Spring-boot CrudRepository自动装配错误

Question

我有我的Springboot应用程序的following code structure：

我对bean NoSuchBeanDefinitionException的{​​{1}}例外。

异常追踪：

UserDao

UserDao.java接口的源代码是

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.matlb.dao.UserDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotat`enter code here`ion.Autowired(required=true)}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1373) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1119) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:545) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    ... 37 common frames omitted

我在这里自动装配

package com.matlb.dao;

import com.matlb.domain.User;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface UserDao extends CrudRepository<User,Integer>{

    User findByEmail(String email);
}

主类来源

package com.matlb.service;

import com.matlb.dao.UserDao;
import com.matlb.domain.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    @Override
    public List<User> findAll() {
        return (List<User>) getUserDao().findAll();
    }

    @Override
    public User createUser(String email) {
        User user = new User(email);
        return saveUser(user);
    }

    @Override
    public User findById(Integer userId) {
        return getUserDao().findOne(userId);
    }

    @Override
    public User saveUser(User user) {
        return getUserDao().save(user);
    }

    @Override
    public User findByEmail(String email) {
        return getUserDao().findByEmail(email);
    }

    @Override
    public void delete(Integer userId) {
        getUserDao().delete(userId);
    }

    public UserDao getUserDao() {
        return userDao;
    }
}

build.gradle

package com.matlb;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@SpringBootApplication
public class MatlbApplication {

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

请让我知道我做错了什么。我使用Intellij作为IDE，并在使用buildscript { ext { springBootVersion = '1.3.3.RELEASE' } repositories { mavenCentral() } dependencies { classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}") classpath("org.springframework:springloaded:1.2.1.RELEASE") } } apply plugin: 'java' apply plugin: 'eclipse' apply plugin: 'idea' apply plugin: 'spring-boot' jar { baseName = 'demo' version = '0.0.1-SNAPSHOT' } sourceCompatibility = 1.8 targetCompatibility = 1.8 repositories { mavenCentral() } dependencies { compile('org.springframework.boot:spring-boot-starter-aop') compile('org.springframework.boot:spring-boot-starter-web') compile("org.springframework.boot:spring-boot-devtools") compile("org.springframework.boot:spring-boot-starter-data-jpa") runtime('mysql:mysql-connector-java') testCompile('org.springframework.boot:spring-boot-starter-test') testCompile('org.springframework.restdocs:spring-restdocs-mockmvc') } idea { module { inheritOutputDirs = false outputDir = file("$buildDir/classes/main/") } } eclipse { classpath { containers.remove('org.eclipse.jdt.launching.JRE_CONTAINER') containers 'org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8' } } task wrapper(type: Wrapper) { gradleVersion = '2.9' } 注释时创建了显示bean。

Answer 1

首先，您需要从DAO界面中删除@Repository。 Spring Data JPA将构建实现并将其部署在Spring容器中，而不使用@Repository。 @EnableJpaRepository将向String Data Jpa发出指令。 Spring Boot自动配置将为您声明@ EnableJpaRepository`。

然后，用JpaRepository替换CrudRepository。

最后，请确保已将spring-boot-starter-data-jpa声明为maven依赖项。

此致 丹尼尔

Answer 2

命名并正确放置包装， com.app-SpringBootApplication com.app.controller-控制器类 com.app.repo-Repo类超出了CrudRepository com.app.model-您的表类（实体）

Answer 3

@Daniel已经为Spring Data连接存储库提供了很好的背景知识。

对于调试，由于某种原因，Spring无法初始化从CrudRepository扩展的存储库时不显示任何错误。要进行调试，请将扩展类从CrudRepository更改为JpaRepository。现在，Spring将说明为什么它不能初始化存储库（在我的情况下，这是该实体未正确映射到表）。解决这些错误后，您可以切换回CrudRepository。它将起作用。它对我有用。