我有一个旧项目，我在其中使用来自 Java API 的日期，我想将其更改为新的 Java 8 Date API to LocalDateTime。我读到 Hibernate 5 之前的版本不支持新的 Java 8 Date API，因此我决定从 Hibernate 4.3.6 迁移到 5。在旧项目版本中一切正常，但是当我更改 Hibernate 版本时，出现错误我尝试启动我的应用程序:
wrz 21, 2015 7:14:23 PM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jre1.8.0_31\bin;C:\windows\Sun\Java\bin;C:\windows\system32;C:\windows;C:/Program Files/Java/jre1.8.0_31/bin/server;C:/Program Files/Java/jre1.8.0_31/bin;C:/Program Files/Java/jre1.8.0_31/lib/amd64;D:\oraclexe\app\oracle\product\11.2.0\server\bin;;C:\ProgramData\Oracle\Java\javapath;D:\oraclexe\app\oracle\product\11.2.0\server\bin;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files\Common Files\Microsoft Shared\Windows Live;C:\Program Files (x86)\Common Files\Microsoft Shared\Windows Live;C:\windows\system32;C:\windows;C:\windows\System32\Wbem;C:\windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\WIDCOMM\Bluetooth Software\;C:\Program Files\WIDCOMM\Bluetooth Software\syswow64;C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\;C:\Program Files\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files (x86)\Microsoft SDKs\TypeScript\1.0\;D:\Program Files\eclipse;;.
wrz 21, 2015 7:14:23 PM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:iBank' did not find a matching property.
wrz 21, 2015 7:14:23 PM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.j2ee.server:webClient' did not find a matching property.
wrz 21, 2015 7:14:24 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-8181"]
wrz 21, 2015 7:14:24 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
wrz 21, 2015 7:14:24 PM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 1096 ms
wrz 21, 2015 7:14:24 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
wrz 21, 2015 7:14:24 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.47
wrz 21, 2015 7:14:25 PM org.apache.catalina.util.SessionIdGenerator createSecureRandom
INFO: Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [161] milliseconds.
wrz 21, 2015 7:14:30 PM org.apache.catalina.core.ApplicationContext log
INFO: No Spring WebApplicationInitializer types detected on classpath
INFO : org.springframework.web.context.ContextLoader - Root WebApplicationContext: initialization started
wrz 21, 2015 7:14:30 PM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring root WebApplicationContext
INFO : org.springframework.web.context.support.XmlWebApplicationContext - Refreshing Root WebApplicationContext: startup date [Mon Sep 21 19:14:31 CEST 2015]; root of context hierarchy
INFO : org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loading XML bean definitions from ServletContext resource [/WEB-INF/spring/root-context.xml]
INFO : org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loading XML bean definitions from ServletContext resource [/WEB-INF/spring/security-config.xml]
INFO : org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor - JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
ERROR: org.springframework.web.context.ContextLoader - Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in ServletContext resource [/WEB-INF/spring/root-context.xml]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: iBankPU] Unable to build Hibernate SessionFactory
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1553)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:973)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:750)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4939)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5434)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: iBankPU] Unable to build Hibernate SessionFactory
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.persistenceException(EntityManagerFactoryBuilderImpl.java:877)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:805)
at org.hibernate.jpa.HibernatePersistenceProvider.createContainerEntityManagerFactory(HibernatePersistenceProvider.java:135)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:336)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1612)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1549)
... 21 more
Caused by: org.hibernate.tool.schema.spi.SchemaManagementException: Unable to execute schema management to JDBC target [alter table transfers add constraint FK1vp11ydp2tn6fufhmfcr2is8x foreign key (fromAccId) references usersAccounts]
at org.hibernate.tool.schema.internal.TargetDatabaseImpl.accept(TargetDatabaseImpl.java:59)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.applySqlString(SchemaMigratorImpl.java:371)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.applySqlStrings(SchemaMigratorImpl.java:360)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.applyForeignKeys(SchemaMigratorImpl.java:325)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.doMigrationToTargets(SchemaMigratorImpl.java:157)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.doMigration(SchemaMigratorImpl.java:59)
