java Spring boot - 使用 JPA 在关系数据库中存储和检索数据时出现 UnsatisfiedDependencyException
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时间：2020-11-02 23:51:02 来源:igfitidea点击:
Spring boot - UnsatisfiedDependencyException when using JPA to store and retrieve data in a relational database
提问by Declan Fitzpatrick
I've tried to build an application that uses Spring Data JPA to store and retrieve data in a relational database using Spring boot. I've been following guide on the spring site but continue to get this error. Does anyone know the cause of this or what I could do to fix it? Would be much appreciated, thanks.
我尝试构建一个应用程序，该应用程序使用 Spring Data JPA 在使用 Spring boot 的关系数据库中存储和检索数据。我一直在遵循 spring 站点上的指南，但继续收到此错误。有谁知道这是什么原因或我能做些什么来解决它？将不胜感激，谢谢。
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'commandLine' defined in com.example.Application: Unsatisfied dependency expressed through constructor argument with index 0 of type [com.example.ImageRepository]: : Error creating bean with name 'imageRepository': Cannot create inner bean '(inner bean)#391c56d7' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#391c56d7': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'entityManagerFactory' is defined; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'imageRepository': Cannot create inner bean '(inner bean)#391c56d7' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#391c56d7': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'entityManagerFactory' is defined
The code is below:
代码如下：
The repository:
存储库：
package com.example;
import java.util.List;
import org.springframework.data.repository.CrudRepository;
public interface ImageRepository extends CrudRepository<Image, Long> {
List<Image> findByImageID(long imageID);
}
The application:
应用程序：
@SpringBootApplication
public class Application {
private static final Logger log = LoggerFactory.getLogger(Application.class);
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
@Bean
public CommandLineRunner commandLine(ImageRepository repository) {
return (args) -> {
repository.save(new Image("image1",50,40));
repository.save(new Image("image2",50,40));
repository.save(new Image("image3",50,40));
repository.save(new Image("image4",50,40));
repository.save(new Image("image5",50,40));
log.info("Customers found with findAll():");
log.info("-------------------------------");
for (Image image : repository.findAll()) {
log.info(image.toString());
}
log.info("");
Image image = repository.findOne(1L);
log.info("Image found with findOne(1L):");
log.info("--------------------------------");
log.info(image.toString());
log.info("");
log.info("Image found with findByImageID(1):");
log.info("--------------------------------------------");
for (Image im : repository.findByImageID(1)) {
log.info(im.toString());
}
log.info("");
};
}
}
The entity
实体
@Entity
public class Image {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private long imageID;
private double lat, lon;
private String description = "";
protected Image() {}
Image(String description, double lat, double lon)
{
this.description = description;
this.lat = lat;
this.lon = lon;
}
Image(double lat, double lon)
{
this.lat = lat;
this.lon = lon;
}
public long getID()
{
return imageID;
}
public String getDesc()
{
return description;
}
public double getLat()
{
return lat;
}
public double getLon()
{
return lon;
}
@Override
public String toString() {
return String.format(
"Image[id=%d, description='%s', lat='%d', lon='%d']",
imageID, description,lat,lon);
}
}
POM
聚甲醛
<?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>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</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>1.3.2.RELEASE</version>
<relativePath/>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<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.thymeleaf</groupId>
<artifactId>thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf-spring4</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>persistence-api</artifactId>
<version>1.0.2</version>
</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>
回答by romixch
Now I had the time to test it on my machine. The problem is that you are missing a jpa implementation. By adding a dependency to spring-data-jpa and and persistence-api you only get the interfaces. If you replace those two dependencies with spring-boot-starter-data-jpa, you will actually get a hibernate entitymanager implementation.
现在我有时间在我的机器上测试它。问题是您缺少 jpa 实现。通过向 spring-data-jpa 和 persistence-api 添加依赖项，您只能获得接口。如果你用 spring-boot-starter-data-jpa 替换这两个依赖项，你实际上会得到一个 hibernate entitymanager 实现。
This is the pom.xml I successfully tested:
这是我测试成功的 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>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</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>1.3.2.RELEASE</version>
<relativePath/>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<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.thymeleaf</groupId>
<artifactId>thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf-spring4</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</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>
