阿里官宣：干掉Mybatis和MybatisPlus，推出新一代ORM框架FluentMybatis，太牛逼了！
阅读本文大概需要 5 分钟。
需求场景设置
create table `student_score`
(
id bigint auto_increment comment '主键ID' primary key,
student_id bigint not null comment '学号',
gender_man tinyint default 0 not null comment '性别, 0:女; 1:男',
school_term int null comment '学期',
subject varchar(30) null comment '学科',
score int null comment '成绩',
gmt_create datetime not null comment '记录创建时间',
gmt_modified datetime not null comment '记录最后修改时间',
is_deleted tinyint default 0 not null comment '逻辑删除标识'
) engine = InnoDB default charset=utf8;
复制代码
select school_term,
subject,
count(score) as count,
min(score) as min_score,
max(score) as max_score,
avg(score) as max_score
from student_score
where school_term >= 2000
and subject in ('英语', '数学', '语文')
and score >= 60
and is_deleted = 0
group by school_term, subject
having count(score) > 1
order by school_term, subject;
复制代码
三者实现对比
使用fluent mybatis 来实现上面的功能
换成mybatis原生实现效果
定义Mapper接口
public interface MyStudentScoreMapper {
List<Map<String, Object>> summaryScore(SummaryQuery paras);
}
复制代码
定义接口需要用到的参数实体 SummaryQuery
@Data
@Accessors(chain = true)
public class SummaryQuery {
private Integer schoolTerm;
private List<String> subjects;
private Integer score;
private Integer minCount;
}
复制代码
定义实现业务逻辑的mapper xml文件
<select id="summaryScore" resultType="map" parameterType="cn.org.fluent.mybatis.springboot.demo.mapper.SummaryQuery">
select school_term,
subject,
count(score) as count,
min(score) as min_score,
max(score) as max_score,
avg(score) as max_score
from student_score
where school_term >= #{schoolTerm}
and subject in
<foreach collection="subjects" item="item" open="(" close=")" separator=",">
#{item}
</foreach>
and score >= #{score}
and is_deleted = 0
group by school_term, subject
having count(score) > #{minCount}
order by school_term, subject
</select>
复制代码
实现业务接口(这里是测试类, 实际应用中应该对应Dao类)
@RunWith(SpringRunner.class)
@SpringBootTest(classes = QuickStartApplication.class)
public class MybatisDemo {
@Autowired
private MyStudentScoreMapper mapper;
@Test
public void mybatis_demo() {
// 构造查询参数
SummaryQuery paras = new SummaryQuery()
.setSchoolTerm(2000)
.setSubjects(Arrays.asList("英语", "数学", "语文"))
.setScore(60)
.setMinCount(1);
List<Map<String, Object>> summary = mapper.summaryScore(paras);
System.out.println(summary);
}
}
复制代码
换成mybatis plus实现效果
字段名称的记忆和敲码困难 Entity属性跟随数据库字段发生变更后的运行时错误
生成代码编码比较
fluent mybatis生成代码设置
public class AppEntityGenerator {
static final String url = "jdbc:mysql://localhost:3306/fluent_mybatis_demo?useSSL=false&useUnicode=true&characterEncoding=utf-8";
public static void main(String[] args) {
FileGenerator.build(Abc.class);
}
@Tables(
/** 数据库连接信息 **/
url = url, username = "root", password = "password",
/** Entity类parent package路径 **/
basePack = "cn.org.fluent.mybatis.springboot.demo",
/** Entity代码源目录 **/
srcDir = "spring-boot-demo/src/main/java",
/** Dao代码源目录 **/
daoDir = "spring-boot-demo/src/main/java",
/** 如果表定义记录创建，记录修改，逻辑删除字段 **/
gmtCreated = "gmt_create", gmtModified = "gmt_modified", logicDeleted = "is_deleted",
/** 需要生成文件的表 ( 表名称:对应的Entity名称 ) **/
tables = @Table(value = {"student_score"})
)
static class Abc {
}
}
复制代码
mybatis plus代码生成设置
public class CodeGenerator {
static String dbUrl = "jdbc:mysql://localhost:3306/fluent_mybatis_demo?useSSL=false&useUnicode=true&characterEncoding=utf-8";
@Test
public void generateCode() {
GlobalConfig config = new GlobalConfig();
DataSourceConfig dataSourceConfig = new DataSourceConfig();
dataSourceConfig.setDbType(DbType.MYSQL)
.setUrl(dbUrl)
.setUsername("root")
.setPassword("password")
.setDriverName(Driver.class.getName());
StrategyConfig strategyConfig = new StrategyConfig();
strategyConfig
.setCapitalMode(true)
.setEntityLombokModel(false)
.setNaming(NamingStrategy.underline_to_camel)
.setColumnNaming(NamingStrategy.underline_to_camel)
.setEntityTableFieldAnnotationEnable(true)
.setFieldPrefix(new String[]{"test_"})
.setInclude(new String[]{"student_score"})
.setLogicDeleteFieldName("is_deleted")
.setTableFillList(Arrays.asList(
new TableFill("gmt_create", FieldFill.INSERT),
new TableFill("gmt_modified", FieldFill.INSERT_UPDATE)));
config
.setActiveRecord(false)
.setIdType(IdType.AUTO)
.setOutputDir(System.getProperty("user.dir") + "/src/main/java/")
.setFileOverride(true);
new AutoGenerator().setGlobalConfig(config)
.setDataSource(dataSourceConfig)
.setStrategy(strategyConfig)
.setPackageInfo(
new PackageConfig()
.setParent("com.mp.demo")
.setController("controller")
.setEntity("entity")
).execute();
}
}
复制代码
FluentMybatis特性一览
三者对比总结
| - | Mybatis Plus | Fluent Mybatis |
|---|---|---|
| 代码生成 | 生成 Entity | 生成Entity, 再通过编译生成 Mapper, Query, Update 和 SqlProvider |
| Generator易用性 | 低 | 高 |
| 和Mybatis的共生关系 | 需替换原有的SqlSessionFactoryBean | 对Mybatis没有任何修改,原来怎么用还是怎么用 |
| 动态SQL构造方式 | 应用启动时, 根据Entity注解信息构造动态xml片段，注入到Mybatis解析器 | 应用编译时，根据Entity注解，编译生成对应方法的SqlProvider，利用mybatis的Mapper上@InsertProvider @SelectProvider @UpdateProvider注解关联 |
| 动态SQL结果是否容易DEBUG跟踪 | 不容易debug | 容易，直接定位到SQLProvider方法上，设置断点即可 |
| 动态SQL构造 | 通过硬编码字段名称, 或者利用Entity的get方法的lambda表达式 | 通过编译手段生成对应的方法名，直接调用方法即可 |
| 字段变更后的错误发现 | 通过get方法的lambda表达的可以编译发现，通过字段编码的无法编译发现 | 编译时便可发现 |
| 不同字段动态SQL构造方法 | 通过接口参数方式 | 通过接口名称方式, FluentAPI的编码效率更高 |
| 语法渲染特点 | 无 | 通过关键变量select, update, set, and, or可以利用IDE语法渲染, 可读性更高 |