EclipseLink JPA 持久化时重复条目
EclipseLink JPA Duplicate entry when persisting
我在尝试保留带注释的对象时遇到这个奇怪的错误。
这是我的代码：
if (hashTags != null && !hashTags.isEmpty()) {
tweet.setHashTags(new LinkedList<HashTag>());
for (HashTag hashTag : hashTags) {
HashTag hashTagEntity = em
.find(HashTag.class, hashTag.getTag());
if (hashTagEntity == null) {
LogWrapper.logger.debug("H: " + hashTag.getTag());
em.persist(hashTag);
tweet.getHashTags().add(hashTag);
} else {
tweet.getHashTags().add(hashTagEntity);
}
}
}
我知道，如果您尝试保留一个现有对象，您会得到该异常，但我确实在调用 persist 方法之前检查了这一点。此外，我找不到导致异常的主键，既不在我的日志文件中，也不在我的 MySQL 数据库中，这让我感到困惑，我如何获得一个异常，指示我的数据库中不存在的主键值第一名.
编辑
这些是我的注释类，其中我只显示属性和注释：
@Entity
public class Tweet {
@Id
@Column(name = "ID")
private long id;
private Usuario usuario;
private String texto;
@Temporal(TemporalType.TIMESTAMP)
private Date fecha;
private int numRetweets;
@ManyToMany(fetch = FetchType.EAGER)
@JoinTable(name = "TWEET_USUARIO_MENCIONADO", joinColumns = { @JoinColumn(name = "TWEET_ID", referencedColumnName = "ID") }, inverseJoinColumns = { @JoinColumn(name = "USUARIO_ID", referencedColumnName = "ID") })
private LinkedList<Usuario> usuariosReferenciados;
@ManyToMany(fetch = FetchType.EAGER)
@JoinTable(name = "TWEET_HASHTAG", joinColumns = { @JoinColumn(name = "TWEET_ID", referencedColumnName = "ID") }, inverseJoinColumns = { @JoinColumn(name = "HASHTAG_ID", referencedColumnName = "ID") })
private LinkedList<HashTag> hashTags;
...
@Entity
@Access(AccessType.FIELD)
public class Usuario {
@Id
@Column(name = "ID")
private long id;
private String nombreEnPantalla;
private int numTweets;
@Temporal(TemporalType.TIMESTAMP)
private Date fechaRegistro;
@OneToMany(mappedBy = "usuario", fetch = FetchType.EAGER)
private LinkedList<Tweet> tweets;
private int numFollowers;
private double tweetsPerDay;
...
@Entity
public class HashTag {
@Id
@Column(name = "ID")
private String tag;
...
这是我遇到问题的整个方法代码：
public Tweet crearTweet(long idTweet, Date fechaTweet, int numRetweets,
String textoTweet, long idUsuario, Date fechaRegistroUsuario,
int followersUsuario, String nombreEnPantallaUsuario,
int numTweetsUsuario, List<Usuario> usuariosMencionados,
List<HashTag> hashTags) {
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
Tweet tweet = new Tweet();
tweet.setFecha(fechaTweet);
tweet.setId(idTweet);
tweet.setNumRetweets(numRetweets);
tweet.setTexto(textoTweet);
em.persist(tweet);
Usuario user = em.find(Usuario.class, idUsuario);
if (user == null) {
user = new Usuario();
user.setFechaRegistro(fechaRegistroUsuario);
user.setId(idUsuario);
user.setNombreEnPantalla(nombreEnPantallaUsuario);
user.setNumFollowers(followersUsuario);
user.setNumTweets(numTweetsUsuario);
em.persist(user);
}
tweet.setUsuario(user);
if (usuariosMencionados != null && !usuariosMencionados.isEmpty()) {
tweet.setUsuariosReferenciados(new LinkedList<Usuario>());
for (Usuario usuarioMencionado : usuariosMencionados) {
Usuario usuarioEntity = em.find(Usuario.class,
usuarioMencionado.getId());
if (usuarioEntity == null) {
LogWrapper.logger.debug("U: " + usuarioMencionado.getId()
+ " " + usuarioMencionado.getNombreEnPantalla());
em.persist(usuarioMencionado);
tweet.getUsuariosReferenciados().add(usuarioMencionado);
} else {
tweet.getUsuariosReferenciados().add(usuarioEntity);
}
}
}
if (hashTags != null && !hashTags.isEmpty()) {
tweet.setHashTags(new LinkedList<HashTag>());
for (HashTag hashTag : hashTags) {
HashTag hashTagEntity = em
.find(HashTag.class, hashTag.getTag());
if (hashTagEntity == null) {
LogWrapper.logger.debug("H: " + hashTag.getTag());
em.persist(hashTag);
tweet.getHashTags().add(hashTag);
} else {
tweet.getHashTags().add(hashTagEntity);
}
}
}
em.getTransaction().commit();
em.close();
return tweet;
}
这是整个堆栈跟踪：
[EL Warning]: 2015-03-17 01:50:48.411--UnitOfWork(841203)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '??' for key 'PRIMARY'
Error Code: 1062
Call: INSERT INTO HASHTAG (ID) VALUES (?)
