我想在三个实体之间建立多对一关系，即用户到棋盘(许多)和棋盘到卡片(许多)，即用户可以有很多棋盘，棋盘可以有很多卡片。我正在使用 Spring JPA 并自动创建数据库模式。我已经正确设置了属性，但无法正确连接它们以便自动构建数据库模式。这是我的模型类，请帮助:-
@Entity
@Table(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "userid")
private Long id;
@Column(name = "username")
private String username;
@Column(name = "password")
private String password;
@OneToMany(fetch = FetchType.LAZY ,mappedBy = "username" , targetEntity = Board.class)
private List<Board> boards;
}
板类
@Entity
@Table(name = "board")
public class Board {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "boardid")
private Long id;
@Column(name = "boardname")
private String boardname;
@Column(name = "boardcreationdate")
private DateTime boardCreationDate;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "userid", referencedColumnName = "userid")
private User username;
@OneToMany(fetch = FetchType.LAZY ,mappedBy = "boardname" , targetEntity = Board.class)
private Set<Card> cards;
}
卡片类
@Entity
@Table(name = "card")
public class Card {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "cardid")
private Long id;
@Column(name = "cardName")
private String cardName;
@Column(name = "cardcreationdate")
private DateTime cardCreationDate;
@Column(name = "cardtimeondone")
private DateTime cardTimeOnDone;
@Column(name = "cardlife")
private DateTime cardLife;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "boardid", referencedColumnName = "boardid")
private Board boardname;
}
这是带有一些属性的 application.properties 文件。
spring.datasource.initialize=true
spring.datasource.platform=mysql
spring.datasource.time-between-eviction-runs-millis=34000
spring.datasource.min-evictable-idle-time-millis=55000
spring.datasource.max-wait=28800000
spring.jpa.generate-ddl=true
spring.jpa.hibernate.ddl-auto=create
spring.jpa.properties.hibernate.dialect =org.hibernate.dialect.MySQL5Dialect
spring.jpa.properties.hibernate.format_sql=true
它正在创建模式但给出如下错误:-
2016-06-20 15:12:37.288 DEBUG 8772 --- [ main] org.hibernate.SQL :
alter table board
drop
foreign key FKbon6omt9qov9iduumkuj117xw
2016-06-20 15:12:37.357 DEBUG 8772 --- [ main] org.hibernate.SQL :
alter table board
drop
foreign key FKcefyg893q4c26nvw7uus84ts3
2016-06-20 15:12:37.386 WARN 8772 --- [ main] o.h.t.s.i.ExceptionHandlerLoggedImpl : GenerationTarget encountered exception accepting command : Unable to execute command [
alter table board
drop
foreign key FKcefyg893q4c26nvw7uus84ts3]
org.hibernate.tool.schema.spi.CommandAcceptanceException: Unable to execute command [
alter table board
drop
foreign key FKcefyg893q4c26nvw7uus84ts3]
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:63) ~[hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlString(SchemaDropperImpl.java:370) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlStrings(SchemaDropperImpl.java:355) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaDropperImpl.applyConstraintDropping(SchemaDropperImpl.java:327) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaDropperImpl.dropFromMetadata(SchemaDropperImpl.java:229) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaDropperImpl.performDrop(SchemaDropperImpl.java:153) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:125) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:111) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:137) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:64) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:458) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:465) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:881) [hibernate-entitymanager-5.1.0.Final.jar:5.1.0.Final]
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60) [spring-orm-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:338) [spring-orm-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:373) [spring-orm-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:362) [spring-orm-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1076) [spring-context-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:851) [spring-context-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) [spring-context-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:765) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:314) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1182) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1171) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at com.causecode.challenge.TrellocardlifeApplication.main(TrellocardlifeApplication.java:14) [classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_25]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_25]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_25]
at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0_25]
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144) [idea_rt.jar:na]
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Can't DROP 'FKcefyg893q4c26nvw7uus84ts3'; check that column/key exists
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_25]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_25]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_25]
at java.lang.reflect.Constructor.newInstance(Constructor.java:408) ~[na:1.8.0_25]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.Util.getInstance(Util.java:381) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1030) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2536) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2465) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:734) ~[mysql-connector-java-5.1.6.jar:na]
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:51) ~[hibernate-core-5.1.0.Final.jar:5.1.0.Final]
... 38 common frames omitted
2016-06-20 15:12:37.392 DEBUG 8772 --- [ main] org.hibernate.SQL :
alter table card
drop
foreign key FKgicrq63fj0nx3bh6wlncf235i
2016-06-20 15:12:37.424 DEBUG 8772 --- [ main] org.hibernate.SQL :
drop table if exists board
2016-06-20 15:12:37.437 DEBUG 8772 --- [ main] org.hibernate.SQL :
drop table if exists card
2016-06-20 15:12:37.448 DEBUG 8772 --- [ main] org.hibernate.SQL :
drop table if exists user
2016-06-20 15:12:37.468 DEBUG 8772 --- [ main] org.hibernate.SQL :
