java 运行SpringBoot & POSTMAN时出现状态500错误“内部服务器错误”

tjvv9vkg  于 2023-01-24  发布在  Java
关注(0)|答案(3)|浏览(779)

我是SpringBoot和Postman的新手，刚开始学习Java，我正在学习教程，但在SpringBoot上运行文件后，当我尝试使用POSTMAN * POST * 时，总是收到以下错误：

我已经仔细检查了数据库，运行良好，我也没有得到任何错误的SpringBoot。
来自SpringBoot的日志：

2023-01-20T17:57:07.313Z[0;39m [31mERROR[0;39m [35m8208[0;39m [2m---[0;39m [2m[nio-8080-exec-5][0;39m [36mo.a.c.c.C.[.[.[/].[dispatcherServlet]   [0;39m [2m:[0;39m Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: org.springframework.dao.DataIntegrityViolationException: not-null property references a null or transient value : com.advanced.app1.model.Employee.firstName] with root cause

org.hibernate.PropertyValueException: not-null property references a null or transient value : com.advanced.app1.model.Employee.firstName
    at org.hibernate.engine.internal.Nullability.checkNullability(Nullability.java:111) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.engine.internal.Nullability.checkNullability(Nullability.java:55) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.action.internal.AbstractEntityInsertAction.nullifyTransientReferencesIfNotAlready(AbstractEntityInsertAction.java:119) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:68) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:653) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:283) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:264) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:322) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:340) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:286) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:192) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:122) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:184) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:129) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:53) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:107) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:737) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:721) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[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:568) ~[na:na]
    at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:360) ~[spring-orm-6.0.4.jar:6.0.4]
    at jdk.proxy2/jdk.proxy2.$Proxy96.persist(Unknown Source) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[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:568) ~[na:na]
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:307) ~[spring-orm-6.0.4.jar:6.0.4]
    at jdk.proxy2/jdk.proxy2.$Proxy96.persist(Unknown Source) ~[na:na]
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:610) ~[spring-data-jpa-3.0.1.jar:3.0.1]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[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:568) ~[na:na]
    at org.springframework.data.repository.core.support.RepositoryMethodInvoker$RepositoryFragmentMethodInvoker.lambda$new$0(RepositoryMethodInvoker.java:288) ~[spring-data-commons-3.0.1.jar:3.0.1]
    at org.springframework.data.repository.core.support.RepositoryMethodInvoker.doInvoke(RepositoryMethodInvoker.java:136) ~[spring-data-commons-3.0.1.jar:3.0.1]
    at org.springframework.data.repository.core.support.RepositoryMethodInvoker.invoke(RepositoryMethodInvoker.java:120) ~[spring-data-commons-3.0.1.jar:3.0.1]
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:516) ~[spring-data-commons-3.0.1.jar:3.0.1]
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:285) ~[spring-data-commons-3.0.1.jar:3.0.1]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:628) ~[spring-data-commons-3.0.1.jar:3.0.1]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.4.jar:6.0.4]
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:168) ~[spring-data-commons-3.0.1.jar:3.0.1]
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:143) ~[spring-data-commons-3.0.1.jar:3.0.1]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.4.jar:6.0.4]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:77) ~[spring-data-commons-3.0.1.jar:3.0.1]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.4.jar:6.0.4]
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123) ~[spring-tx-6.0.4.jar:6.0.4]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388) ~[spring-tx-6.0.4.jar:6.0.4]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-6.0.4.jar:6.0.4]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.4.jar:6.0.4]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137) ~[spring-tx-6.0.4.jar:6.0.4]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.4.jar:6.0.4]
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:163) ~[spring-data-jpa-3.0.1.jar:3.0.1]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.4.jar:6.0.4]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97) ~[spring-aop-6.0.4.jar:6.0.4]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.4.jar:6.0.4]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:218) ~[spring-aop-6.0.4.jar:6.0.4]
    at jdk.proxy2/jdk.proxy2.$Proxy100.save(Unknown Source) ~[na:na]
    at com.advanced.app1.service.impl.EmployeeServiceImpl.saveEmployee(EmployeeServiceImpl.java:21) ~[classes/:na]
    at com.advanced.app1.controller.EmployeeController.saveEmployee(EmployeeController.java:27) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[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:568) ~[na:na]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:207) ~[spring-web-6.0.4.jar:6.0.4]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:152) ~[spring-web-6.0.4.jar:6.0.4]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-6.0.4.jar:6.0.4]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:884) ~[spring-webmvc-6.0.4.jar:6.0.4]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-6.0.4.jar:6.0.4]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-6.0.4.jar:6.0.4]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1080) ~[spring-webmvc-6.0.4.jar:6.0.4]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:973) ~[spring-webmvc-6.0.4.jar:6.0.4]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1011) ~[spring-webmvc-6.0.4.jar:6.0.4]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:914) ~[spring-webmvc-6.0.4.jar:6.0.4]
    at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:731) ~[tomcat-embed-core-10.1.5.jar:6.0]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885) ~[spring-webmvc-6.0.4.jar:6.0.4]
    at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:814) ~[tomcat-embed-core-10.1.5.jar:6.0]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:223) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-6.0.4.jar:6.0.4]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.0.4.jar:6.0.4]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-6.0.4.jar:6.0.4]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.0.4.jar:6.0.4]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-6.0.4.jar:6.0.4]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.0.4.jar:6.0.4]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:177) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:119) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:400) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:859) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1734) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-10.1.5.jar:10.1.5]
    at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]
{
     "timestamp": "2023-01-20T12:47:38.113+00:00", 
     "status": 500, 
     "error": "Internal Server Error", 
     "path": "/api/employees" 
 }

