Java 考虑在您的配置中定义一个类型的 bean
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Consider defining a bean of type in your configuration
提问by Chase
I am following this tutorial ( https://www.youtube.com/watch?v=Hu-cyytqfp8) and trying to connect to MongoDB on a remote server in Spring Boot. I get the following message when I run the application.
我正在关注本教程 ( https://www.youtube.com/watch?v=Hu-cyytqfp8) 并尝试在 Spring Boot 的远程服务器上连接到 MongoDB。我在运行应用程序时收到以下消息。
Description: Parameter 0 of constructor in com.mongotest.demo.Seeder required a bean of type 'com.mongotest.repositories.StudentRepository' that could not be found.
Action: Consider defining a bean of type 'com.mongotest.repositories.StudentRepository' in your configuration.
说明：com.mongotest.demo.Seeder 中构造函数的参数 0 需要一个无法找到的类型为“com.mongotest.repositories.StudentRepository”的 bean。
行动：考虑在你的配置中定义一个“com.mongotest.repositories.StudentRepository”类型的bean。
The project structure.
项目结构。
And here are my classes
这是我的课程
@Document(collection = "Students")
public class Student {
@Id
private String number;
private String name;
@Indexed(direction = IndexDirection.ASCENDING)
private int classNo;
//Constructor and getters and setters.
}
================================
@Repository
public interface StudentRepository extends MongoRepository<Student, String>{
}
================================
@Component
@ComponentScan({"com.mongotest.repositories"})
public class Seeder implements CommandLineRunner{
private StudentRepository studentRepo;
public Seeder(StudentRepository studentRepo) {
super();
this.studentRepo = studentRepo;
}
@Override
public void run(String... args) throws Exception {
// TODO Auto-generated method stub
Student s1 = new Student("1","Tom",1);
Student s2 = new Student("2","Jerry",1);
Student s3 = new Student("3","Kat",2);
studentRepo.deleteAll();
studentRepo.save(Arrays.asList(s1,s2,s3));
}
}
================================
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
pom.xml
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>com.mongotest</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.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.mongodb</groupId>
<artifactId>mongo-java-driver</artifactId>
<version>3.4.2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</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>
采纳答案by Saravana
Please add below annotations in DemoApplication
请在下面添加注释 DemoApplication
@SpringBootApplication
@ComponentScan("com.mongotest") //to scan packages mentioned
@EnableMongoRepositories("com.mongotest") //to activate MongoDB repositories
public class DemoApplication { ... }
回答by Ankit Kumar
If you wish to avoid writing annotations you can simply change your packages com.mongotest.entities to com.mongotest.demo.entities and com.mongotest.repositories to com.mongotest.demo.repositories
如果您希望避免编写注释，您可以简单地将包 com.mongotest.entities 更改为 com.mongotest.demo.entities 并将 com.mongotest.repositories 更改为 com.mongotest.demo.repositories
Spring Boot architecture will take care of rest. Actually other files and packages are supposed to be either at same level or below your DemoApplication.java.
Spring Boot 架构将负责休息。实际上，其他文件和包应该与您的 DemoApplication.java 处于同一级别或以下。
回答by Saurabh
In my case , I was getting same error using mysql db
就我而言，我在使用 mysql db 时遇到了同样的错误
solved using @EnableJpaRepositories
使用@EnableJpaRepositories解决
@SpringBootApplication
@ComponentScan("com.example.repositories")//to scan repository files
@EntityScan("com.example.entities")
@EnableJpaRepositories("com.example.repositories")
public class EmployeeApplication implements CommandLineRunner{ ..}
回答by Sushrut Kanetkar
I have 3 helper classes RedisManager, JWTTokenCreator & JWTTokenReader which I needed to pass in constructor as dependency of SessionService spring service.
我有 3 个帮助类 RedisManager、JWTTokenCreator 和 JWTTokenReader，我需要将它们作为 SessionService spring 服务的依赖项传入构造函数。
@SpringBootApplication
@Configuration
public class AuthenticationServiceApplication {
@Bean
public SessionService sessionService(RedisManager redisManager, JWTTokenCreator tokenCreator, JWTTokenReader tokenReader) {
return new SessionService(redisManager,tokenCreator,tokenReader);
}
@Bean
public RedisManager redisManager() {
return new RedisManager();
}
@Bean
public JWTTokenCreator tokenCreator() {
return new JWTTokenCreator();
}
@Bean
public JWTTokenReader JWTTokenReader() {
return new JWTTokenReader();
}
public static void main(String[] args) {
SpringApplication.run(AuthenticationServiceApplication.class, args);
}
}
The service class is as follows
服务类如下
@Service
@Component
public class SessionService {
@Autowired
public SessionService(RedisManager redisManager, JWTTokenCreator
tokenCreator, JWTTokenReader tokenReader) {
this.redisManager = redisManager;
this.tokenCreator = tokenCreator;
this.jwtTokenReader = tokenReader;
}
}
回答by rahul tiwari
@Document(collection = "Students")
public class Student {
@Id
private String number;
private String name;
@Indexed(direction = IndexDirection.ASCENDING)
private int classNo;
//Constructor and getters and setters.
}
================================
@Repository
public interface StudentRepository extends MongoRepository<Student, String>{
}
================================
@Component
@ComponentScan({"com.mongotest.repositories"})
public class Seeder implements CommandLineRunner{
private StudentRepository studentRepo;
public Seeder(StudentRepository studentRepo) {
super();
this.studentRepo = studentRepo;
}
@Override
public void run(String... args) throws Exception {
// TODO Auto-generated method stub
Student s1 = new Student("1","Tom",1);
Student s2 = new Student("2","Jerry",1);
Student s3 = new Student("3","Kat",2);
studentRepo.deleteAll();
studentRepo.save(Arrays.asList(s1,s2,s3));
}
}
================================
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}回答by Dheeraj
The problem here is with the annotation you defined.
这里的问题在于您定义的注释。
@ComponentScan("com.mongotest")
@ComponentScan("com.mongotest")
This will scan all the relevant packages under the project structure 'com.mongotest' and initializes the beans in all the subpackage classes.
这将扫描项目结构“com.mongotest”下的所有相关包，并初始化所有子包类中的 bean。
