * @param user
     */
    @Override
    public void save(User user) {
        //获取SqlSession对象
        SqlSession session = factory.openSession();
        //调用方法保存数据
        session.insert("com.wedu.mybatis06.dao.IUserDao.save", user);
        //提交事务
        session.commit();
        //释放资源
        session.close();
    }

1.4、在UserDaoTest中编写测试代码测试

    /**
     * 添加用户
     */
    @Test
    public void testSave() {
        User user = new User();
        user.setUsername("zhangsan");
        user.setBirthday(new Date());
        user.setSex("男");
        user.setAddress("上海");

        userDao.save(user);
    }

2、更新操作

2.1、在IUserDao中添加更新方法

    /**
     * 更新数据
     * @param user
     */
    void update(User user);

2.2、在IUserDao.xml中添加sql语句

    <!--根据id更新用户-->
    <update id="update" parameterType="com.wedu.mybatis06.domain.User">
        update user set username = #{username},birthday = #{birthday},sex = #{sex},address = #{address} where id = #{id}
    </update>

2.3、在UserDaoImpl实现类中实现方法

    /**
     * 更新用户
     * @param user
     */
    @Override
    public void update(User user) {
        SqlSession session = factory.openSession();
        session.update("com.wedu.mybatis06.dao.IUserDao.update",user);
        session.commit();
        session.close();
    }

2.4、在UserDaoTest中编写测试代码测试

    /**
     * 更新用户
     */
    @Test
    public void testUpdate() {
        User user = new User();
        user.setId(52);
        user.setUsername("lisi");
        user.setBirthday(new Date());
        user.setSex("女");
        user.setAddress("北京");

        userDao.update(user);
    }

3、查询操作

3.1、在IUserDao中添加查询方法

    /**
     * 根据id查询用户
     * @param id
     * @return
     */
    User findById(Integer id);

3.2、在IUserDao.xml中添加sql语句

    <!--根据id查询用户-->
    <select id="findById" parameterType="Integer" resultType="com.wedu.mybatis06.domain.User">
        select * from user where id = #{id}
    </select>

3.3、在UserDaoImpl实现类中实现方法

    /**
     * 根据id查询用户
     * @param id
     * @return
     */
    @Override
    public User findById(Integer id) {
        SqlSession session = factory.openSession();
        User user = session.selectOne("com.wedu.mybatis06.dao.IUserDao.findById", id);
        session.close();
        return user;
    }

3.4、在UserDaoTest中编写测试代码测试

    /**
     * 根据id查询用户
     */
    @Test
    public void testfindById() {
        User user = userDao.findById(52);
        System.out.println(user);
    }

4、删除操作

4.1、在IUserDao中添加删除方法

    /**
     * 删除数据
     * @param id
     */
    void delete(Integer id);

4.2、在IUserDao.xml中添加sql语句

    <!--删除用户-->
    <delete id="delete" parameterType="Integer">
        delete from user where id = #{id}
    </delete>

4.3、在UserDaoImpl实现类中实现方法

    /**
     * 根据id删除用户
     * @param id
     */
    @Override
    public void delete(Integer id) {
        SqlSession session = factory.openSession();
        session.delete("com.wedu.mybatis06.dao.IUserDao.delete",id);
        session.commit();
        session.close();
    }

4.4、在UserDaoTest中编写测试代码测试

    /**
     * 删除用户
     */
    @Test
    public void testDelete() {
        userDao.delete(52);
    }

5、模糊查询

5.1、在IUserDao中添加模糊查询方法

    /**
     * 模糊查询
     * @param username
     * @return
     */
    List<User> findByName(String username);

5.2、在IUserDao.xml中添加sql语句

    <!--根据名称查询用户-->
    <select id="findByName" parameterType="String" resultType="com.wedu.mybatis06.domain.User">
        select * from user where username like #{username}
    </select>

5.3、在UserDaoImpl实现类中实现方法

    /**
     * 根据名称查询用户
     * @param username
     * @return
     */
    @Override
    public List<User> findByName(String username) {
        SqlSession session = factory.openSession();
        List<User> users = session.selectList("com.wedu.mybatis06.dao.IUserDao.findByName", username);
        session.close();
        return users;
    }

5.4、在UserDaoTest中编写测试代码测试

    /**
     * 模糊查询
     */
    @Test
    public void testfindByName() {
        //List<User> users = userDao.findByName("王");//select * from user where username like '%王%'
        List<User> users = userDao.findByName("%王%");//select * from user where username like ?
        for (User user : users) {
            System.out.println(user);
        }
    }

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