spring - Springboot:需要一个找不到的“javax.persistence.EntityManagerFactory”类型的bean
问题描述
我正在开发 Spring Boot 应用程序并在启动服务器时遇到此错误。我不确定我是否错误地定义了任何注释或缺少任何依赖项。任何帮助,将不胜感激。
主类:
@SpringBootApplication
@Configuration
@ComponentScan
@EnableAutoConfiguration
public class DemoApplication {
public static void main(String[] args) {
System.out.println("Hello world");
SpringApplication.run(DemoApplication.class, args);
}
}
用户服务类:
@Service
public class UserService implements IUserService {
@Autowired
private UserDAO userDAO;
@Override
public List<UserDTO> getAllUsers() {
List<User> entities = userDAO.getUsers();
List<UserDTO> users = new ArrayList<UserDTO>();//Will never use directly User Object, will be using Tranferable objects
Iterator<User> iterator = entities.iterator();
while(iterator.hasNext()) {
User user = iterator.next();
users.add(ApiDTOBuilder.userToUserDTO(user));//We are building UserDTO object.
}
return users;
}
@Override
public UserDTO getUserByUsername(String username) {
User user = userDAO.getUser(username);
return ApiDTOBuilder.userToUserDTO(user);
}
@Override
public void createUser(UserDTO user) {
userDAO.createUser(ApiDTOBuilder.userDTOToUser(user));
}
@Override
public void updateUser(UserDTO user) {
userDAO.updateUser(ApiDTOBuilder.userDTOToUser(user));
}
@Override
public void deleteUser(String username) {
userDAO.deleteUser(username);
}
}
UserDAO 类:
@Repository 公共类 UserDAO 实现 IUserDAO {
@PersistenceContext
EntityManager em;//JPA EntityManager is used to access a database in a particular application. It is used to manage persistent entity instances, to find entities by their primary key identity(As here is Username), and to query over all entities.
@Override
@Transactional
public User getUser(String username) {
return em.find(User.class, username); //Here entitymanager can find the username as it has the capability to find an entity by unique identifies
}
@Override
@Transactional
public List<User> getUsers() {
List<User> resultList = em.createQuery("FROM user_tbl", User.class).getResultList();
return resultList;
}
@Override
@Transactional
public void createUser(User user) {
em.persist(user);//Make an instance managed and persistent.
}
@Override
@Transactional
public void updateUser(User user) {
em.merge(user);//Merge the state of the given entity into the current persistence context.
}
@Override
@Transactional
public void deleteUser(String username) {
User user = this.getUser(username);
em.remove(user);//Remove the entity instance.
}
}
构建.gradle:
buildscript {
ext {
springBootVersion = '2.0.0.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
dependencies {
compile('org.springframework.boot:spring-boot-starter-data-jpa')
compile('org.springframework.boot:spring-boot-starter-web')
compile('org.springframework.boot:spring-boot-starter-security')
compile('org.hibernate.javax.persistence:hibernate-jpa-2.1-api:1.0.0.Final')
compile('javax.xml.bind:jaxb-api:2.2.11')
compile('org.springframework.boot:spring-boot-starter-test:2.0.2.RELEASE')
compile('com.sun.xml.bind:jaxb-core:2.2.11')
compile('com.sun.xml.bind:jaxb-impl:2.2.11')
runtime('org.springframework.boot:spring-boot-devtools')
runtime('mysql:mysql-connector-java')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
错误信息:
***************************
APPLICATION FAILED TO START
***************************
Description:
Field userDAO in com.example.demo.service.UserService required a bean of type 'javax.persistence.EntityManagerFactory' that could not be found.
Action:
Consider defining a bean of type 'javax.persistence.EntityManagerFactory' in your configuration.
我看到了所有相关的答案并尝试实施这些建议,例如添加依赖项、在主类中添加符号等。但它显示了相同的错误。请有人帮助我。先感谢您。
PS:我的应用程序的 Github 链接:https ://github.com/heliOpenxCell/demo
解决方案
我遇到了同样的问题,只需将其添加到您的 Maven 或 gradle 中,它对我有用!
马文:
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-jdbc</artifactId>
<version>9.0.10</version>
</dependency>
摇篮:
compile group: 'org.apache.tomcat', name: 'tomcat-jdbc', version: '9.0.10'
推荐阅读
- arrays - 如何将变量从测试传递到 beforeEach 钩子?
- amazon-web-services - 云(Azure、AWS)中磁盘上的内容在重新发布给其他用户之前是否已归零?
- computer-science - 扩展名前文件名中的点(。)的目的是什么。它是某种运算符吗?
- scala - 使用 Gatling 进行慢速负载测试
- ios - UITableView - 在 Xamarin 中动画插入行
- ansible - Ansible lineinfile 在编辑前添加新行
- c# - 使用 Expression.Lambda 制作 lambda 表达式时如何使用变量
>() - java - Spring Boot ConfigurationProperties - 未映射基类
- c# - C# - 测量经过时间的最有效方法
- python - 带有 CSV 的 Jinja2 模板中的 For 循环