我的pom.xml文件：

<?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 https://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>3.0.1</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.advanced</groupId>
    <artifactId>sprintboot-advanced</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>sprintboot-advanced</name>
    <description>Sprinboot Advanced</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <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>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</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>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

主要：

package com.advanced.app1;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SprintbootAdvanced1Application {

    public static void main(String[] args) {
        SpringApplication.run(SprintbootAdvanced1Application.class, args);
    }

}

控制器：

package com.advanced.app1.controller;

import org.springframework.http.HttpStatus; 
import org.springframework.http.ResponseEntity;
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 com.advanced.app1.model.Employee;
import com.advanced.app1.service.EmployeeService;

@RestController
@RequestMapping("/api/employees")
public class EmployeeController {
    
    private EmployeeService employeeService;

    public EmployeeController(EmployeeService employeeService) {
        super();
        this.employeeService = employeeService;
    }
    
    // build REST API
    @PostMapping()
    public ResponseEntity<Employee> saveEmployee(@RequestBody Employee employee){
        return new ResponseEntity<Employee>(employeeService.saveEmployee(employee), HttpStatus.CREATED);
    }
}

例外情况：

package com.advanced.app1.exception;

import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ResponseStatus;

@ResponseStatus(value = HttpStatus.NOT_FOUND)
public class ResourceNotFoundException extends RuntimeException{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private String resourceName;
    private String fieldName;
    private Object fieldValue;
    
    public ResourceNotFoundException(String resourceName, String fieldName, Object fieldValue) {
        super(String.format("%s not found with %s : '%s'", resourceName, fieldName, fieldValue));
        this.resourceName = resourceName;
        this.fieldName = fieldName;
        this.fieldValue = fieldValue;
    }
    
    public String getResourceName() {
        return resourceName;
    }
    
    public String getFieldName() {
        return fieldName;
    }
    
    public Object getFieldValue() {
        return fieldValue;
    }   
}

型号：

package com.advanced.app1.model;

import jakarta.persistence.Column;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.Table;
import lombok.Data;

@Data
@Entity
@Table(name="employees")
public class Employee {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;
    
    @Column(name = "first_name", nullable = false)
    private String firstName;
    
    @Column(name = "last_name")
    private String lastName;
    
    @Column(name = "email")
    private String email;
}

储存库：

package com.advanced.app1.repository;

import org.springframework.data.jpa.repository.JpaRepository;   
import com.advanced.app1.model.Employee;

public interface EmployeeRepository extends JpaRepository<Employee, Long> {

}

服务：

package com.advanced.app1.service;

import com.advanced.app1.model.Employee;

public interface EmployeeService {

    Employee saveEmployee(Employee employee);
}

服务实施：

package com.advanced.app1.service.impl;

import org.springframework.stereotype.Service;  
import com.advanced.app1.model.Employee;
import com.advanced.app1.repository.EmployeeRepository;
import com.advanced.app1.service.EmployeeService;

@Service
public class EmployeeServiceImpl implements EmployeeService{

    private EmployeeRepository employeeRepository;
    
    public EmployeeServiceImpl(EmployeeRepository employeeRepository) {
        super();
        this.employeeRepository = employeeRepository;
    }

