Spring Boot中Unsatisfied Dependency依赖注入错误求助

问题现象 #

启动Spring Boot项目时出现依赖注入失败，具体报错：

• 创建employeeController Bean失败，字段employeeRepository存在未满足的依赖
• 根源是创建employeeRepository Bean失败，提示Not a managed type: class in.test.model.Employee
• 已尝试添加@EntityScan("base package")注解，但问题未解决

项目代码 #

pom.xml #

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.0.2</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>in.test</groupId>
    <artifactId>test-site</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>test-site</name>
    <description>test site</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>javax.persistence</groupId>
            <artifactId>javax.persistence-api</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

主应用类 #

@SpringBootApplication
@ComponentScan({ "in.test" })
public class TestApplication {

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

}

Controller类 #

@CrossOrigin(origins = "http://localhost:4200")
@RestController
@RequestMapping("/api/v1/")
public class TestController {

    @Autowired
    private EmployeeRepository employeeRepository;
    
    // get all employees
    @GetMapping("/employees")
    public List<Employee> getAllEmployees(){
        return employeeRepository.findAll();
    }       
    
    // create employee rest api
    @PostMapping("/employees")
    public Employee createEmployee(@RequestBody Employee employee) {
        return employeeRepository.save(employee);
    }
    
    // get employee by id rest api
    @GetMapping("/employees/{id}")
    public ResponseEntity<Employee> getEmployeeById(@PathVariable Long id) {
        Employee employee = employeeRepository.findById(id)
                .orElseThrow(() -> new ResourceNotFoundException("Employee not exist with id :" + id));
        return ResponseEntity.ok(employee);
    }
    
    // update employee rest api
    
    @PutMapping("/employees/{id}")
    public ResponseEntity<Employee> updateEmployee(@PathVariable Long id, @RequestBody Employee employeeDetails){
        Employee employee = employeeRepository.findById(id)
                .orElseThrow(() -> new ResourceNotFoundException("Employee not exist with id :" + id));
        
        employee.setFirstName(employeeDetails.getFirstName());
        employee.setLastName(employeeDetails.getLastName());
        employee.setEmailId(employeeDetails.getEmailId());
        
        Employee updatedEmployee = employeeRepository.save(employee);
        return ResponseEntity.ok(updatedEmployee);
    }
    
    // delete employee rest api
    @DeleteMapping("/employees/{id}")
    public ResponseEntity<Map<String, Boolean>> deleteEmployee(@PathVariable Long id){
        Employee employee = employeeRepository.findById(id)
                .orElseThrow(() -> new ResourceNotFoundException("Employee not exist with id :" + id));
        
        employeeRepository.delete(employee);
        Map<String, Boolean> response = new HashMap<>();
        response.put("deleted", Boolean.TRUE);
        return ResponseEntity.ok(response);
    }
}

Entity类 #

@Entity
@Table(name = "employees")
public class Employee {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;
    
    @Column(name = "first_name")
    private String firstName;

    @Column(name = "last_name")
    private String lastName;
    
    @Column(name = "email_id")
    private String emailId;
    
    public Employee() {
        
    }
    
    public Employee(String firstName, String lastName, String emailId) {
        super();
        this.firstName = firstName;
        this.lastName = lastName;
        this.emailId = emailId;
    }
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getEmailId() {
        return emailId;
    }
    public void setEmailId(String emailId) {
        this.emailId = emailId;
    }
}

错误日志 #

java.lang.IllegalStateException: Failed to load ApplicationContext for [WebMergedContextConfiguration@2a075e70 testClass = in.test.site.MentorsSiteApplicationTests, locations = [], classes = [in.test.site.SiteApplication], contextInitializerClasses = [], activeProfiles = [], propertySourceLocations = [], propertySourceProperties = ["org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true"], contextCustomizers = [org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizer@9573584, org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory$DuplicateJsonObjectContextCustomizer@6853425f, org.springframework.boot.test.mock.mockito.MockitoContextCustomizer@0, org.springframework.boot.test.web.client.TestRestTemplateContextCustomizer@41294f8, org.springframework.boot.test.autoconfigure.actuate.observability.ObservabilityContextCustomizerFactory$DisableObservabilityContextCustomizer@9da1, org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCustomizer@0, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverContextCustomizerFactory$Customizer@3af0a9da, org.springframework.boot.test.context.SpringBootTestAnnotation@c4346d6c], resourceBasePath = "src/main/webapp", contextLoader = org.springframework.boot.test.context.SpringBootContextLoader, parent = null]
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:142) ~[spring-test-6.0.4.jar:6.0.4]
    at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:127) ~[spring-test-6.0.4.jar:6.0.4]
    at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:191) ~[spring-test-6.0.4.jar:6.0.4]

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'employeeController': Unsatisfied dependency expressed through field 'employeeRepository': Error creating bean with name 'employeeRepository' defined in in.test.repository.EmployeeRepository defined in @EnableJpaRepositories declared on JpaRepositoriesRegistrar.EnableJpaRepositoriesConfiguration: Not a managed type: class in.test.model.Employee
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:712) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:692) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:133) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:481) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1397) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:598) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:521) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:326) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:324) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:961) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:915) 
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeRepository' defined in in.test.repository.EmployeeRepository defined in @EnableJpaRepositories declared on JpaRepositoriesRegistrar.EnableJpaRepositoriesConfiguration: Not a managed type: class in.test.model.Employee
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1751) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:599) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:521) 
Caused by: java.lang.IllegalArgumentException: Not a managed type: class in.test.model.Employee
    at org.hibernate.metamodel.model.domain.internal.JpaMetamodelImpl.managedType(JpaMetamodelImpl.java:181) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.metamodel.model.domain.internal.MappingMetamodelImpl.managedType(MappingMetamodelImpl.java:496) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.metamodel.model.domain.internal.MappingMetamodelImpl.managedType(MappingMetamodelImpl.java:99) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.<init>(JpaMetamodelEntityInformation.java:77) ~[spring-data-jpa-3.0.1.jar:3.0.1]
    at org.springframework.data.jpa.repository.support.JpaEntityInformationSupport.getEntityInformation(JpaEntityInformationSupport.java:69) 

解决方案 #

1. 移除冲突的JPA依赖 #

Spring Boot 3.x基于Jakarta EE 9+，使用jakarta.persistence包下的注解，你添加的javax.persistence-api依赖会和Spring Boot自带的Jakarta JPA冲突。直接删除pom.xml中的以下依赖：

<dependency>
    <groupId>javax.persistence</groupId>
    <artifactId>javax.persistence-api</artifactId>
    <version>2.2</version>
</dependency>

2. 修正Entity类的注解导入 #

确保Employee类中的@Entity、@Table、@Id等注解来自jakarta.persistence包，替换原有导入：

import jakarta.persistence.Entity;
import jakarta.persistence.Table;
import jakarta.persistence.Id;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Column;

3. 明确指定扫描范围（可选但推荐） #

在主应用类上添加@EntityScan和@EnableJpaRepositories注解，明确指定实体类和Repository类的包路径，避免扫描范围遗漏：

@SpringBootApplication
@ComponentScan("in.test")
@EntityScan("in.test.model")
@EnableJpaRepositories("in.test.repository")
public class TestApplication {

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

}

4. 清理并重新构建项目 #

执行Maven命令清理缓存并重新构建：

mvn clean install

完成以上步骤后，重新启动项目即可解决依赖注入和实体类未被管理的问题。

内容的提问来源于stack exchange，提问作者SOP