Java Spring RestFul API答案

【问题标题】：Java Spring RestFull APIJava Spring RestFul API
【发布时间】：2019-05-30 02:03:25
【问题描述】：

我正在尝试学习如何在 java 中使用 restful 服务。但我遇到了这个我似乎无法弄清楚的问题。我正在尝试调用此控制器，它将获取数据并将其存储在数据库中。但我得到的例外是我以前没有遇到过的。如果我删除模型类作为参数并尝试只返回一个基本字符串，它工作正常。但我的目标是将传递给控制器的任何数据存储在数据库中。

enter code here

person.java // 模型类

@Entity
@Table(name = "Person")
@EntityListeners(AuditingEntityListener.class)
@JsonIgnoreProperties(value = {"createdAt", "updatedAt"}, allowGetters = true)

public class Person implements Serializable {

    @JsonProperty("key")
    public int getKey() {
        return key;
    }

    public void setKey(int key) {
        this.key = key;
    }


    @JsonProperty("name")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    @JsonProperty("m")
    public int getMotherKey() {
        return motherKey;
    }
    public void setMotherKey(int motherKey) {
        this.motherKey = motherKey;
    }
    @JsonProperty("f")
    public int getFatherKey() {
        return fatherKey;
    }
    public void setFatherKey(int fatherKey) {
        this.fatherKey = fatherKey;
    }

    @JsonProperty("dob")
    public int getDateOfBirth() {
        return DateOfBirth;
    }
    public void setDateOfBirth(int dateOfBirth) {
        DateOfBirth = dateOfBirth;
    }

    @JsonProperty("g")
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }



    public Person() {



    }


    @NotNull
    int key;    
    @NotBlank
    String name;
    @NotNull
    int motherKey;
    @NotNull
    int fatherKey;
    @NotNull
    int DateOfBirth; //19921210->December 10th 1992 
    @NotBlank
    String gender;

**控制器类**

package com.example.FamilyTree;
import java.util.List;
import javax.validation.Valid;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import Repository.TreeRepository;
import exception.ResourceNotFoundException;
import model.Person;




@RestController
@RequestMapping("/api")
public class FamilityTreeController {


    TreeRepository  treeRepository;



    @PostMapping("/addPerson")
    public Person addPerson(@Valid @RequestBody Person person) {


        return treeRepository.save( person);

    }
}

例外在

com.example.FamilyTree.FamilityTreeController.addPerson(FamilityTreeController.java:32) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) ~[spring-webmvc-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:791) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135) [na:na]
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [na:na]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.13.jar:9.0.13]
    at java.base/java.lang.Thread.run(Thread.java:844) [na:na]

存储库

package Repository;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.jpa.repository.JpaRepository;

import model.Person;


public interface TreeRepository extends JpaRepository<Person, Integer> {



}

来自 Postman 的完整堆栈跟踪

{
    "timestamp": "2019-01-03T14:06:28.971+0000",
    "status": 500,
    "error": "Internal Server Error",
    "message": "No message available",
    "trace": "java.lang.NullPointerException\n\tat com.example.FamilyTree.FamilityTreeController.addPerson(FamilityTreeController.java:27)\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)\n\tat java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n\tat java.base/java.lang.reflect.Method.invoke(Method.java:564)\n\tat org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189)\n\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)\n\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800)\n\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)\n\tat org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908)\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:660)\n\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:741)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)\n\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)\n\tat org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)\n\tat org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)\n\tat org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:791)\n\tat org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417)\n\tat org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)\n\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\n\tat java.base/java.lang.Thread.run(Thread.java:844)\n",
    "path": "/api/addPerson"
}

**FamilyTreeApplication 类**

package com.example.FamilyTree;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;

import controller.FamilityTreeController;

@SpringBootApplication
@EnableJpaAuditing
public class FamilyTreeApplication {
    public static void main(String[] args) {
        SpringApplication.run(FamilyTreeApplication.class, args);
    }

}

更新包结构

**cmd **

 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaAuditingHandler': Cannot resolve reference to bean 'jpaMappingContext' while setting constructor argument; nested exception is 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.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:378) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:110) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:662) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:188) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1308) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1154) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:846) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863) ~[spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546) ~[spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) ~[spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
        at com.example.FamilyTree.FamilyTreeApplication.main(FamilyTreeApplication.java:22) [classes/:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
        at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.1.1.RELEASE.jar:2.1.1.RELEASE]
    Caused by: 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:1745) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:576) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:367) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        ... 26 common frames omitted
    Caused by: java.lang.IllegalArgumentException: At least one JPA metamodel must be present!
        at org.springframework.util.Assert.notEmpty(Assert.java:464) ~[spring-core-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.data.jpa.mapping.JpaMetamodelMappingContext.<init>(JpaMetamodelMappingContext.java:57) ~[spring-data-jpa-2.1.3.RELEASE.jar:2.1.3.RELEASE]
        at org.springframework.data.jpa.repository.config.JpaMetamodelMappingContextFactoryBean.createInstance(JpaMetamodelMappingContextFactoryBean.java:80) ~[spring-data-jpa-2.1.3.RELEASE.jar:2.1.3.RELEASE]
        at org.springframework.data.jpa.repository.config.JpaMetamodelMappingContextFactoryBean.createInstance(JpaMetamodelMappingContextFactoryBean.java:44) ~[spring-data-jpa-2.1.3.RELEASE.jar:2.1.3.RELEASE]
        at org.springframework.beans.factory.config.AbstractFactoryBean.afterPropertiesSet(AbstractFactoryBean.java:142) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1804) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1741) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
        ... 33 common frames omitted

