[英]Java Spring Boot: Consider defining a bean named 'entityManagerFactory' in your configuration
[英]Consider defining a bean of type EntityManagerFactory Spring boot
我正在使用Spring Boot並在此錯誤中運行:
組件需要找不到類型為'javax.persistence.EntityManagerFactory'的bean。
行動:
考慮在配置中定義類型為javax.persistence.EntityManagerFactory的bean。
我不知道我該怎么做,因為我會根據課程來做所有事情
我用@PersistanceUnit注入EntityManagerFactory
<?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>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>pl.javastart</groupId>
<artifactId>spring-jpa-boot2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>spring-jpa-boot2</name>
<description>Spring boot app</description>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</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>
package pl.javastart.dao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Repository;
import pl.javastart.model.Book;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.PersistenceUnit;
@Repository
public class BookDaoImpl implements BookDao {
@PersistenceUnit
private EntityManagerFactory emFactory;
public BookDaoImpl(){
}
@Override
public void save(Book book) {
EntityManager entityManager = emFactory.createEntityManager();
EntityTransaction tx = entityManager.getTransaction();
tx.begin();
entityManager.persist(book);
tx.commit();
entityManager.close();
}
@Override
public Book get(Long id) {
EntityManager entityManager = emFactory.createEntityManager();
Book book = entityManager.find(Book.class, id);
entityManager.close();
return book;
}
}
package pl.javastart;
import org.springframework.boot.SpringApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import pl.javastart.dao.BookDao;
import pl.javastart.model.Book;
@Configuration
@ComponentScan
public class SpringJpaApplication {
public static void main(String[] args) throws InterruptedException {
ConfigurableApplicationContext ctx = SpringApplication.run(SpringJpaApplication.class, args);
BookDao dao = ctx.getBean(BookDao.class);
Book book = new Book("1234567890468", "Spring is so cool", "Javastart");
dao.save(book);
Thread.sleep(5000);
}
}
我該如何解決?
您的配置在JPA服務器配置和Spring Boot之間是固定的。
在Spring Boot中,您需要創建將由所有應用程序使用的數據源bean。 通常,您既不需要使用EntityManager,也不需要使用EntityManagerFactory,這是因為服務器和Spring數據都將創建它們,並且只需要使用由Spring和將要實現的服務創建的存儲庫。
這是Spring Boot應用程序的常規配置。
@Configuration
@EnableAutoConfiguration
@ComponentScan(basePackages = {"package.where.are.your.repositorios.and.services"})
@EntityScan(basePackages = "package.where.are.your.entities")
@EnableJpaRepositories(basePackages = "package.where.are.your.repositories", entityManagerFactoryRef = "entityManagerFactory")
@EnableTransactionManagement
public class RepositoryConfiguration {
@Bean
public DataSource jndiDataSource() throws IllegalArgumentException, NamingException {
// Here you can create your datasource using application.properties configuration or inject the datasource from the server application.
JndiObjectFactoryBean bean = new JndiObjectFactoryBean();
bean.setJndiName("JNDI_IN_YOUR_SERVER");
bean.setProxyInterface(DataSource.class);
bean.setLookupOnStartup(true);
bean.afterPropertiesSet();
return (DataSource) bean.getObject();
}
}
這是Spring Data的經典配置,使您能夠實現存儲庫。
一個存儲庫示例:
@Repository
public interface BuserRepository extends JpaRepository<Buser, Long> {
@Query("SELECT t FROM Buser t WHERE t.username = :username")
Optional<Buser> findByUsername(@Param("username") String username);
}
如果要在數據庫中保存一些新對象或更新,則所有這些都已在Spring的JpaRepository類中實現,或者還有其他要擴展的類。
請在此處閱讀有關此內容的更多信息:
我向Maven添加了兩個特權:
<dependency>
<groupId>javax.xml.bind</groupId>
<artifactId>jaxb-api</artifactId>
<version>2.4.0-b180830.0359</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>4.3.8.Final</version>
</dependency>
一切正常
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