at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:129)
at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:97)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:481)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:444)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:802)
... 26 more
Caused by: java.sql.SQLSyntaxErrorException: ORA-02275: such a referential constraint already exists in the table
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:447)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:396)
at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:951)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:513)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:227)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:531)
at oracle.jdbc.driver.T4CStatement.doOall8(T4CStatement.java:195)
at oracle.jdbc.driver.T4CStatement.executeForRows(T4CStatement.java:1036)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1336)
at oracle.jdbc.driver.OracleStatement.executeUpdateInternal(OracleStatement.java:1845)
at oracle.jdbc.driver.OracleStatement.executeUpdate(OracleStatement.java:1810)
at oracle.jdbc.driver.OracleStatementWrapper.executeUpdate(OracleStatementWrapper.java:294)
at org.hibernate.tool.schema.internal.TargetDatabaseImpl.accept(TargetDatabaseImpl.java:56)
... 36 more
wrz 21, 2015 7:14:37 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in ServletContext resource [/WEB-INF/spring/root-context.xml]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: iBankPU] Unable to build Hibernate SessionFactory
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1553)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:973)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:750)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4939)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5434)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: iBankPU] Unable to build Hibernate SessionFactory
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.persistenceException(EntityManagerFactoryBuilderImpl.java:877)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:805)
at org.hibernate.jpa.HibernatePersistenceProvider.createContainerEntityManagerFactory(HibernatePersistenceProvider.java:135)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:336)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1612)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1549)
... 21 more
Caused by: org.hibernate.tool.schema.spi.SchemaManagementException: Unable to execute schema management to JDBC target [alter table transfers add constraint FK1vp11ydp2tn6fufhmfcr2is8x foreign key (fromAccId) references usersAccounts]
at org.hibernate.tool.schema.internal.TargetDatabaseImpl.accept(TargetDatabaseImpl.java:59)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.applySqlString(SchemaMigratorImpl.java:371)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.applySqlStrings(SchemaMigratorImpl.java:360)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.applyForeignKeys(SchemaMigratorImpl.java:325)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.doMigrationToTargets(SchemaMigratorImpl.java:157)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.doMigration(SchemaMigratorImpl.java:59)
at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:129)
at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:97)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:481)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:444)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:802)
... 26 more
Caused by: java.sql.SQLSyntaxErrorException: ORA-02275: such a referential constraint already exists in the table
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:447)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:396)
at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:951)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:513)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:227)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:531)
at oracle.jdbc.driver.T4CStatement.doOall8(T4CStatement.java:195)
at oracle.jdbc.driver.T4CStatement.executeForRows(T4CStatement.java:1036)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1336)
at oracle.jdbc.driver.OracleStatement.executeUpdateInternal(OracleStatement.java:1845)
at oracle.jdbc.driver.OracleStatement.executeUpdate(OracleStatement.java:1810)
at oracle.jdbc.driver.OracleStatementWrapper.executeUpdate(OracleStatementWrapper.java:294)
