Mybatis-Flex 第一个版本发布，一个优雅的 Mybatis 增强框架。
特征
- 1、很轻量，整个框架只依赖 Mybatis 再无其他第三方依赖
- 2、Entity 类的基本增删改查、以及分页查询
- 3、Row 通用映射支持，可以无需实体类对数据库进行增删改查
- 4、支持多种数据库类型，自由通过方言持续扩展
- 5、支持联合主键，以及不同的主键内容生成策略
- 6、极其友好的 SQL 联动查询，IDE 自动提示不再担心出错
- 7、更多小惊喜
hello world
第一步：编写 Entity 实体类
@Table("tb_account")
public class Account {
@Id()
private Long id;
private String userName;
private Date birthday;
private int sex;
//getter setter
}
第二步，编写 Mapper 类，并继承 BaseMapper
public interface AccountMapper extends BaseMapper<Account> {
//只需定义 Mapper 接口即可，可以无任何内容。
}
第三步：开始查询数据
示例 1：查询 1 条数据
class HelloWorld {
public static void main(String... args) {
HikariDataSource dataSource = new HikariDataSource();
dataSource.setJdbcUrl("jdbc:mysql://127.0.0.1:3306/mybatis-flex");
dataSource.setUsername("username");
dataSource.setPassword("password");
MybatisFlexBootstrap.getInstance()
.setDatasource(dataSource)
.addMapper(AccountMapper.class)
.start();
//示例1：查询 id=100 条数据
Account account = MybatisFlexBootstrap.getInstance()
.execute(AccountMapper.class, mapper ->
mapper.selectOneById(100)
);
}
}
示例2：查询列表
class HelloWorld {
public static void main(String... args) {
HikariDataSource dataSource = new HikariDataSource();
dataSource.setJdbcUrl("jdbc:mysql://127.0.0.1:3306/mybatis-flex");
dataSource.setUsername("username");
dataSource.setPassword("password");
MybatisFlexBootstrap.getInstance()
.setDatasource(dataSource)
.addMapper(AccountMapper.class)
.start();
//示例2：通过 QueryWrapper 构建条件查询数据列表
QueryWrapper query = QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(ACCOUNT.USER_NAME.like("张").or(ACCOUNT.USER_NAME.like("李")));
// 执行 SQL：
// ELECT * FROM `tb_account`
// WHERE `tb_account`.`id` >= 100
// AND (`tb_account`.`user_name` LIKE '%张%' OR `tb_account`.`user_name` LIKE '%李%' )
List<Account> accounts = MybatisFlexBootstrap.getInstance()
.execute(AccountMapper.class, mapper ->
mapper.selectListByQuery(query)
);
}
}
示例3：分页查询
class HelloWorld {
public static void main(String... args) {
HikariDataSource dataSource = new HikariDataSource();
dataSource.setJdbcUrl("jdbc:mysql://127.0.0.1:3306/mybatis-flex");
dataSource.setUsername("username");
dataSource.setPassword("password");
MybatisFlexBootstrap.getInstance()
.setDatasource(dataSource)
.addMapper(AccountMapper.class)
.start();
// 示例3：分页查询
// 查询第 5 页，每页 10 条数据，通过 QueryWrapper 构建条件查询
QueryWrapper query = QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(ACCOUNT.USER_NAME.like("张").or(ACCOUNT.USER_NAME.like("李")))
.orderBy(ACCOUNT.ID.desc());
// 执行 SQL：
// ELECT * FROM `tb_account`
// WHERE `tb_account`.`id` >= 100
// AND (`tb_account`.`user_name` LIKE '%张%' OR `tb_account`.`user_name` LIKE '%李%' )
// ORDER BY `tb_account`.`id` DESC
// LIMIT 40,10
Page<Account> accounts = MybatisFlexBootstrap.getInstance()
.execute(AccountMapper.class, mapper ->
mapper.paginate(5, 10, query)
);
}
}
QueryWrapper 示例
select *
QueryWrapper query=new QueryWrapper();
query.select().from(ACCOUNT)
// SQL:
// SELECT * FROM tb_account
select columns
QueryWrapper query=new QueryWrapper();
query.select(ACCOUNT.ID,ACCOUNT.USER_NAME).from(ACCOUNT)
// SQL:
// SELECT tb_account.id, tb_account.user_name
// FROM tb_account
QueryWrapper query=new QueryWrapper();
query.select(ACCOUNT.ALL_COLUMNS).from(ACCOUNT)
// SQL:
// SELECT tb_account.id, tb_account.user_name, tb_account.birthday,
// tb_account.sex, tb_account.is_normal
// FROM tb_account
select functions
QueryWrapper query=new QueryWrapper()
.select(ACCOUNT.ID
,ACCOUNT.USER_NAME
,max(ACCOUNT.BIRTHDAY)
,avg(ACCOUNT.SEX).as("sex_avg"))
.from(ACCOUNT);
// SQL:
// SELECT tb_account.id, tb_account.user_name,
// MAX(tb_account.birthday),
// AVG(tb_account.sex) AS sex_avg
// FROM tb_account
where
QueryWrapper queryWrapper=QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(ACCOUNT.USER_NAME.like("michael"));
// SQL:
// SELECT * FROM tb_account
// WHERE tb_account.id >= ?
// AND tb_account.user_name LIKE ?
exists, not exists
QueryWrapper queryWrapper=QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(
exist(
selectOne().from(ARTICLE).where(ARTICLE.ID.ge(100))
)
);
// SQL:
// SELECT * FROM tb_account
// WHERE tb_account.id >= ?
// AND EXIST (
// SELECT 1 FROM tb_article WHERE tb_article.id >= ?
// )
and (...) or (...)
QueryWrapper queryWrapper=QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(ACCOUNT.SEX.eq(1).or(ACCOUNT.SEX.eq(2)))
.or(ACCOUNT.AGE.in(18,19,20).or(ACCOUNT.USER_NAME.like("michael")));
// SQL:
// SELECT * FROM tb_account
// WHERE tb_account.id >= ?
// AND (tb_account.sex = ? OR tb_account.sex = ? )
// OR (tb_account.age IN (?,?,?) OR tb_account.user_name LIKE ? )
group by
QueryWrapper queryWrapper=QueryWrapper.create()
.select()
.from(ACCOUNT)
.groupBy(ACCOUNT.USER_NAME);
// SQL:
// SELECT * FROM tb_account
// GROUP BY tb_account.user_name
having
QueryWrapper queryWrapper=QueryWrapper.create()
.select()
.from(ACCOUNT)
.groupBy(ACCOUNT.USER_NAME)
.having(ACCOUNT.AGE.between(18,25));
// SQL:
// SELECT * FROM tb_account
// GROUP BY tb_account.user_name
// HAVING tb_account.age BETWEEN ? AND ?
jion
QueryWrapper queryWrapper = QueryWrapper.create()
.select()
.from(ACCOUNT)
.leftJoin(ARTICLE).on(ACCOUNT.ID.eq(ARTICLE.ACCOUNT_ID))
.where(ACCOUNT.AGE.ge(10));
// SQL:
// SELECT * FROM tb_account
// LEFT JOIN tb_article
// ON tb_account.id = tb_article.account_id
// WHERE tb_account.age >= ?
可能存在问题
如何通过实体类 Account.java 生成 QueryWrapper 所需要的 "ACCOUNT" 类 ?
答：通过开发工具构建项目（如下图），或者执行 maven 编译命令: mvn clean package
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更多示例