【问题讨论】：

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标签： java spring maven jpa

【解决方案1】：

问题是 treeRepository 不是 Spring 注入的，因此是 null。

首先，通过将 @EnableJpaRepositories(basePackages = "<package of your repository interface>")) 添加到 Spring 配置类 (FamilyTreeApplication) 来确保正确配置了 TreeRepository。

然后要正确注入它，您应该添加@Autowired 注释：

@Autowired
private TreeRepository treeRepository;

或者将其注入构造函数中，这是 Spring 团队的首选方式。

private TreeRepository treeRepository;

//@Autowired not needed, implicit as of Spring 4.3
public FamilityTreeController(TreeRepository treeRepository) {
  this.treeRepository = treeRepository;
}

你的包层次结构也有一些问题可能会影响 Spring Boot 如何找到组件：你的主配置类 (FamilyTreeApplication) 应该位于应用程序“基础包”和子包中的所有其他类中，有些像这样：

com.example.familytree
|_ FamilyTreeApplication.java
|_ controller
   |_ FamilyTreeController.java
|_ repository
   |_ TreeRepositry.java
...

【讨论】：

@al_khalid 我没有按照我的建议在您的配置类中看到 @EnableJpaRepositories。

【解决方案2】：

最好使用服务类

这个注解作为@Component 的一个特化，允许通过类路径扫描自动检测实现类。

@Service
public class TreeService {
      @Autowired
      TreeRepository treeRepository;

      public Person save(Person person) {
         return treeRepository.save(person);
      }
}

将您的控制器类更改为：

@RestController
@RequestMapping("/api")
public class FamilityTreeController {

@Autowired 
TreeService  treeService;

@PostMapping("/addPerson")
public Person addPerson(@Valid @RequestBody Person person) {
    return treeService.save( person);
   }
}

请将包名改为小写，并按照naming convention：

将这个：Repository.TreeRepository 改成这个：com.example.repository.TreeRepository 以及其他人：com.example.model.Personcom.example.exception.ResourceNotFoundException

【讨论】：

org.springframework.beans.factory.UnsatisfiedDependencyException：创建名为“familityTreeController”的bean时出错：通过字段“treeService”表示的依赖关系不满足；嵌套异常是 org.springframework.beans.factory.NoSuchBeanDefinitionException：没有“com.example.services.TreeService.TreeService”类型的合格 bean 可用：预计至少有 1 个有资格作为自动装配候选者的 bean。依赖注解：{@org.springframework.beans.factory.annotation.Autowired(required=true)}
编译时出现以下异常
com.example.services.TreeService.TreeService 我希望你已经创建了一个名为com.example.services.TreeService 和TressService 的java类在里面。
最好使用小写的包命名约定。大写用于类名。
我建议您遵循本教程。很老但是很适合学习 Spring Boot youtube.com/watch?v=msXL2oDexqw

【解决方案3】：

您的存储库中缺少@Repository 注释：

@Repository
public interface TreeRepository extends JpaRepository<Person, Integer> { }

并记得添加@Autowired 以注入存储库：

    @Autowired
    private TreeRepository treeRepository;

更新

即使添加了@Repository，Spring 似乎也无法找到该 bean。我建议您将所有包放在com.example 下，并添加一个引用该包的component scan 配置。

【讨论】：

添加@autowired 导致以下异常嵌套异常是 org.springframework.beans.factory.NoSuchBeanDefinitionException：没有“respository.TreeRepository”类型的合格 bean 可用：预计至少有 1 个有资格作为自动装配候选者的 bean。依赖注解：{@org.springframework.beans.factory.annotation.Autowired(required=true)}
您是否在项目中使用任何类型的组件扫描？请在问题中发布它，似乎即使添加了@Repository Spring 也无法看到它
您不需要在 Spring Data 中添加 @Repository 注释。确保您的 JpaRepository 配置正确（请参阅我的答案）
@ngueno 组件扫描默认使用 Spring Boot 完成，但它不会找到存储库，因为它应该首先由 Spring Data 生成（并且已经在 Spring 上下文中）
SpringBootApplication 注释包括@ComponentScan（除其他外），如果您不指定任何基本包，它将从配置类的包中扫描。但是添加它并没有什么坏处，因为 Spring Boot 会自动执行很多事情，以至于初级开发人员很难理解幕后发生的事情。