Spring boot Field 需要一个找不到类型的 bean

Question

我正在努力学习 spring boot 的 JPA 入门教程。我知道这里有时会问这个问题（ “字段需要一个无法找到的类型的 bean”。错误 spring restful API using mongodb ）

但这些问题与我遇到的有点不同。

结构

java
  |
  helloWorld
  |
  web/ -- HelloWorldController
  Application
  Customer
  CustomerRepository
  ServletInitializer

如您所见，我所有与 JPA 相关的包都与我的应用程序文件处于同一级别。根据教程（ https://spring.io/guides/gs/accessing-data-jpa/ ），这应该可以工作

我的应用类

package helloWorld;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
public class Application extends SpringBootServletInitializer {

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

    @Autowired
    CustomerRepository customerRepository;

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Application.class);
    }
}

客户资料库

package helloWorld;

import org.springframework.data.repository.CrudRepository;

import java.util.List;

public interface CustomerRepository extends CrudRepository<Customer, Long> {

    List<Customer> findByLastName(String lastName);
}

当尝试使用 @Autowired 我收到

***************************
APPLICATION FAILED TO START
***************************

Description:

Field customerRepository in helloWorld.Application required a bean of type 'helloWorld.CustomerRepository' that could not be found.

Action:

Consider defining a bean of type 'helloWorld.CustomerRepository' in your configuration.

此外，将 scanBasePackages={"helloWorld"}) 添加到 @SpringBootApplication 没有帮助，从我读到的内容来看，也不需要。

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>helloWorld.com.example</groupId>
    <artifactId>helloWorld</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>fireCommerce</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</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>
            <plugin>
                <groupId>com.microsoft.azure</groupId>
                <artifactId>azure-webapp-maven-plugin</artifactId>
                <version>1.1.0</version>
                <configuration>
                    <resourceGroup>maven-projects</resourceGroup>
                    <appName>${project.artifactId}-${maven.build.timestamp}</appName>
                    <region>westus</region>
                    <javaVersion>1.8</javaVersion>
                    <deploymentType>war</deploymentType>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

链接到github项目

原文由 xhallix 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

您正在排除 JPA 存储库的自动配置。从 application.properties 中删除该行，让 Spring CustomerRepository 一个 bean 并对其进行配置。

 spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration

原文由 Andrew Tobilko 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

就我而言，我只是忘记将 @Component 添加到接口的 Impl 类中！

这些错误可能是由于缺少一个或多个 原型注释 造成的。

原文由 Demobilizer 发布，翻译遵循 CC BY-SA 4.0 许可协议