Mybatis 笔记 022（动态SQL环境搭建）

内容来自B站【狂神说Java】Mybatis最新完整教程IDEA版通俗易懂

搭建环境

1. sql

CREATE TABLE `blog` (
	`id` VARCHAR(50) NOT NULL COMMENT '博客id',
	`title` VARCHAR(100) NOT NULL COMMENT '博客标题',
	`author` VARCHAR(30) NOT NULL COMMENT '博客作者',
	`create_time` DATETIME NOT NULL COMMENT '创建时间',
	`views` INT(30) NOT NULL COMMENT '浏览量'
) ENGINE=INNODB DEFAULT CHARSET=UTF8;

2. 配置文件

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/study_mybatis?useSSL=true&useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8
username=root
password=root

<?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 核心配置文件-->
<configuration>

    <!-- 引入外部配置文件 -->
    <properties resource="db.properties"/>

    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>

    <!-- 可以给实体类起别名 -->
    <typeAliases>
        <package name="org.example.mybatis08.pojo"/>
    </typeAliases>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>

    <!-- 绑定接口-->
    <mappers>
        <package name="org.example.mybatis08.mapper"/>
    </mappers>

</configuration>

3. 工具类

package org.example.mybatis08.utils;

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

public class MybatisUtils {

    private static SqlSessionFactory sqlSessionFactory;

    static {
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static SqlSession getSqlSession() {
        return sqlSessionFactory.openSession();
    }

    public static SqlSession getSqlSession(boolean autoCommit) {
        return sqlSessionFactory.openSession(true);
    }

}

package org.example.mybatis08.utils;

import java.util.UUID;

public class IDUtils {

    public static String getId() {
        return UUID.randomUUID().toString().replaceAll("-", "");
    }

}

4. 实体类

package org.example.mybatis08.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.Date;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Blog {

    private String id;
    private String title;
    private String author;
    private Date createTime;
    private Integer views;

}

5. mapper

package org.example.mybatis08.mapper;

import org.example.mybatis08.pojo.Blog;

public interface BlogMapper {

    int addBlog(Blog blog);

}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.example.mybatis08.mapper.BlogMapper">

    <insert id="addBlog" parameterType="blog">
        insert into `blog` (`id`, `title`, `author`, `create_time`, `views`)
        values (#{id}, #{title}, #{author}, #{createTime}, #{views})
    </insert>

</mapper>

6. 测试类

package org.example.mybatis08.utils;

import org.junit.Test;

public class IDUtilsTest {

    @Test
    public void testGetId() {
        System.out.println(IDUtils.getId());
    }

}

package org.example.mybatis08.mapper;

import org.apache.ibatis.session.SqlSession;
import org.example.mybatis08.pojo.Blog;
import org.example.mybatis08.utils.IDUtils;
import org.example.mybatis08.utils.MybatisUtils;
import org.junit.Test;

import java.util.Date;

public class BlogMapperTest {

    @Test
    public void testAddBlog() {
        try (SqlSession sqlSession = MybatisUtils.getSqlSession(true)) {
            BlogMapper mapper = sqlSession.getMapper(BlogMapper.class);
            mapper.addBlog(new Blog(IDUtils.getId(), "Mybatis如此简单", "墨倾池", new Date(), 9999));
            mapper.addBlog(new Blog(IDUtils.getId(), "Java如此简单", "砚寒清", new Date(), 8888));
            mapper.addBlog(new Blog(IDUtils.getId(), "Spring如此简单", "欲星移", new Date(), 7777));
            mapper.addBlog(new Blog(IDUtils.getId(), "微服务如此简单", "雁王", new Date(), 6666));
        }
    }

}