bind => [1 parameter bound]
Query: InsertObjectQuery(um.es.TFG.modelo.HashTag@7a77e4)
Exception in thread "main" javax.persistence.RollbackException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '??' for key 'PRIMARY'
Error Code: 1062
Call: INSERT INTO HASHTAG (ID) VALUES (?)
bind => [1 parameter bound]
Query: InsertObjectQuery(um.es.TFG.modelo.HashTag@7a77e4)
at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:159)
at um.es.TFG.dao.jpa.JPATweetDAO.crearTweet(JPATweetDAO.java:76)
at um.es.TFG.core.TweetProcessorMiner.startProcess(TweetProcessorMiner.java:105)
at um.es.TFG.main.Main.main(Main.java:24)
Caused by: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '??' for key 'PRIMARY'
Error Code: 1062
Call: INSERT INTO HASHTAG (ID) VALUES (?)
bind => [1 parameter bound]
Query: InsertObjectQuery(um.es.TFG.modelo.HashTag@7a77e4)
at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:331)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:902)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeNoSelect(DatabaseAccessor.java:964)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.basicExecuteCall(DatabaseAccessor.java:633)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall(DatabaseAccessor.java:560)
at org.eclipse.persistence.internal.sessions.AbstractSession.basicExecuteCall(AbstractSession.java:2055)
at org.eclipse.persistence.sessions.server.ClientSession.executeCall(ClientSession.java:306)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:242)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:228)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.insertObject(DatasourceCallQueryMechanism.java:377)
at org.eclipse.persistence.internal.queries.StatementQueryMechanism.insertObject(StatementQueryMechanism.java:165)
at org.eclipse.persistence.internal.queries.StatementQueryMechanism.insertObject(StatementQueryMechanism.java:180)
at org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.insertObjectForWrite(DatabaseQueryMechanism.java:489)
at org.eclipse.persistence.queries.InsertObjectQuery.executeCommit(InsertObjectQuery.java:80)
at org.eclipse.persistence.queries.InsertObjectQuery.executeCommitWithChangeSet(InsertObjectQuery.java:90)
at org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.executeWriteWithChangeSet(DatabaseQueryMechanism.java:301)
at org.eclipse.persistence.queries.WriteObjectQuery.executeDatabaseQuery(WriteObjectQuery.java:58)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:904)
at org.eclipse.persistence.queries.DatabaseQuery.executeInUnitOfWork(DatabaseQuery.java:803)
at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWorkObjectLevelModifyQuery(ObjectLevelModifyQuery.java:108)
at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWork(ObjectLevelModifyQuery.java:85)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2896)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1857)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1839)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1790)
at org.eclipse.persistence.internal.sessions.CommitManager.commitNewObjectsForClassWithChangeSet(CommitManager.java:227)
at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsForClassWithChangeSet(CommitManager.java:194)
at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsWithChangeSet(CommitManager.java:139)
at org.eclipse.persistence.internal.sessions.AbstractSession.writeAllObjectsWithChangeSet(AbstractSession.java:4260)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase(UnitOfWorkImpl.java:1441)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1531)
