Spring Data 2027 @Query 注解：灵活构建自定义查询-开发者社区

Spring Data 2027 @Query 注解：灵活构建自定义查询

核心概念

Spring Data 2027 的 @Query 注解允许开发者使用 JPQL（Java Persistence Query Language）或原生 SQL 编写自定义查询，提供了比方法名查询更灵活的查询方式。@Query 注解可以用于方法上，指定查询语句，支持参数绑定、结果映射等功能。

工作原理

@Query 注解的工作原理如下：

查询定义：在方法上使用 @Query 注解，指定 JPQL 或原生 SQL 查询语句
参数绑定：使用命名参数或位置参数绑定方法参数
结果映射：将查询结果映射到实体类或DTO
查询执行：Spring Data 执行查询并返回结果

代码示例

1. 基本用法

// 基本 JPQL 查询 public interface UserRepository extends JpaRepository<User, Long> { @Query("SELECT u FROM User u WHERE u.name = :name") User findByName(@Param("name") String name); @Query("SELECT u FROM User u WHERE u.age > :age") List<User> findByAgeGreaterThan(@Param("age") int age); @Query("SELECT u FROM User u WHERE u.name LIKE %:name%") List<User> findByNameLike(@Param("name") String name); } // 原生 SQL 查询 public interface UserRepository extends JpaRepository<User, Long> { @Query(value = "SELECT * FROM users WHERE name = :name", nativeQuery = true) User findByNameNative(@Param("name") String name); @Query(value = "SELECT * FROM users WHERE age > :age", nativeQuery = true) List<User> findByAgeGreaterThanNative(@Param("age") int age); }

2. 复杂查询

// 复杂 JPQL 查询 public interface UserRepository extends JpaRepository<User, Long> { @Query("SELECT u FROM User u WHERE u.age BETWEEN :minAge AND :maxAge") List<User> findByAgeBetween(@Param("minAge") int minAge, @Param("maxAge") int maxAge); @Query("SELECT u FROM User u WHERE u.name LIKE %:name% AND u.age > :age") List<User> findByNameLikeAndAgeGreaterThan(@Param("name") String name, @Param("age") int age); @Query("SELECT u FROM User u JOIN u.roles r WHERE r.name = :roleName") List<User> findByRoleName(@Param("roleName") String roleName); } // 复杂原生 SQL 查询 public interface UserRepository extends JpaRepository<User, Long> { @Query(value = "SELECT u.* FROM users u JOIN user_roles ur ON u.id = ur.user_id JOIN roles r ON ur.role_id = r.id WHERE r.name = :roleName", nativeQuery = true) List<User> findByRoleNameNative(@Param("roleName") String roleName); @Query(value = "SELECT u.* FROM users u WHERE u.created_at BETWEEN :startDate AND :endDate", nativeQuery = true) List<User> findByCreatedAtBetweenNative(@Param("startDate") LocalDateTime startDate, @Param("endDate") LocalDateTime endDate); }

3. 更新和删除操作

// 更新操作 public interface UserRepository extends JpaRepository<User, Long> { @Modifying @Query("UPDATE User u SET u.name = :name WHERE u.id = :id") int updateUserName(@Param("id") Long id, @Param("name") String name); @Modifying @Query("UPDATE User u SET u.age = :age WHERE u.id = :id") int updateUserAge(@Param("id") Long id, @Param("age") int age); } // 删除操作 public interface UserRepository extends JpaRepository<User, Long> { @Modifying @Query("DELETE FROM User u WHERE u.id = :id") int deleteUserById(@Param("id") Long id); @Modifying @Query("DELETE FROM User u WHERE u.age < :age") int deleteUsersByAgeLessThan(@Param("age") int age); }

4. 结果映射

// 映射到实体类 public interface UserRepository extends JpaRepository<User, Long> { @Query("SELECT u FROM User u WHERE u.id = :id") User findUserById(@Param("id") Long id); } // 映射到DTO public interface UserRepository extends JpaRepository<User, Long> { @Query("SELECT new com.example.dto.UserDTO(u.id, u.name, u.email) FROM User u WHERE u.age > :age") List<UserDTO> findUserDTOsByAgeGreaterThan(@Param("age") int age); } // 映射到投影 public interface UserProjection { Long getId(); String getName(); String getEmail(); } public interface UserRepository extends JpaRepository<User, Long> { @Query("SELECT u.id as id, u.name as name, u.email as email FROM User u WHERE u.age > :age") List<UserProjection> findUserProjectionsByAgeGreaterThan(@Param("age") int age); }