在基本 Spring-MVC（非引导）项目中访问@Autowired 存储库 (JPA) 时出现问题
problem accessing @Autowired repository (JPA) in basic Spring-MVC (non-boot) project
我设置了一个非常基本的 spring-mvc 项目（非引导）以通过 JPA 访问我的数据库。但我不断得到：
UnsatisfiedDependencyException
NoSuchBeanDefinitionException
这是应用程序无法找到并初始化的结果
@Autowired
private UserRepository repo;
我想根据this tutorial设置JPA。没有初始化 UserRepository，应用程序工作正常。
谁能帮帮我？我浏览了上千个教程，其中大部分是 Spring Boot 应用程序，此时我不想使用 Spring Boot。如何正确设置？
这是我的代码，该项目是在 IntelliJ 中创建的，使用 maven-archetype-webapp 并具有以下配置：
ApplicationConfig.java
package dominikazb.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;
import java.util.Properties;
@Configuration
@EnableTransactionManagement
@ComponentScan(basePackages = "dominikazb")
public class ApplicationConfig extends WebMvcConfigurationSupport {
@Bean
public InternalResourceViewResolver jspViewResolver(){
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/jsp/");
viewResolver.setSuffix(".jsp");
viewResolver.setViewClass(JstlView.class);
return viewResolver;
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
LocalContainerEntityManagerFactoryBean em
= new LocalContainerEntityManagerFactoryBean();
em.setDataSource(dataSource());
em.setPackagesToScan(new String[] { "dominikazb" });
JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
em.setJpaVendorAdapter(vendorAdapter);
em.setJpaProperties(additionalProperties());
return em;
}
@Bean
public DataSource dataSource(){
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
dataSource.setUrl("jdbc:mysql://database_hosted_on_heroku");
dataSource.setUsername( "username" );
dataSource.setPassword( "password" );
return dataSource;
}
@Bean
public PlatformTransactionManager transactionManager(EntityManagerFactory emf) {
JpaTransactionManager transactionManager = new JpaTransactionManager();
transactionManager.setEntityManagerFactory(emf);
return transactionManager;
}
@Bean
public PersistenceExceptionTranslationPostProcessor exceptionTranslation(){
return new PersistenceExceptionTranslationPostProcessor();
}
Properties additionalProperties() {
Properties properties = new Properties();
properties.setProperty("hibernate.hbm2ddl.auto", "create-drop");
properties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect");
return properties;
}
}
User.java
package dominikazb.beans;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class User {
@Id
private int user_id;
private String username;
private String password;
public int getUser_id() {
return user_id;
}
public void setUser_id(int user_id) {
this.user_id = user_id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User{" +
"user_id=" + user_id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
HomeController.java
package dominikazb.controllers;
import dominikazb.repositories.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
public class HomeController {
@Autowired
private UserRepository repo;
@RequestMapping(value = "/", method = RequestMethod.GET)
public String takeMeHome() {
return "index";
}
@RequestMapping(value = "/list", method = RequestMethod.GET)
public String searchDatabase() {
return "list";
}
}
UserRepository.java
package dominikazb.repositories;
import dominikazb.beans.User;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
@Repository
public interface UserRepository extends CrudRepository <User, Integer> {
}
pom.xml
<dependencies>
<!-- https://mvnrepository.com/artifact/javax/javaee-web-api -->
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-web-api</artifactId>
<version>8.0</version>
<scope>provided</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.3.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
<version>8.0.19</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.1.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>5.1.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-jpa</artifactId>
<version>2.1.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.4.1.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.4.2.Final</version>
<scope>runtime</scope>
</dependency>
应用-context.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="dominikazb" />
<mvc:annotation-driven />
</beans>
web.xml
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/application-context.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
完全异常：
Type Exception Report
Message Servlet.init() for servlet [dispatcher] threw exception
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
javax.servlet.ServletException: Servlet.init() for servlet [dispatcher] threw exception
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1598)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.base/java.lang.Thread.run(Thread.java:834)
Root Cause
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'homeController': Unsatisfied dependency expressed through field 'repo'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'dominikazb.repositories.UserRepository' 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.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:643)
org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:116)
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=20=](AbstractBeanFactory.java:323)
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879)
org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863)
org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:702)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:668)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:716)
org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:591)
org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:530)
org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:170)
javax.servlet.GenericServlet.init(GenericServlet.java:158)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1598)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.base/java.lang.Thread.run(Thread.java:834)
Root Cause
org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'dominikazb.repositories.UserRepository' 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.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1695)
org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1253)
org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207)
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640)
org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:116)
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=20=](AbstractBeanFactory.java:323)
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879)
org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863)
org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:702)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:668)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:716)
org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:591)
org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:530)
org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:170)
javax.servlet.GenericServlet.init(GenericServlet.java:158)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1598)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.base/java.lang.Thread.run(Thread.java:834)
Note The full stack trace of the root cause is available in the server logs.