at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitRootUnitOfWork(RepeatableWriteUnitOfWork.java:278)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitAndResume(UnitOfWorkImpl.java:1169)
at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:134)
... 3 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '??' for key 'PRIMARY'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
at com.mysql.jdbc.Util.getInstance(Util.java:360)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:971)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3887)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3823)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2435)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2582)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2530)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1907)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2141)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2077)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2062)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:892)
... 35 more
编辑 2
如果我在每次坚持操作后执行 em.flush() 并在我的代码中注释以下行，错误将停止弹出：
tweet.getUsuariosReferenciados().add(usuarioMencionado);
tweet.getUsuariosReferenciados().add(usuarioEntity);
tweet.getHashTags().add(hashTag);
tweet.getHashTags().add(hashTagEntity);
我正在评论以上几行，试图尽可能少地执行操作来定位问题，我已经尝试过不评论这些行，但如果我这样做，我仍然会收到错误消息，但正如我所说，让他们评论并每次坚持后刷新，我的代码 运行 很好，它只是不将实体的另外两个列表（HashTags 和提到的用户）与我的主要实体（Tweet）相关联。
所以我现在知道，由于我在一个事务中做的很多事情都没有刷新，所以我收到了错误，但我不知道为什么它说重复键。
深入查看EclipseLink 生成的日志后，我发现我的主要问题是由于不兼容的字符编码。我的源正在生成以 UTF-8 编码的文本，而我的数据库使用的是 latin1 编码。因此，在我的一个表中插入一个主键无法在 latin1 中正确表示的新行后，它被插入为 ???每个询问符号替换一个字符并且键的长度与原始单词的长度匹配，这就是为什么我得到重复输入异常的原因，因为在插入例如一些由 3 个奇怪字符组成的奇怪单词之后？？？当我试图插入另一个由 3 个不同的奇怪字符组成的不同的奇怪单词时，我会得到重复条目异常。我尝试将我的数据库中的表配置为使用 UTF-8，但我仍然遇到问题，因为 MySQL 中的 utf8 仅使用 3 个字节来表示一个字符，而我的源具有以 4 个字节编码的 UTF-8。所以我为我的表使用了 utf8mb4，但这不足以解决问题，我需要用 character_set_server=utf8mb4 配置 MySQL 服务器，重新启动服务器，这样 Connector/J 就可以了正确地自动检测 UTF-8 设置。
我在尝试保留带注释的对象时遇到这个奇怪的错误。
这是我的代码：
if (hashTags != null && !hashTags.isEmpty()) {
tweet.setHashTags(new LinkedList<HashTag>());
for (HashTag hashTag : hashTags) {
HashTag hashTagEntity = em
.find(HashTag.class, hashTag.getTag());
if (hashTagEntity == null) {
LogWrapper.logger.debug("H: " + hashTag.getTag());
em.persist(hashTag);
tweet.getHashTags().add(hashTag);
} else {
tweet.getHashTags().add(hashTagEntity);
}
}
}
我知道，如果您尝试保留一个现有对象，您会得到该异常，但我确实在调用 persist 方法之前检查了这一点。此外，我找不到导致异常的主键，既不在我的日志文件中，也不在我的 MySQL 数据库中，这让我感到困惑，我如何获得一个异常，指示我的数据库中不存在的主键值第一名.
编辑
这些是我的注释类，其中我只显示属性和注释：
@Entity
public class Tweet {
@Id
@Column(name = "ID")
private long id;
private Usuario usuario;
private String texto;
@Temporal(TemporalType.TIMESTAMP)
private Date fecha;
private int numRetweets;
@ManyToMany(fetch = FetchType.EAGER)
@JoinTable(name = "TWEET_USUARIO_MENCIONADO", joinColumns = { @JoinColumn(name = "TWEET_ID", referencedColumnName = "ID") }, inverseJoinColumns = { @JoinColumn(name = "USUARIO_ID", referencedColumnName = "ID") })
private LinkedList<Usuario> usuariosReferenciados;
@ManyToMany(fetch = FetchType.EAGER)
@JoinTable(name = "TWEET_HASHTAG", joinColumns = { @JoinColumn(name = "TWEET_ID", referencedColumnName = "ID") }, inverseJoinColumns = { @JoinColumn(name = "HASHTAG_ID", referencedColumnName = "ID") })
private LinkedList<HashTag> hashTags;
...
