Spring Boot多模块下@Entity非托管类型问题求助

我一整天都在排查问题，查了大量资料，改了很多地方，但完全没进展。我有个数据库模块，里面有标注@Entity的Company类，还有对应的Repository和服务类。一开始这些类在子包里，我试过把它们移到同一个包，甚至把所有代码从模块移到主应用里，问题还是没解决。逐字检查过代码，没发现拼写或大小写错误。附上相关代码，日志太长超过字符限制，求帮忙排查原因。

实体类代码 #

@NoArgsConstructor
@AllArgsConstructor
@Getter
@ToString
@Entity
@Table(name = "company")
public class Company {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "company_id", nullable = false)
    private long id;

    @Column(name = "company_name", nullable = false)
    private String name;

    @Column(name = "addr1")
    private String adress1;

    @Column(name = "addr2")
    private String adress2;

    @Column(name = "addr3")
    private String adress3;

    @Column(name = "addr4")
    private String adress4;

    @Column(name = "postcode")
    private String postcode;
}

Repository代码 #

@Repository
public interface CompanyRepository extends JpaRepository<Company, Long> {
    List<Company> findByName(String companyName);

    @Query("SELECT c FROM Company c WHERE LOWER(c.name) LIKE LOWER(concat('%', :name,'%'))")
    List<Company> findByNameLike(@Param("name") String name);
}

服务类代码 #

@Service
public class DatabaseService {
    private final CompanyRepository companyRepository;

    @Autowired
    public DatabaseService(CompanyRepository companyRepository) {
        this.companyRepository = companyRepository;
    }

    public List<Company> findByName(String companyName) {
        return companyRepository.findByName(companyName);
    }

    public List<Company> findByNameLike(String companyName) {
        return companyRepository.findByNameLike(companyName);
    }
}

数据库模块Gradle配置 #

plugins {
    java
    idea
    id("org.springframework.boot") version "3.2.4"
    id("io.spring.dependency-management") version "1.1.4"
}

group = "co.uk.myapp"
version = "0.0.1-SNAPSHOT"

val lombokVersion = "1.18.30"

repositories {
    mavenCentral()
}

dependencies {
    compileOnly("org.projectlombok:lombok:$lombokVersion")
    annotationProcessor("org.projectlombok:lombok:$lombokVersion")

    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
    implementation( "org.postgresql:postgresql:42.7.2")
    implementation( "com.zaxxer:HikariCP:5.1.0")

    testImplementation(platform("org.junit:junit-bom:5.10.0"))
    testImplementation("org.junit.jupiter:junit-jupiter")
}

tasks.test {
    useJUnitPlatform()
}

主项目Gradle配置 #

dependencies {
    implementation(project(":database"))

    compileOnly("org.projectlombok:lombok:$lombokVersion")
    annotationProcessor("org.projectlombok:lombok:$lombokVersion")

    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
    implementation("org.springframework.boot:spring-boot-starter-data-rest")
    implementation("org.springframework.boot:spring-boot-starter-web")
    implementation("org.springframework.boot:spring-boot-starter-webflux")
    implementation("org.springframework.boot:spring-boot-starter-actuator")
    implementation("org.springframework.boot:spring-boot-starter-thymeleaf")
    implementation("org.springframework.session:spring-session-core")

    developmentOnly("org.springframework.boot:spring-boot-devtools")

    testImplementation("org.springframework.boot:spring-boot-starter-test")
    testImplementation("io.projectreactor:reactor-test")
}

application.yml配置 #

spring:
  application:
    name: "Management App"
  main:
    allow-bean-definition-overriding: true
  thymeleaf:
  cache: false
  datasource:
  driver-class-name: org.postgresql.Driver
  url: jdbc:postgresql://localhost:5000/management
  username: user_man
  password:
  statement-cache-size: 250
  statement-cache-sql-limit: 2048
  hikari:
    pool-name: MyHikariPool
    connection-timeout: 30000
    maximum-pool-size: 10
    minimum-idle: 5
    idle-timeout: 600000
    max-lifetime: 1800000   

主类代码 #

@SpringBootApplication(scanBasePackages = {"co.uk.training", "co.uk.training.management" })
@EnableJpaRepositories(basePackageClasses = {CompanyRepository.class})
@EntityScan(basePackages = {"co.uk.training.database.entity"})
public class TrainingApplication {

    public static void main(String[] args) {
        SpringApplication.run(TrainingApplication.class, args);
    }
}

排查要点及解决方案 #

1. 包路径不匹配 #

• 检查@EntityScan指定的co.uk.training.database.entity是否与Company类的实际包完全一致。从数据库模块的group是co.uk.myapp来看，Company类的包大概率是co.uk.myapp.database.entity，而非co.uk.training.database.entity，这会导致实体类无法被扫描到。
• 建议改用@EntityScan(basePackageClasses = {Company.class})，直接指定实体类字节码，避免字符串路径拼写错误。

2. Lombok构造方法访问权限问题 #

• JPA要求实体类必须有公开的无参构造方法，当前@NoArgsConstructor默认生成private的无参构造，部分JPA实现无法识别。修改为：

  @NoArgsConstructor(access = AccessLevel.PUBLIC)
  

• 可以通过查看编译后的class文件确认构造方法是否正确生成，或者临时去掉Lombok，手动编写无参构造测试。

3. 多模块JPA依赖重复 #

• 主项目和数据库模块都引入了spring-boot-starter-data-jpa，可能导致依赖冲突或重复初始化。建议只在数据库模块保留该依赖，主项目依赖数据库模块即可，删除主项目Gradle中的implementation("org.springframework.boot:spring-boot-starter-data-jpa")。

4. YAML配置缩进错误 #

• 当前application.yml中thymeleaf和datasource的配置存在缩进错误，导致数据源配置不生效，JPA无法初始化实体。修正后的正确格式：

  spring:
    application:
      name: "Management App"
    main:
      allow-bean-definition-overriding: true
    thymeleaf:
      cache: false
    datasource:
      driver-class-name: org.postgresql.Driver
      url: jdbc:postgresql://localhost:5000/management
      username: user_man
      password:
      statement-cache-size: 250
      statement-cache-sql-limit: 2048
      hikari:
        pool-name: MyHikariPool
        connection-timeout: 30000
        maximum-pool-size: 10
        minimum-idle: 5
        idle-timeout: 600000
        max-lifetime: 1800000
  

5. 实体ID类型不匹配 #

• Company类的id是基本类型long，而Repository泛型是包装类型Long，虽然多数情况能兼容，但部分场景下可能导致类型识别异常。将id改为包装类型：

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  @Column(name = "company_id", nullable = false)
  private Long id;
  

6. 数据库模块Spring Boot插件配置问题 #

• 数据库模块作为子模块，不需要使用org.springframework.boot插件（该插件会将子模块打包为独立Spring Boot应用），去掉数据库模块Gradle中的id("org.springframework.boot") version "3.2.4"，仅保留io.spring.dependency-management插件管理依赖即可。

内容的提问来源于stack exchange，提问作者Ian