CrudRepository 是@NoRepositoryBean，您不需要在UserRepository 上添加@Repository。
将以下内容添加到您的配置文件中，如果 spring-data-jpa 在您的 Maven 依赖项中不可用，则将其添加到您的 pom.xml、
@EnableJpaRepositories(basePackages= {"dominikazb.repositories"})
我设置了一个非常基本的 spring-mvc 项目（非引导）以通过 JPA 访问我的数据库。但我不断得到：
UnsatisfiedDependencyException
NoSuchBeanDefinitionException
这是应用程序无法找到并初始化的结果
@Autowired
private UserRepository repo;
我想根据this tutorial设置JPA。没有初始化 UserRepository，应用程序工作正常。
谁能帮帮我？我浏览了上千个教程，其中大部分是 Spring Boot 应用程序，此时我不想使用 Spring Boot。如何正确设置？
这是我的代码，该项目是在 IntelliJ 中创建的，使用 maven-archetype-webapp 并具有以下配置：
ApplicationConfig.java
package dominikazb.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;
import java.util.Properties;
@Configuration
@EnableTransactionManagement
@ComponentScan(basePackages = "dominikazb")
public class ApplicationConfig extends WebMvcConfigurationSupport {
@Bean
public InternalResourceViewResolver jspViewResolver(){
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/jsp/");
viewResolver.setSuffix(".jsp");
viewResolver.setViewClass(JstlView.class);
return viewResolver;
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
LocalContainerEntityManagerFactoryBean em
= new LocalContainerEntityManagerFactoryBean();
em.setDataSource(dataSource());
em.setPackagesToScan(new String[] { "dominikazb" });
JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
em.setJpaVendorAdapter(vendorAdapter);
em.setJpaProperties(additionalProperties());
return em;
}
@Bean
public DataSource dataSource(){
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
dataSource.setUrl("jdbc:mysql://database_hosted_on_heroku");
dataSource.setUsername( "username" );
dataSource.setPassword( "password" );
return dataSource;
}
@Bean
public PlatformTransactionManager transactionManager(EntityManagerFactory emf) {
JpaTransactionManager transactionManager = new JpaTransactionManager();
transactionManager.setEntityManagerFactory(emf);
return transactionManager;
}
@Bean
public PersistenceExceptionTranslationPostProcessor exceptionTranslation(){
return new PersistenceExceptionTranslationPostProcessor();
}
Properties additionalProperties() {
Properties properties = new Properties();
properties.setProperty("hibernate.hbm2ddl.auto", "create-drop");
properties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect");
return properties;
}
}
User.java
package dominikazb.beans;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class User {
@Id
private int user_id;
private String username;
private String password;
public int getUser_id() {
return user_id;
}
public void setUser_id(int user_id) {
this.user_id = user_id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User{" +
"user_id=" + user_id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
HomeController.java
package dominikazb.controllers;
import dominikazb.repositories.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
public class HomeController {
@Autowired
private UserRepository repo;
@RequestMapping(value = "/", method = RequestMethod.GET)
public String takeMeHome() {
return "index";
}
@RequestMapping(value = "/list", method = RequestMethod.GET)
public String searchDatabase() {
return "list";
}
}
UserRepository.java
package dominikazb.repositories;
import dominikazb.beans.User;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
@Repository
public interface UserRepository extends CrudRepository <User, Integer> {
}
pom.xml
<dependencies>
<!-- https://mvnrepository.com/artifact/javax/javaee-web-api -->
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-web-api</artifactId>
<version>8.0</version>
<scope>provided</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.3.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
<version>8.0.19</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.1.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>5.1.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-jpa</artifactId>
<version>2.1.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.4.1.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.4.2.Final</version>
<scope>runtime</scope>
</dependency>
应用-context.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="dominikazb" />
<mvc:annotation-driven />
</beans>
web.xml
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/application-context.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
完全异常：
Type Exception Report
Message Servlet.init() for servlet [dispatcher] threw exception
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
javax.servlet.ServletException: Servlet.init() for servlet [dispatcher] threw exception
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1598)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.base/java.lang.Thread.run(Thread.java:834)
Root Cause
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'homeController': Unsatisfied dependency expressed through field 'repo'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'dominikazb.repositories.UserRepository' 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.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:643)
org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:116)
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=20=](AbstractBeanFactory.java:323)
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879)
org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863)
org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:702)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:668)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:716)
org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:591)
org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:530)
org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:170)
javax.servlet.GenericServlet.init(GenericServlet.java:158)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1598)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.base/java.lang.Thread.run(Thread.java:834)
Root Cause
org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'dominikazb.repositories.UserRepository' 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.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1695)
org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1253)
org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207)
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640)
org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:116)
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=20=](AbstractBeanFactory.java:323)
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879)
org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863)
org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:702)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:668)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:716)
org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:591)
org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:530)
org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:170)
javax.servlet.GenericServlet.init(GenericServlet.java:158)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1598)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.base/java.lang.Thread.run(Thread.java:834)
Note The full stack trace of the root cause is available in the server logs.
CrudRepository 是@NoRepositoryBean，您不需要在UserRepository 上添加@Repository。
将以下内容添加到您的配置文件中，如果 spring-data-jpa 在您的 Maven 依赖项中不可用，则将其添加到您的 pom.xml、
@EnableJpaRepositories(basePackages= {"dominikazb.repositories"})