@Entity
@Access(AccessType.FIELD)
public class Usuario {
@Id
@Column(name = "ID")
private long id;
private String nombreEnPantalla;
private int numTweets;
@Temporal(TemporalType.TIMESTAMP)
private Date fechaRegistro;
@OneToMany(mappedBy = "usuario", fetch = FetchType.EAGER)
private LinkedList<Tweet> tweets;
private int numFollowers;
private double tweetsPerDay;
...
@Entity
public class HashTag {
@Id
@Column(name = "ID")
private String tag;
...
这是我遇到问题的整个方法代码：
public Tweet crearTweet(long idTweet, Date fechaTweet, int numRetweets,
String textoTweet, long idUsuario, Date fechaRegistroUsuario,
int followersUsuario, String nombreEnPantallaUsuario,
int numTweetsUsuario, List<Usuario> usuariosMencionados,
List<HashTag> hashTags) {
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
Tweet tweet = new Tweet();
tweet.setFecha(fechaTweet);
tweet.setId(idTweet);
tweet.setNumRetweets(numRetweets);
tweet.setTexto(textoTweet);
em.persist(tweet);
Usuario user = em.find(Usuario.class, idUsuario);
if (user == null) {
user = new Usuario();
user.setFechaRegistro(fechaRegistroUsuario);
user.setId(idUsuario);
user.setNombreEnPantalla(nombreEnPantallaUsuario);
user.setNumFollowers(followersUsuario);
user.setNumTweets(numTweetsUsuario);
em.persist(user);
}
tweet.setUsuario(user);
if (usuariosMencionados != null && !usuariosMencionados.isEmpty()) {
tweet.setUsuariosReferenciados(new LinkedList<Usuario>());
for (Usuario usuarioMencionado : usuariosMencionados) {
Usuario usuarioEntity = em.find(Usuario.class,
usuarioMencionado.getId());
if (usuarioEntity == null) {
LogWrapper.logger.debug("U: " + usuarioMencionado.getId()
+ " " + usuarioMencionado.getNombreEnPantalla());
em.persist(usuarioMencionado);
tweet.getUsuariosReferenciados().add(usuarioMencionado);
} else {
tweet.getUsuariosReferenciados().add(usuarioEntity);
}
}
}
if (hashTags != null && !hashTags.isEmpty()) {
tweet.setHashTags(new LinkedList<HashTag>());
for (HashTag hashTag : hashTags) {
HashTag hashTagEntity = em
.find(HashTag.class, hashTag.getTag());
if (hashTagEntity == null) {
LogWrapper.logger.debug("H: " + hashTag.getTag());
em.persist(hashTag);
tweet.getHashTags().add(hashTag);
} else {
tweet.getHashTags().add(hashTagEntity);
}
}
}
em.getTransaction().commit();
em.close();
return tweet;
}
这是整个堆栈跟踪：
[EL Warning]: 2015-03-17 01:50:48.411--UnitOfWork(841203)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '??' for key 'PRIMARY'
Error Code: 1062
Call: INSERT INTO HASHTAG (ID) VALUES (?)
bind => [1 parameter bound]
Query: InsertObjectQuery(um.es.TFG.modelo.HashTag@7a77e4)
Exception in thread "main" javax.persistence.RollbackException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '??' for key 'PRIMARY'
Error Code: 1062
Call: INSERT INTO HASHTAG (ID) VALUES (?)
