Spring Data Repository - 没有合格的 bean 注入答案

【问题标题】：Spring Data Repository - No qualifying bean InjectionSpring Data Repository - 没有合格的 bean 注入
【发布时间】：2015-02-24 13:46:24
【问题描述】：

我是 Spring 框架的新手。我刚开始学习各种指南 (http://spring.io/guides)，我正在尝试完成有关 Web 服务的完整教程 (http://spring.io/guides/tutorials/bookmarks/)。

我非常卡在 JPA 数据源定义上，因为我收到以下错误

Exception in thread "main" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'init' defined in main.Application: Unsatisfied dependency expressed through constructor argument with index 0 of type [bookmarks.AccountRepository]: : No qualifying bean of type [bookmarks.AccountRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [bookmarks.AccountRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:749)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:464)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1111)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1006)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:762)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:691)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:321)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:961)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:950)
    at main.Application.main(Application.java:41)
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [bookmarks.AccountRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1308)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1054)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:949)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:813)
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741)
    ... 18 more

我的主要应用程序类如下

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {

    @Bean
    public CommandLineRunner init(AccountRepository accountRepository,
            BookmarkRepository bookmarkRepository) {
        System.out.println("Bean!");
        return (evt) -> Arrays.asList(
                "jhoeller,dsyer,pwebb,ogierke,rwinch,mfisher,mpollack,jlong".split(","))
                .forEach(
                        a -> {
                            Account account = accountRepository.save(new Account(a,
                                    "password"));
                            bookmarkRepository.save(new Bookmark(account,
                                    "http://bookmark.com/1/" + a, "A description"));
                            bookmarkRepository.save(new Bookmark(account,
                                    "http://bookmark.com/2/" + a, "A description"));
                        });
    }

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

而我的 pom.xml 是

<?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>org.test</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1</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>1.2.1.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <start-class>demo.DemoApplication</start-class>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <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>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
        </dependency>
        <dependency>
            <groupId>javax.inject</groupId>
            <artifactId>javax.inject</artifactId>
            <version>1</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

我了解到依赖注入框架没有找到 AccountRepository 接口的任何实现，看起来像

public interface AccountRepository extends JpaRepository<Account, Long> {
    Optional<Account> findByUsername(String username);
}

但框架应该为 JpaRepository 提供“正确的实现”。这是我不理解的部分。

任何帮助都将不胜感激，特别是提供深入研究此框架的指针。

谢谢

更新将 @EnableJpaRepositories("bookmarks") 添加到 Application 类，解决了 bean 解析问题。但现在我明白了原因：java.lang.IllegalArgumentException：不是托管类型：class bookmarks.Account

我的 Account 实体类是

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;

import com.fasterxml.jackson.annotation.JsonIgnore;

@Entity
public class Account {

    @JsonIgnore
    public String password;
    public String username;
    @OneToMany(mappedBy="Account") 
    private Set<Bookmark> bookmarks = new HashSet<>();
    @Id @GeneratedValue 
    private Long id;

    public Account(String name, String password) {
        this.username = name;
        this.password = password;
    }

    Account() { } // jpa only

    // getters and setters
}

【问题讨论】：

你的仓库在哪些包中？
我的项目结构如下： src/main/java 书签 Account.java AccountRepository.java main Application.java 所以存储库在包书签中。
ID 下载源代码并从那里开始工作 - github.com/spring-guides/tut-bookmarks/blob/master/rest/src/… - 帮助不大 - 但您正在学习本教程
谢谢，我已经探索了那个仓库，但没有成功:(

标签： java spring dependency-injection spring-data-jpa autowired

【解决方案1】：

要让框架选择 JpaRepository，您需要在配置中启用它 - 添加

@EnableJpaRepositories("your.package.with.jpa.repositories")

