如何使用Java Spring Boot创建随机唯一ID？

问题描述 投票：0回答：2

我有一个具有以下属性的技能实体；

@Id
    @GeneratedValue (strategy=GenerationType.IDENTITY)
    @Column(name = "idskill", nullable = false) 
    private int idskill;

    private String skillName;

我希望在创建新条目时为ID分配一个随机值，理想情况下会自动递增。然后，我尝试使用一种方法将新条目保存到mysql数据库中；

Optional<Skill> skill=skillRepository.findByskillName(skillName);
        int id=0;
        if(skill.isPresent()) {
            id=Integer.valueOf(skill.get().getIdSkill());
        }
        else {
            Skill newSkill = new Skill();
            newSkill.setSkillName(skillName);
            skillRepository.save(newSkill);
        }

但是，我收到此错误；

java.sql.SQLException: Field 'idskill' doesn't have a default value
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:953) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1092) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1040) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeLargeUpdate(ClientPreparedStatement.java:1347) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdate(ClientPreparedStatement.java:1025) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61) ~[HikariCP-3.4.1.jar:na]
    at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java) ~[HikariCP-3.4.1.jar:na]
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:197) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.dialect.identity.GetGeneratedKeysDelegate.executeAndExtract(GetGeneratedKeysDelegate.java:57) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:43) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3106) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3699) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:84) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:645) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:282) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:263) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:317) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:335) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:292) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:198) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:128) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:192) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:135) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:62) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:108) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:702) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:688) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_241]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_241]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_241]
    at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:368) ~[spring-orm-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at com.sun.proxy.$Proxy81.persist(Unknown Source) ~[na:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_241]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_241]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_241]
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:314) ~[spring-orm-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at com.sun.proxy.$Proxy81.persist(Unknown Source) ~[na:na]
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:554) ~[spring-data-jpa-2.2.3.RELEASE.jar:2.2.3.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_241]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_241]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_241]
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:371) ~[spring-data-commons-2.2.3.RELEASE.jar:2.2.3.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:204) ~[spring-data-commons-2.2.3.RELEASE.jar:2.2.3.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:657) ~[spring-data-commons-2.2.3.RELEASE.jar:2.2.3.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:621) ~[spring-data-commons-2.2.3.RELEASE.jar:2.2.3.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:605) ~[spring-data-commons-2.2.3.RELEASE.jar:2.2.3.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80) ~[spring-data-commons-2.2.3.RELEASE.jar:2.2.3.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:366) ~[spring-tx-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:99) ~[spring-tx-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:178) ~[spring-data-jpa-2.2.3.RELEASE.jar:2.2.3.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at com.sun.proxy.$Proxy87.save(Unknown Source) ~[na:na]
    at main.CSVController.findSkill(CSVController.java:128) ~[classes/:na]
    at main.CSVController.importRoles(CSVController.java:109) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_241]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_241]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_241]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) ~[spring-webmvc-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888) ~[spring-webmvc-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1591) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [na:1.8.0_241]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [na:1.8.0_241]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.29.jar:9.0.29]
    at java.lang.Thread.run(Unknown Source) [na:1.8.0_241]

有人知道为什么会这样吗？如果不需要，我不想从sql workbench更改数据库。我想知道我是否缺少默认值属性，但似乎无法在线找到任何东西

java mysql spring-boot save auto-increment
2个回答
0
投票

这将为您生成一个随机的唯一ID

import java.util.UUID;  
public class UniqueIDTest {  
 public static void main(String[] args) {  
  UUID uniqueKey = UUID.randomUUID();   
  System.out.println (uniqueKey);  
}  
}
0
投票

问题是您将列指定为不可为空，因此，如果未显式填充id字段，则hibernate将拒绝您的操作。

如下进行更改应可解决问题。 GenerationType.AUTO将让数据库负责ID的生成。

@Id
@GeneratedValue (strategy=GenerationType.AUTO)
@Column(name = "idskill") 
private int idskill;
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