Spring Boot JPA无法获取Repository Bean：No qualifying Bean available问题

我有一个仅包含主类、Repository和实体类的简单Spring Boot JPA项目，此前启动报错已解决，但现在在主类中无法获取Repository Bean，抛出错误：
No qualifying bean of type 'com.d043114.minimalJPA.CityRepository' available

相关代码如下：

Repository代码 #

package com.d043114.minimalJPA;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface CityRepository extends CrudRepository<City, Long> {

}

实体类代码 #

package com.d043114.minimalJPA;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "cities")
public class City {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO )
    private long ID;
    
    public long getID() {
        return ID;
    }

    public void setID(long iD) {
        ID = iD;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    private String name;

}

主类代码 #

package com.d043114.minimalJPA;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

import com.d043114.minimalJPA.CityRepository;

@EnableJpaRepositories("com.d043114.minimalJPA.*")
@ComponentScan(basePackages = "com.d043114.minimalJPA.*")
@SpringBootApplication
@EntityScan("com.d043114.minimlaJPA")
public class MinimalJpaApplication {

    public static void main(String[] args) {
        ConfigurableApplicationContext appcontext = SpringApplication.run(MinimalJpaApplication.class, args);
        
        CityRepository cityRepository = appcontext.getBean(CityRepository.class );

    }

}

问题原因与解决方案 #

1. 包名拼写错误

主类中@EntityScan注解的包名写错了：com.d043114.minimlaJPA应该是com.d043114.minimalJPA（少了一个字母n），这会导致Spring无法扫描到实体类，进而影响Repository Bean的创建。

2. 多余注解导致的扫描异常

@SpringBootApplication注解本身已经包含了@ComponentScan、@EnableAutoConfiguration，并且默认会扫描主类所在包及其子包下的所有组件、Repository和实体类，所以额外添加的@EnableJpaRepositories、@ComponentScan完全是多余的，甚至可能因为通配符写法（com.d043114.minimalJPA.*）导致扫描范围出错。

修正后的主类代码 #

package com.d043114.minimalJPA;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

import com.d043114.minimalJPA.CityRepository;

@SpringBootApplication
public class MinimalJpaApplication {

    public static void main(String[] args) {
        ConfigurableApplicationContext appcontext = SpringApplication.run(MinimalJpaApplication.class, args);
        
        CityRepository cityRepository = appcontext.getBean(CityRepository.class );

    }

}

修正后，Spring会自动扫描到com.d043114.minimalJPA包下的Repository和实体类，成功创建对应的Bean，就能正常获取CityRepository实例了。

内容的提问来源于stack exchange，提问作者Habi