java - JPA @MapsId 插入不正确的列名

Question

尽管遵循了网上的所有示例，但我还是无法让@MapsId 正常工作。

这是我的设置:

pom.xml:

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-entitymanager</artifactId>
    <version>4.3.5.Final</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.31</version>
</dependency>

DDL 脚本:

CREATE TABLE Subscription (
    id bigint not null primary key auto_increment,
    active boolean not null,
    maxNumUsers int not null
)ENGINE=InnoDB;

CREATE TABLE t.Project (
    name varchar(32) not null,
    subscriptionId bigint not null
)ENGINE=InnoDB;

ALTER TABLE t.Project ADD CONSTRAINT `projectPK` PRIMARY KEY (name, subscriptionId);
ALTER TABLE t.Project ADD CONSTRAINT `projectSubscriptionFK` FOREIGN KEY (subscriptionId) REFERENCES t.Subscription(id);

项目编号.java:

@Embeddable
public class ProjectId implements Serializable {
    private Long subscriptionId;
    private String name;

项目.java:

@Entity
@Table(schema = "t")
public class Project {
    @EmbeddedId
    private ProjectId id;

    @ManyToOne
    @MapsId("subscriptionId")
    //@JoinColumn(name = "subscriptionId", referencedColumnName = "id", insertable = false, updatable = false)
    private Subscription subscription;

订阅.java:

@Entity
@Table(schema = "t")
public class Subscription {

    @OneToMany(mappedBy = "subscription", cascade = CascadeType.ALL)
    private Map<ProjectId, Project> projects = new HashMap<>();

当我插入时，出现以下错误:

Hibernate: insert into t.Project (name, subscription_id) values (?, ?) 2014-07-20 11:06:59,193 org.hibernate.engine.jdbc.spi.SqlExceptionHelper - SQL Error: 1054, SQLState: 42S22 2014-07-20 11:06:59,193 org.hibernate.engine.jdbc.spi.SqlExceptionHelper - Unknown column 'subscription_id' in 'field list'

...

... 94 more Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'subscription_id' in 'field list' at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:526) at com.mysql.jdbc.Util.handleNewInstance(Util.java:408) at com.mysql.jdbc.Util.getInstance(Util.java:383) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1062) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4226) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4158) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2615) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2776) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2840) at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2082) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2334) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2262) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2246) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:187) ... 114 more

如果我在 Project.subscription 上取消注释 @JoinColumn 并重新部署，我会收到此错误:

... 21 more Caused by: org.hibernate.MappingException: Repeated column in mapping for collection: t.Subscription.projects column: subscriptionId

我也试过删除 @MapsId，我仍然收到重复列错误。

我不知道如何解决这个问题。如有任何建议，我们将不胜感激。

谢谢

---

更新:如果我将 Subscription.projects 设为列表而不是 map ，并将 JoinColumn 添加到 project.subscription，它就可以工作。但是，如果我将 subscription.projects 改回 map ，我将再次开始获取 org.hibernate.MappingException: Repeated 列。显然，我真的很想使用 map ，所以我会继续挖掘。

Answer 1

当使用 mapsId 注释时，您指定关系共享和控制由 Id 映射映射的字段，因此关系映射中的字段覆盖 Id 映射中的字段。这意味着 JPA 将使用 subscription_id 默认值，除非您指定您注释掉的连接列:

@JoinColumn(name = "subscriptionId", referencedColumnName = "id")