    @Override
    public Employee saveEmployee(Employee employee) {
        return employeeRepository.save(employee);
    }

}

application.properties：

spring.datasource.url=jdbc:mysql://localhost:3306/test?useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.properties.hibernate.dialect= org.hibernate.dialect.MySQLDialect
spring.jpa.hibernate.ddl-auto = update

请求和返回的标头POSTMAN：

Java

3条答案

按热度按时间
brgchamk

brgchamk1#

你说你没有在Sping Boot 日志中发现错误，但是你发布了一个堆栈跟踪，这是你所能期望的最好的错误类型，事实上，它确切地告诉你问题是什么：
org.hibernate.PropertyValueException:非空属性引用空值或 transient 值：com.advanced.app1.model.Employee.firstName
您的实体未将“firstName”标记为可空

@Column(name = "first_name", nullable = false)

不知何故，Employee实体没有被POST请求中的数据填充，如果反序列化不能“自动”从JSON字段Map到Employee对象字段，就会发生这种情况。
一个可能的原因是你没有在你的实体上定义任何getter或setter，我看到你在使用lombok，但我建议至少现在排除任何与Spring框架不兼容的问题，直接手动生成这些方法。
您还可以直接从REST API写入数据库实体。虽然这不是一个严格的问题，但这不是一个最佳实践，有时会导致奇怪的行为。我建议创建一个专门用于REST接口的模型对象（POJO），然后Map到Repository中的实体。

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zc0qhyus

zc0qhyus2#

状态500“内部服务器错误”是一个常规错误消息，它表示应用程序的服务器端出现了问题。此错误可能有多种原因，但一些常见原因包括：
配置问题：检查应用程序的配置（如属性文件），以确保一切设置正确。
编码错误：这可能是代码中的错误，导致服务器崩溃或返回错误。请检查语法错误、空指针异常和其他常见编码问题。
数据库问题：请确保数据库正在运行且配置正确。检查数据库连接设置并确保正确的用户有权访问数据库。
依赖性问题：如果您正在使用任何依赖项或库，请确保它们是最新的并且与您的应用程序兼容。
权限问题：检查运行应用程序的用户是否具有访问所需资源的正确权限。
建议检查服务器日志以查看有关错误的更多详细信息，这可以帮助您确定问题的根本原因并进行修复。
值得一提的是，使用Postman测试您的应用程序并不能揭示所有可能的问题，因此，通过直接在浏览器或其他客户机上运行应用程序来测试您的应用程序是值得的。

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rqcrx0a6

rqcrx0a63#

问题的原因：

{
    "timestamp": "2023-01-22T14:43:44.841+00:00",
    "status": 500,
    "error": "Internal Server Error",
    "path": "/api/employees"
}

如前所述，Hypino位于您提供的entity中：

@Data
@Entity
@Table(name="employees")
public class Employee {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;
    
    @Column(name = "first_name", nullable = false)
    private String firstName;
    
    @Column(name = "last_name")
    private String lastName;
    
    @Column(name = "email")
    private String email;
}

这 * 意味着 * 您将first_name标记为不能拥有null，因此Spring不能将json请求Map到对象，因此first_name始终为null。
在您的情况下：
nullable = false表示此值不能为null。

@Column(name = "first_name", nullable = false)

这意味着在为表创建模式时，它将使用名称"first_name"作为名称，而name = "firstName", nullable = false意味着在保存到数据库时，如果值为null，它将不保存并抛出异常：

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: org.springframework.dao.DataIntegrityViolationException: not-null property references a null or transient value

如果您查看生成的实际sql。
同时，@Column只关心数据库，所以当您通过Rest API调用它时，Spring只关心变量名，而不关心列名。
因此，您有 * 几个 * 选项如何处理它，这真的取决于您和您的项目要求：

    • 选项1**

(To* 明确 * 使用nullable = true作为选项）

@Data
@Entity
@Table(name = "employees")
public class Employee {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;

    @Column(name = "first_name", nullable = true)
    private String first_name;

    @Column(name = "last_name", nullable = true)
    private String last_name;

    @Column(name = "email", nullable = true)
    private String email;
}

根据Postman中的body为：

{
    "first_name": "testFirstName",
    "last_name": "testLastName",
    "email": "testEmail@gmail.com"
}

