IllegalArgumentException：必须存在至少一个JPA元模型

Question

在开始使用spring rest时，我得到了如下错误

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaMappingContext': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: At least one JPA metamodel must be present! at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1595) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:566) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:725) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866) ~[spring-context-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:736) [spring-boot-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:369) [spring-boot-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT] at org.springframework.boot.SpringApplication.run(SpringApplication.java:313) [spring-boot-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1161) [spring-boot-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1150) [spring-boot-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT] at com.java.app.QuickPollApplication.main(QuickPollApplication.java:14) [classes/:na] Caused by: java.lang.IllegalArgumentException: At least one JPA metamodel must be present! at org.springframework.util.Assert.notEmpty(Assert.java:438) ~[spring-core-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.data.jpa.mapping.JpaMetamodelMappingContext.(JpaMetamodelMappingContext.java:52) ~[spring-data-jpa-1.11.0.BUILD-SNAPSHOT.jar:na] at org.springframework.data.jpa.repository.config.JpaMetamodelMappingContextFactoryBean.createInstance(JpaMetamodelMappingContextFactoryBean.java:71) ~[spring-data-jpa-1.11.0.BUILD-SNAPSHOT.jar:na] at org.springframework.data.jpa.repository.config.JpaMetamodelMappingContextFactoryBean.createInstance(JpaMetamodelMappingContextFactoryBean.java:26) ~[spring-data-jpa-1.11.0.BUILD-SNAPSHOT.jar:na] at org.springframework.beans.factory.config.AbstractFactoryBean.afterPropertiesSet(AbstractFactoryBean.java:134) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1654) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1591) ~[spring-beans-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT] ... 16 common frames omitted

用下面的代码

@SpringBootApplication
@RestController
public class QuickPollApplication {

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

    @RequestMapping(value = "/test", method = RequestMethod.GET)
    public String testRest() {
        return "rest tested";
    }

以下是我的pom.xml

UTF-8 UTF-8 1.8

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web-services</artifactId>
        </dependency>

        <dependency>
            <groupId>org.hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </pluginRepository>
        <pluginRepository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

请帮我。我不知道如何解决这个错误

Answer 1

你已添加

<dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

在你的pom.xml中。

Spring Boot会尝试自动为JPA创建实体工厂，但是你尚未定义有关JPA模型的任何内容。

尝试将其删除，以测试到目前为止你做了什么。