在您的 @Configuration 文件中。

更新

这里是 jpa 存储库工作的示例配置：

@Bean
public DataSource dataSource(){
    // configure your datasource
}

@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory(DataSource dataSource) {
    LocalContainerEntityManagerFactoryBean emfb = new LocalContainerEntityManagerFactoryBean();
    emfb.setDataSource(dataSource);
    emfb.setPackagesToScan("your.package.with.model"); 
    emfb.setJpaVendorAdapter(jpaVendorAdapter());
    emfb.setJpaPropertyMap(jpaPropertiesMap()); 
    return emfb;
}

@Bean 
public JpaVendorAdapter jpaVendorAdapter() {
    return new HibernateJpaVendorAdapter();
}

@Bean
public PlatformTransactionManager transactionManager(EntityManagerFactory emf) {
    JpaTransactionManager transactionManager = new JpaTransactionManager();
    transactionManager.setEntityManagerFactory(emf);
    return transactionManager;
}

public Map<String, ?> jpaPropertiesMap() {
    Properties properties = new Properties();
    properties.setProperty("hibernate.dialect", "org.hibernate.dialect.H2Dialect"); // assumption based on your pom-file
    properties.setProperty("hibernate.hbm2ddl.auto", "..."); // you need to google for appropriate option
    return properties;
}

【讨论】：

感谢您的回复。我在主类“Application”上添加了@EnableJpaRepositories("bookmarks") 注释，但现在我收到以下错误 java.lang.IllegalArgumentException: Not an managed type: class bookmarks.Account。 account 类是一个@Entity 注解的类
@besil 好吧，因为您使用的是 JpaRepository，所以您的 Account 必须是 jpa 实体。它应该用 @Entity 注释并有一个 id 属性 - 用 @Id 注释。
是的。 bean 实体解析现在似乎工作了，但我不明白为什么 Account 类会抛出错误
@besil 你的项目中配置了 jpa 提供者吗？
抱歉，我不知道。我该如何检查？你能指点我一些文件吗？谢谢！

【解决方案2】：

解决问题的最终（工作）配置如下（仅遵循文档http://spring.io/guides/tutorials/bookmarks/）。

解决方案正在添加

<dependency>
  <groupId>com.h2database</groupId>
  <artifactId>h2</artifactId>
</dependency>

在 pom.xml 中，并更改

@OneToMany(mappedBy = "account")
private Set<Bookmark> bookmarks = new HashSet<>();

在 Account 类中（错误是：mappedBy="Account"，大写字母...）。

完整代码如下：

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>org.test</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

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

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <start-class>demo.MyRestServiceApplication</start-class>
        <java.version>1.8</java.version>
    </properties>

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

帐户类

package bookmarks;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;

import com.fasterxml.jackson.annotation.JsonIgnore;

@Entity
public class Account {

    @OneToMany(mappedBy = "account")
    private Set<Bookmark> bookmarks = new HashSet<>();

    @Id
    @GeneratedValue
    private Long id;

    public Set<Bookmark> getBookmarks() {
        return bookmarks;
    }

    public Long getId() {
        return id;
    }

    public String getPassword() {
        return password;
    }

    public String getUsername() {
        return username;
    }

    @JsonIgnore
    public String password;
    public String username;

    public Account(String name, String password) {
        this.username = name;
        this.password = password;
    }

    Account() { // jpa only
    }
}

应用类

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {
    @Bean
    CommandLineRunner init(AccountRepository accountRepository,
            BookmarkRepository bookmarkRepository) {
        return (evt) -> Arrays.asList(
                "jhoeller,dsyer,pwebb,ogierke,rwinch,mfisher,mpollack,jlong".split(","))
                .forEach(
                        a -> {
                            Account account = accountRepository.save(new Account(a,
                                    "password"));
                            bookmarkRepository.save(new Bookmark(account,
                                    "http://bookmark.com/1/" + a, "A description"));
                            bookmarkRepository.save(new Bookmark(account,
                                    "http://bookmark.com/2/" + a, "A description"));
                        });
    }

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

【讨论】：