at org.hibernate.tool.schema.internal.TargetDatabaseImpl.accept(TargetDatabaseImpl.java:56)
... 36 more
wrz 21, 2015 7:14:37 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Error listenerStart
wrz 21, 2015 7:14:37 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Context [/ibank] startup failed due to previous errors
wrz 21, 2015 7:14:37 PM org.apache.catalina.core.ApplicationContext log
INFO: Closing Spring root WebApplicationContext
wrz 21, 2015 7:14:37 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
SEVERE: The web application [/ibank] registered the JDBC driver [oracle.jdbc.OracleDriver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
wrz 21, 2015 7:14:37 PM org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks
SEVERE: The web application [/ibank] created a ThreadLocal with key of type [org.apache.log4j.helpers.ThreadLocalMap] (value [org.apache.log4j.helpers.ThreadLocalMap@3de81e58]) and a value of type [java.util.Hashtable] (value [{}]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
wrz 21, 2015 7:14:37 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8181"]
wrz 21, 2015 7:14:37 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-bio-8009"]
wrz 21, 2015 7:14:37 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 13368 ms
我只更改我的 pom 文件:
<properties>
<java-version>1.8</java-version>
<spring.security.version>3.2.0.RELEASE</spring.security.version>
<org.springframework-version>4.0.2.RELEASE</org.springframework-version>
<org.aspectj-version>1.6.10</org.aspectj-version>
<org.slf4j-version>1.6.6</org.slf4j-version>
<hibernate.version>5.0.1.Final</hibernate.version>
</properties>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>${hibernate.version}</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>${hibernate.version}</version>
</dependency>
也许我的根上下文文件会有用:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd">
<!-- Root Context: defines shared resources visible to all other web components -->
<tx:annotation-driven transaction-manager="transactionManager" />
<jpa:repositories base-package="pl.piotr.ibank" />
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" />
<property name="url" value="jdbc:oracle:thin:@localhost:1521:XE" />
<property name="username" value="HR" />
<property name="password" value="asdfghj" />
</bean>
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="persistenceUnitName" value="iBankPU" />
<property name="packagesToScan" value="pl.piotr.ibank.model" />
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<bean id="myAuthenticationSuccessHandler" class="pl.piotr.ibank.security.MyAuthenticationSuccessHandler" />
</beans>
用户帐户类
@Entity
@Table(name = "usersAccounts")
public class UserAccount implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue
@Column(name = "id")
private Long id;
@NotNull
@Column(name = "accountNr")
private String accountNr;
@NotNull
@Column(name = "balance")
private float balance;
@NotNull
@Column(name = "createDate")
private LocalDateTime createDate;
@Column(name = "expiredDate")
private LocalDateTime expiredDate;
@Column(name = "lastOperation")
private LocalDateTime lastOperation;
@Column(name = "transfersCount")
private int transfersCount;
@OneToOne
@JoinColumn(name = "userId")
private User user;
@ManyToOne
@JoinColumn(name = "investmentId")
private InvestmentType investmentType;
@ManyToOne
@JoinColumn(name = "personalAccountId")
private PersonalAccountType personalAccountType;
@ManyToOne
@JoinColumn(name = "savingAccountId")
private SavingAccountType savingAccountType;
@OneToMany(mappedBy = "userAccountFrom", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private Set<Transfer> transferFromSet;
@OneToMany(mappedBy = "userAccountTo", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private Set<Transfer> transferToSet;
...
}
转类:
@Entity
@Table(name = "transfers")
public class Transfer implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue
@Column(name = "id")
private Long id;
@NotNull
@Column(name = "title")
private String title;
@NotNull
@Column(name = "transferDate")
private LocalDateTime transferDate;
@NotNull
@Column(name = "amount")
private float amount;
@ManyToOne
@JoinColumn(name = "fromAccId")
private UserAccount userAccountFrom;
@ManyToOne
@JoinColumn(name = "toAccId")
private UserAccount userAccountTo;
....
}
最佳答案
如所述here , 我还从 Hibernate 4 迁移到 Hibernate 5 以利用新的 Java LocalDateTime API，然后我开始遇到与您相同的问题:ORA-02275: such a referential constraint already exists in the table .
我通过添加属性解决了这个问题:<prop key="hibernate.id.new_generator_mappings">false</prop>如所述here .
然后我开始遇到另一个问题，比如 one ，其中 Hibernate 没有找到序列，在我的例子中，通过替换所有 GenerationType.AUTO 解决了这个问题GenerationType.SEQUENCE 的注释.