优点

  • 你可以马上看到它是可以为空的，这在你直接从github分析代码或者你不知道默认值的时候会很有用。
  • 如果默认值发生变化，您可以设置它，而不必担心它。
    *缺点：
  • 默认值更改的可能性非常非常小
  • 它使代码更冗长，这通常是不受欢迎的。

true是nullable的默认选项，因此可以省略。如果没有带名称的@Column注解，Hibernate将使用字段名称创建一个列，将camel-case替换为snake-case。
如果你喜欢把事情说清楚-好吧。

    • 选项2**

(To避免使用注解：@Column(name = "first_name", nullable = false用于特定字段，如下所附）
Controller类：

@RestController
@RequestMapping("/api/employees")
public class EmployeeController {

    private EmployeeService employeeService;

    public EmployeeController(EmployeeService employeeService) {
        this.employeeService = employeeService;
    }

    @PostMapping
    public ResponseEntity<Employee> saveEmployee(@RequestBody Employee employee){
        return new ResponseEntity<>
                (employeeService.saveEmployee(employee), HttpStatus.CREATED);
    }
}

ResourceNotFoundException类：

@ResponseStatus(value = HttpStatus.NOT_FOUND)
public class ResourceNotFoundException extends RuntimeException {

    private static final long serialVersionUID = 1L;
    private String resourceName;
    private String fieldName;
    private Object fieldValue;

    public ResourceNotFoundException(String resourceName, String fieldName, Object fieldValue) {
        super(String.format("%s not found with %s : '%s'", resourceName, fieldName, fieldValue));
        this.resourceName = resourceName;
        this.fieldName = fieldName;
        this.fieldValue = fieldValue;
    }

    public String getResourceName() {
        return resourceName;
    }

    public String getFieldName() {
        return fieldName;
    }

    public Object getFieldValue() {
        return fieldValue;
    }
}

Model类：

@Data
@Entity
@Table(name = "employees")
public class Employee {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;

    private String firstName;

    private String lastName;

    private String email;
}

Repository：

public interface EmployeeRepository extends JpaRepository<Employee, Long> {

}

Service实施（* 业务逻辑 *）：

@Service
public class EmployeeServiceImpl implements EmployeeService {

    private final EmployeeRepository employeeRepository;

    public EmployeeServiceImpl(EmployeeRepository employeeRepository) {
        super();
        this.employeeRepository = employeeRepository;
    }

    @Override
    public Employee saveEmployee(Employee employee) {
        return employeeRepository.save(employee);
    }
}

Service：

public interface EmployeeService {

    Employee saveEmployee(Employee employee);
}

Main类：

@SpringBootApplication
public class SpringBootAdvancedApplication {

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

以及相应的database配置：

spring.datasource.url=jdbc:mysql://localhost:3306/testdb?useSSL=false&allowPublicKeyRetrieval=true
spring.datasource.username=root
spring.datasource.password=...
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQLDialect
spring.jpa.hibernate.ddl-auto=update

因此，您可以使用POST请求通过Postman进行测试，如下所示：

http://localhost:8080/api/employees

使用body，如示例所示：

{
    "firstName": "testFirstName",
    "lastName": "testLastName",
    "email": "testEmail@gmail.com"
}

选择raw和JSON作为您的选项。

  • 请求的标题 *：

POM文件的内容：

<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>
        <version>3.0.1</version>
    </dependency>

    <dependency>
        <groupId>com.mysql</groupId>
        <artifactId>mysql-connector-j</artifactId>
        <scope>runtime</scope>
    </dependency>

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-tomcat</artifactId>
        <scope>provided</scope>
    </dependency>

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

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

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>10</source>
                <target>10</target>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <excludes>
                    <exclude>
                        <groupId>org.projectlombok</groupId>
                        <artifactId>lombok</artifactId>
                    </exclude>
                </excludes>
            </configuration>
        </plugin>
    </plugins>
</build>

如果你在知道默认值的时候更喜欢避免样板文件--也可以。这里的关键是在整个项目中保持规则的一致性。
其他 * 有用 * 和 * 信息丰富 * 的链接：

  1. Hibernate Tips: What’s the difference between @Column(nullable = false) and @NotNull
  2. Hibernate @NotNull vs @Column(nullable = false)
  3. Hibernate handling of nullable=true in @Column
  4. Does it make sense to write @Column(nullable = true) for entity while using Hibernate?
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