问题
Having some trouble getting this working. I am creating a site with a Tournament, which users can register for. The Tournament will have a list of registered members. It's not holding User objects, just the user email address, which is the a key for the user table anyway. I want to store the array list in such a way that I will have multiple copies of the tournament id, but only one instance of a username per tournament id.
eg T_ID Username 1 Tom 1 Mike 1 John 2 Tom 2 Chris 2 Timmy 3 Timmy 3 Chris
etc
Here's the SQL for the table.
DROP TABLE IF EXISTS `mtc`.`tournament` ;
CREATE TABLE IF NOT EXISTS `mtc`.`tournament` (
`id` INT NOT NULL,
`tournamentName` VARCHAR(100) NULL,
`tournamentGender` VARCHAR(45) NULL,
`tournamentType` VARCHAR(45) NULL,
`tournamentCategory` VARCHAR(45) NULL,
`tournamentStyle` VARCHAR(45) NULL,
PRIMARY KEY (`id`))
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `mtc`.`tournament_eligible`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `mtc`.`tournament_eligible` ;
CREATE TABLE IF NOT EXISTS `mtc`.`tournament_eligible` (
`id` INT NOT NULL,
`username` VARCHAR(45) NULL,
PRIMARY KEY (`id`),
CONSTRAINT `fk_tournament_eligible_tournament1`
FOREIGN KEY (`id`)
REFERENCES `mtc`.`tournament` (`id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB;
I have two classes as such.
Tournament.java
@Entity
@Table(name = "tournament")
public class Tournament implements Event {
@Id
@GeneratedValue
private int id;
@OneToMany
@JoinColumn(name = "id")
private List<User> eligible; // Contains a list of eligible members
@Size(min = 5, max = 45, message = "Tournament Name must be between 5 and 60 characters", groups = {
PersistenceValidationGroup.class, FormValidationGroup.class })
private String tournamentName; // Specified the name of the tournament
private String tournamentGender = "MIXED"; // Specifies where a tournament
// is M(ale), F(emale) or MIXED;
private String tournamentType = "S"; // Specifies S(ingles) or D(oubles)
private String tournamentCategory = "O"; // Specifies Member_Type to be
// S(enior) only, J(unior) only,
// or O(pen) Tournament
private String tournamentStyle = "L"; // Specfies type of Tournament to be
// (L)adder/(L)eague, (B)ucket or
// (G)roup - Probably change this to
// a class later on.
public Tournament() {
this.eligible = new ArrayList<User>();
}
// getters and setters
The Register Class
@Entity
@Table(name="tournament_eligible")
public class Registered {
@Id
@Column(name="id")
private int tournamentID;
@Column(name="username")
private String username;
@OneToMany(mappedBy="tournament")
private List<String> registered;
// getter and setters
I am using the proper javax.* annotations, not the Hibernate ones.
Current Error: Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on events.tournaments.Tournament.eligible references an unknown entity: java.util.List
I do have the Hibernate config set up to look in the package with the Register entity.
<beans profile="production">
<jee:jndi-lookup jndi-name="jdbc/mtc" id="dataSource"
expected-type="javax.sql.DataSource">
</jee:jndi-lookup>
<bean id="transactionManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"></property>
</bean>
<tx:annotation-driven />
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSource"></property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
</props>
</property>
<property name="packagesToScan">
<list>
<value>users</value>
<value>dao</value>
<value>events.tournaments</value>
</list>
</property>
</bean>
<bean id="exceptionTranslator"
class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor">
</bean>
</beans>
回答1:
In your Register class, you are trying to map a list of strings as if they were entities:
@OneToMany(mappedBy="tournament")
private List<String> registered;
@OneToMany is for relationships between entities only. Neither List nor String are entities. If you want to map a Collection of basic values (like String) to a table, take a look at the @CollectionTable annotation.
回答2:
@Entity
@Table(name="tournament")
public class Tournament implements Event {
@Id
@GeneratedValue
private int id;
@ElementCollection
@CollectionTable (name = "tournament_eligible", joinColumns=@JoinColumn(name="id"))
private List<String> username; // Contains a list of eligible members
@Size(min=5, max=45, message="Tournament Name must be between 5 and 60 characters",groups={PersistenceValidationGroup.class, FormValidationGroup.class})
private String tournamentName; // Specified the name of the tournament
private String tournamentGender = "MIXED"; // Specifies where a tournament is M(ale), F(emale) or MIXED;
private String tournamentType = "S"; // Specifies S(ingles) or D(oubles)
private String tournamentCategory = "O"; // Specifies Member_Type to be S(enior) only, J(unior) only, or O(pen) Tournament
private String tournamentStyle = "L"; // Specfies type of Tournament to be (L)adder/(L)eague, (B)ucket or (G)roup - Probably change this to a class later on.
public Tournament(){
this.username = new ArrayList<String>();
I got rid of the Registered class. It was a bit superfluous and not really necessary for String objects.
来源：https://stackoverflow.com/questions/21379955/hibernate-persisting-arraylist-issues