更新:后来，我所有的序列值都乘以 50，如 here ，所以我不得不添加这个 allocationSize = 1在我的域类中。
关于java - 从 Hibernate 4.3.6 迁移到 Hibernate 5，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32701093/
我真的很习惯使用Ruby编写以下代码:my_hash={}my_hash['test']=1Java中对应的数据结构是什么？ 最佳答案 HashMapmap=newHashMap();map.put("test",1);我假设？ 关于java-等价于Java中的RubyHash，我们在StackOverflow上找到一个类似的问题： https://stackoverflow.com/questions/22737685/
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这篇文章是继上一篇文章“Observability：从零开始创建Java微服务并监控它（一）”的续篇。在上一篇文章中，我们讲述了如何创建一个Javaweb应用，并使用Filebeat来收集应用所生成的日志。在今天的文章中，我来详述如何收集应用的指标，使用APM来监控应用并监督web服务的在线情况。源码可以在地址 https://github.com/liu-xiao-guo/java_observability 进行下载。摄入指标指标被视为可以随时更改的时间点值。当前请求的数量可以改变任何毫秒。你可能有1000个请求的峰值，然后一切都回到一个请求。这也意味着这些指标可能不准确，你还想提取最小/
HashMap中为什么引入红黑树，而不是AVL树呢1.概述开始学习这个知识点之前我们需要知道，在JDK1.8以及之前，针对HashMap有什么不同。JDK1.7的时候，HashMap的底层实现是数组+链表JDK1.8的时候，HashMap的底层实现是数组+链表+红黑树我们要思考一个问题，为什么要从链表转为红黑树呢。首先先让我们了解下链表有什么不好？？？2.链表上述的截图其实就是链表的结构，我们来看下链表的增删改查的时间复杂度增：因为链表不是线性结构，所以每次添加的时候，只需要移动一个节点，所以可以理解为复杂度是N(1)删：算法时间复杂度跟增保持一致查：既然是非线性结构，所以查询某一个节点的时候
遍历文件夹我们通常是使用递归进行操作，这种方式比较简单，也比较容易理解。本文为大家介绍另一种不使用递归的方式，由于没有使用递归，只用到了循环和集合，所以效率更高一些！一、使用递归遍历文件夹整体思路1、使用File封装初始目录，2、打印这个目录3、获取这个目录下所有的子文件和子目录的数组。4、遍历这个数组，取出每个File对象4-1、如果File是否是一个文件，打印4-2、否则就是一个目录，递归调用代码实现publicclassSearchFile{publicstaticvoidmain(String[]args){//初始目录Filedir=newFile("d:/Dev");Datebeg
我基本上来自Java背景并且努力理解Ruby中的模运算。(5%3)(-5%3)(5%-3)(-5%-3)Java中的上述操作产生，2个-22个-2但在Ruby中，相同的表达式会产生21个-1-2.Ruby在逻辑上有多擅长这个？模块操作在Ruby中是如何实现的？如果将同一个操作定义为一个web服务，两个服务如何匹配逻辑。 最佳答案 在Java中，模运算的结果与被除数的符号相同。在Ruby中，它与除数的符号相同。remainder()在Ruby中与被除数的符号相同。您可能还想引用modulooperation.
Java的Collections.unmodifiableList和Collections.unmodifiableMap在Ruby标准API中是否有等价物？ 最佳答案 使用freeze应用程序接口(interface):Preventsfurthermodificationstoobj.ARuntimeErrorwillberaisedifmodificationisattempted.Thereisnowaytounfreezeafrozenobject.SeealsoObject#frozen?.Thismethodretur
在Java中，可以像这样从一个字符串创建一个IO流:Readerr=newStringReader("mytext");我希望能够在Ruby中做同样的事情，这样我就可以获取一个字符串并将其视为一个IO流。 最佳答案 r=StringIO.new("mytext")和here'sthedocumentation. 关于java-Java的StringReader的Ruby等价物是什么？，我们在StackOverflow上找到一个类似的问题： https://st