org.springframework.beans.factory.NoSuchBeanDefinitionException：@Autowired在Spring Boot中不起作用

Question

我目前正在使用Spring Boot應用程序，而@Autowired不適用於我的主類，僅適用於測試類。 我已經嘗試過其他解決方案，但到目前為止，對我來說沒有任何幫助。

我得到的錯誤是

org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.johndoe.handler.MyHandler' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

和

org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.johndoe.repos.MyDataRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)} org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.johndoe.repos.MyDataRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)} 。

我當前的項目結構可以抽象為：

MyProject
|- Some other folders and files
|- MyApplicationFolder
   |- build.gradle
   |- bin
   |- build
   |- src
      |- main
         |- java
            |- com
               |- johndoe
                  |- repos
                     |- MyDataRepository.java
                  |- data
                     |- MyData.java
                  |- myapp
                     |- MyApplication.java
                  |- handler
                     |- MyHandler.java
                  |- request
                     |- MyRequest.java
         |- resources
      |- test

在MyApplication.java中：

package com.johndoe.myapp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication(scanBasePackages = {"com.johndoe", "com.johndoe.repos", "com.johndoe.data", "com.johndoe.myapp", "com.johndoe.handler", "com.johndoe.request"})
@EnableJpaRepositories("com.johndoe.repos")
public class MyApplication {
    public static void main(String[] args) {        
        SpringApplication.run(MyApplication.class, args);
    }
}

在MyData.java中：

package com.johndoe.data;

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

@Data
@Entity
@Table(name = "my_table")
public class MyData {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private String id;

    // More data members
}

在MyDataRepository.java中：

package com.johndoe.repos;

import com.johndoe.data.MyData;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
import java.util.*;

@Repository
public interface MyDataRepository extends CrudRepository<Tour, Long> {
    List<MyData> findAll();

    // More functions
}

在MyRequest.java中：

package com.johndoe.request;

import org.springframework.stereotype.Component;

@Component
public class MyRequest {
    // More code
}

在MyHandler.java中：

package com.johndoe.handler;

import com.johndoe.request.MyRequest;
import com.johndoe.data.MyData;
import com.johndoe.repos.MyDataRepository;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class MyHandler {
    @Autowired
    private MyDataRepository repo;
    @Autowired
    private MyRequest req;

    // More code
}

在build.gradle中：

apply plugin: 'org.springframework.boot'

dependencies {
    compile project(':<other folder in MyProject>')
    compile("org.springframework.boot:spring-boot-starter-data-jpa:1.5.6.RELEASE")
    compile("org.springframework.boot:spring-boot-starter-test") 
    compile("org.hsqldb:hsqldb:2.3.0")
    compile("org.springframework.boot:spring-boot-starter-web") {
        exclude module: "spring-boot-starter-tomcat"
    }
    compile("org.springframework.boot:spring-boot-autoconfigure")
}

構建此文件將導致上述錯誤，但我不確定為什么。 我不確定我在做什么錯。

Answer 1

嘗試將MyApplication從com.johndoe.myapp移至com.johndoe類應類似於：

package com.johndoe;

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

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

確保您的依賴@SpringBootApplication中沒有其他帶有注解@SpringBootApplication類：

compile project(':<other folder in MyProject>')

春天開機可以找到這個類，並用它來掃描（ @SpringBootApplication注釋包含@ComponentScan 。的默認行為@ComponentScan是相同的封裝和注解類的所有子包中尋找類）