java进阶|基于mybatis思考一些事情

        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-data-jdbc</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-jdbc</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.mybatis.spring.boot</groupId>            <artifactId>mybatis-spring-boot-starter</artifactId>            <version>2.1.2</version>        </dependency>
        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <version>5.1.46</version>        </dependency>        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>            <optional>true</optional>        </dependency>

<?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.wpw.mybatis.mapper.UserMapper">    <resultMap id="userResultMap" type="com.wpw.mybatis.entity.User">        <id property="id" column="id"/>        <result property="userName" column="user_name"/>        <result property="userAge" column="user_age"/>        <result property="userAddress" column="user_address"/>    </resultMap>    <select id="selectUserById" parameterType="int" resultMap="userResultMap">        select *        from user        where id = #{id}    </select>
    <select id="selectUser" parameterType="string" resultMap="userResultMap">        select *        from user        where user_name = #{userName}    </select>    <select id="selectUserByName" parameterType="string"  resultMap="userResultMap">        select *        from user        where user_name = #{userName}    </select>    <!--执行insert方法,useGeneratedKeys设置为"true"表明要mybatis获取由数据库自动生成的主键;    keyProperty="id" 指定把获取到的主键值注入到User的id属性-->    <insert id="insert" parameterType="User" useGeneratedKeys="true" keyProperty="id">        insert into user(user_name, user_age, user_address)        values (#{userName}, #{userAge}, #{userAddress});    </insert>
    <update id="update" parameterType="User" useGeneratedKeys="true" keyProperty="id">        update user        set user_name=#{userName},            user_age=#{userAge},            user_address=#{userAddress}        where id = #{id}    </update>    <delete id="delete" parameterType="int" >        delete        from user        where id = #{id}    </delete></mapper>

package com.wpw.mybatis.mapper;
import com.wpw.mybatis.entity.User;
import java.util.List;
/** * @author wpw */public interface UserMapper {    /**     * 根据用户id查找用户信息     *     * @param id 用户id     * @return user     */    User selectUserById(Integer id);
    /**     * 根据用户名称查询用户列表信息     *     * @param userName 用户名称     * @return userList列表     */    List<User> selectUserByName(String userName);
    /**     * 保存用户信息     *     * @param user 用户信息     * @return 自增主键     */    int insert(User user);
    /**     * 更新用户信息     *     * @param user 用户信息     * @return 主键     */    int update(User user);
    /**     * 删除用户信息     *     * @param id 用户id     */    void delete(Integer id);}

package com.wpw.mybatis.entity;
import lombok.AllArgsConstructor;import lombok.Builder;import lombok.Data;import lombok.NoArgsConstructor;import lombok.experimental.Accessors;
import java.io.Serializable;
/** * 用户类 * * @author wpw */@AllArgsConstructor@NoArgsConstructor@Data@Builder@Accessors(chain = true)public class User implements Serializable {    private Integer id;    private String userName;    private Integer userAge;    private String userAddress;}

<?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>    <!-- mybatis别名定义 -->    <typeAliases>        <typeAlias alias="User" type="com.wpw.mybatis.entity.User"/>    </typeAliases>
    <environments default="development">        <environment id="development">            <transactionManager type="JDBC"/>            <dataSource type="POOLED">                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>                <property name="url" value="jdbc:mysql://127.0.0.1:3306/springboot?serverTimezone=UTC"/>                <property name="username" value="root"/>                <property name="password" value="root"/>            </dataSource>        </environment>    </environments>
    <!-- mybatis的mapper文件，每个xml配置文件对应一个接口 -->    <mappers>        <mapper resource="com/wpw/mybatis/mapper/UserMapper.xml"/>    </mappers></configuration>

package com.wpw.mybatis;
import com.wpw.mybatis.entity.User;import com.wpw.mybatis.mapper.UserMapper;import jdk.nashorn.internal.ir.annotations.Ignore;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.jupiter.api.Test;import org.springframework.boot.test.context.SpringBootTest;
import java.io.IOException;import java.io.InputStream;import java.util.List;import java.util.Objects;import java.util.Optional;
@SpringBootTestclass MybatisApplicationTests {    private static SqlSessionFactory sqlSessionFactory;    private static InputStream inputStream;
    static {        try {            inputStream = Resources.getResourceAsStream("Configuration.xml");            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);        } catch (IOException e) {            e.printStackTrace();        }    }
    public static SqlSessionFactory getSqlSessionFactory() {        return sqlSessionFactory;    }
    @Test    @Ignore    public void testSearchUserById() {        SqlSession sqlSession = sqlSessionFactory.openSession();        try {            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);            User user = userMapper.selectUserById(1);            System.out.println("user = " + user);        } finally {            sqlSession.close();        }    }
    @Test    @Ignore    public void testSearchUserListByUserName() {        SqlSession sqlSession = sqlSessionFactory.openSession();        try {            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);            List<User> userList = userMapper.selectUserByName("test1");            userList.stream().filter(Objects::nonNull).forEach(x -> {                System.out.println("x = " + x);            });        } finally {            sqlSession.close();        }    }
    @Test    @Ignore    public void update() {        SqlSession sqlSession = sqlSessionFactory.openSession();        try {            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);            int update = userMapper.update(User.builder().build().setId(1).setUserName("ceShi").setUserAge(10).setUserAddress("hangzhou"));            System.out.println("update = " + update);            //默认不提交事务，需手动提交事务            sqlSession.commit();        } finally {            sqlSession.close();        }
    }
    @Test    @Ignore    public void insert() {        SqlSession sqlSession = sqlSessionFactory.openSession();        try {            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);            int insert = userMapper.insert(User.builder().build().setUserName("zhangSan").setUserAge(10).setUserAddress("hangzhou"));            System.out.println("insert = " + insert);            //默认不提交事务，需要手动提交            sqlSession.commit();        } finally {            sqlSession.close();        }
    }
    @Test    public void delete() {        SqlSession sqlSession = sqlSessionFactory.openSession();        try {            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);            userMapper.delete(7);            //默认不自动提交事务，需要手动提交            sqlSession.commit();        } finally {            sqlSession.close();        }    }
    @Test    void contextLoads() {    }
}