Mybatis-Flex 第一个版本发布，一个优雅的 Mybatis 增强框架
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