create table board (
boardid bigint not null auto_increment,
boardcreationdate tinyblob,
boardname varchar(255),
userid bigint,
primary key (boardid)
)
2016-06-20 15:12:37.539 DEBUG 8772 --- [ main] org.hibernate.SQL :
create table card (
id bigint not null auto_increment,
cardcreationdate tinyblob,
cardlife tinyblob,
card_name varchar(255),
cardtimeondone tinyblob,
boardid bigint,
primary key (id)
)
2016-06-20 15:12:37.600 DEBUG 8772 --- [ main] org.hibernate.SQL :
create table user (
userid bigint not null auto_increment,
password varchar(255),
username varchar(255),
primary key (userid)
)
2016-06-20 15:12:37.631 DEBUG 8772 --- [ main] org.hibernate.SQL :
alter table board
add constraint FKbon6omt9qov9iduumkuj117xw
foreign key (userid)
references user (userid)
2016-06-20 15:12:37.752 DEBUG 8772 --- [ main] org.hibernate.SQL :
alter table board
add constraint FKcefyg893q4c26nvw7uus84ts3
foreign key (boardname)
references board (boardid)
2016-06-20 15:12:37.812 WARN 8772 --- [ main] o.h.t.s.i.ExceptionHandlerLoggedImpl : GenerationTarget encountered exception accepting command : Unable to execute command [
alter table board
add constraint FKcefyg893q4c26nvw7uus84ts3
foreign key (boardname)
references board (boardid)]
org.hibernate.tool.schema.spi.CommandAcceptanceException: Unable to execute command [
alter table board
add constraint FKcefyg893q4c26nvw7uus84ts3
foreign key (boardname)
references board (boardid)]
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:63) ~[hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlString(SchemaCreatorImpl.java:423) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlStrings(SchemaCreatorImpl.java:408) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.createFromMetadata(SchemaCreatorImpl.java:359) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.performCreation(SchemaCreatorImpl.java:165) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:134) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:120) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:148) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:64) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:458) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:465) [hibernate-core-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:881) [hibernate-entitymanager-5.1.0.Final.jar:5.1.0.Final]
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60) [spring-orm-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:338) [spring-orm-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:373) [spring-orm-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:362) [spring-orm-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) [spring-beans-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1076) [spring-context-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:851) [spring-context-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) [spring-context-4.3.0.RC2.jar:4.3.0.RC2]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:765) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:314) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1182) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1171) [spring-boot-1.4.0.M3.jar:1.4.0.M3]
at com.causecode.challenge.TrellocardlifeApplication.main(TrellocardlifeApplication.java:14) [classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_25]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_25]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_25]
at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0_25]
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144) [idea_rt.jar:na]
Caused by: java.sql.SQLException: Cannot add foreign key constraint
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2536) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2465) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:734) ~[mysql-connector-java-5.1.6.jar:na]
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:51) ~[hibernate-core-5.1.0.Final.jar:5.1.0.Final]
... 37 common frames omitted
2016-06-20 15:12:37.814 DEBUG 8772 --- [ main] org.hibernate.SQL :
alter table card
add constraint FKgicrq63fj0nx3bh6wlncf235i
foreign key (boardid)
references board (boardid)
2016-06-20 15:12:37.900 INFO 8772 --- [ main] o.h.t.schema.internal.SchemaCreatorImpl : HHH000476: Executing import script 'org.hibernate.tool.schema.internal.exec.ScriptSourceInputNonExistentImpl@329bad59'
2016-06-20 15:12:37.954 INFO 8772 --- [ main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2016-06-20 15:12:39.191 INFO 8772 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2016-06-20 15:12:39.200 INFO 8772 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Starting beans in phase 0
2016-06-20 15:12:39.305 INFO 8772 --- [ main] c.c.challenge.TrellocardlifeApplication : Started TrellocardlifeApplication in 8.172 seconds (JVM running for 8.914)
2016-06-20 15:12:39.306 INFO 8772 --- [ Thread-3] s.c.a.AnnotationConfigApplicationContext : Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@7fad8c79: startup date [Mon Jun 20 15:12:31 IST 2016]; root of context hierarchy
2016-06-20 15:12:39.308 INFO 8772 --- [ Thread-3] o.s.c.support.DefaultLifecycleProcessor : Stopping beans in phase 0
2016-06-20 15:12:39.310 INFO 8772 --- [ Thread-3] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
2016-06-20 15:12:39.310 INFO 8772 --- [ Thread-3] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
Process finished with exit code 0
我觉得只有实体类有问题。请帮我定义一个正确的模型并在 mysql 中自动创建它们。
最佳答案
试试这样改:
@Entity
@Table(name = "user")
public class User {
@OneToMany(mappedBy = "user")
private List<Board> boards;
}
@Entity
@Table(name = "board")
public class Board {
@ManyToOne(cascade=CascadeType.PERSIST)
@JoinColumn(name = "userid")
private User user;
@OneToMany(mappedBy = "board")
private Set<Card> cards;
}
@Entity
@Table(name = "card")
public class Card {
@ManyToOne(cascade=CascadeType.PERSIST)
@JoinColumn(name = "boardid")
private Board board;
}
关于java - JPA中三个实体之间的一对多映射，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/37919019/