bind => [1 parameter bound]
Query: InsertObjectQuery(um.es.TFG.modelo.HashTag@7a77e4)
at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:159)
at um.es.TFG.dao.jpa.JPATweetDAO.crearTweet(JPATweetDAO.java:76)
at um.es.TFG.core.TweetProcessorMiner.startProcess(TweetProcessorMiner.java:105)
at um.es.TFG.main.Main.main(Main.java:24)
Caused by: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '??' for key 'PRIMARY'
Error Code: 1062
Call: INSERT INTO HASHTAG (ID) VALUES (?)
bind => [1 parameter bound]
Query: InsertObjectQuery(um.es.TFG.modelo.HashTag@7a77e4)
at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:331)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:902)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeNoSelect(DatabaseAccessor.java:964)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.basicExecuteCall(DatabaseAccessor.java:633)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall(DatabaseAccessor.java:560)
at org.eclipse.persistence.internal.sessions.AbstractSession.basicExecuteCall(AbstractSession.java:2055)
at org.eclipse.persistence.sessions.server.ClientSession.executeCall(ClientSession.java:306)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:242)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:228)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.insertObject(DatasourceCallQueryMechanism.java:377)
at org.eclipse.persistence.internal.queries.StatementQueryMechanism.insertObject(StatementQueryMechanism.java:165)
at org.eclipse.persistence.internal.queries.StatementQueryMechanism.insertObject(StatementQueryMechanism.java:180)
at org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.insertObjectForWrite(DatabaseQueryMechanism.java:489)
at org.eclipse.persistence.queries.InsertObjectQuery.executeCommit(InsertObjectQuery.java:80)
at org.eclipse.persistence.queries.InsertObjectQuery.executeCommitWithChangeSet(InsertObjectQuery.java:90)
at org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.executeWriteWithChangeSet(DatabaseQueryMechanism.java:301)
at org.eclipse.persistence.queries.WriteObjectQuery.executeDatabaseQuery(WriteObjectQuery.java:58)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:904)
at org.eclipse.persistence.queries.DatabaseQuery.executeInUnitOfWork(DatabaseQuery.java:803)
at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWorkObjectLevelModifyQuery(ObjectLevelModifyQuery.java:108)
at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWork(ObjectLevelModifyQuery.java:85)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2896)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1857)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1839)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1790)
at org.eclipse.persistence.internal.sessions.CommitManager.commitNewObjectsForClassWithChangeSet(CommitManager.java:227)
at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsForClassWithChangeSet(CommitManager.java:194)
at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsWithChangeSet(CommitManager.java:139)
at org.eclipse.persistence.internal.sessions.AbstractSession.writeAllObjectsWithChangeSet(AbstractSession.java:4260)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase(UnitOfWorkImpl.java:1441)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1531)
at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitRootUnitOfWork(RepeatableWriteUnitOfWork.java:278)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitAndResume(UnitOfWorkImpl.java:1169)
at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:134)
... 3 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '??' for key 'PRIMARY'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
at com.mysql.jdbc.Util.getInstance(Util.java:360)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:971)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3887)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3823)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2435)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2582)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2530)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1907)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2141)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2077)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2062)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:892)
... 35 more
编辑 2
如果我在每次坚持操作后执行 em.flush() 并在我的代码中注释以下行，错误将停止弹出：
tweet.getUsuariosReferenciados().add(usuarioMencionado);
tweet.getUsuariosReferenciados().add(usuarioEntity);
tweet.getHashTags().add(hashTag);
tweet.getHashTags().add(hashTagEntity);
我正在评论以上几行，试图尽可能少地执行操作来定位问题，我已经尝试过不评论这些行，但如果我这样做，我仍然会收到错误消息，但正如我所说，让他们评论并每次坚持后刷新，我的代码 运行 很好，它只是不将实体的另外两个列表（HashTags 和提到的用户）与我的主要实体（Tweet）相关联。 所以我现在知道，由于我在一个事务中做的很多事情都没有刷新，所以我收到了错误，但我不知道为什么它说重复键。
深入查看EclipseLink 生成的日志后，我发现我的主要问题是由于不兼容的字符编码。我的源正在生成以 UTF-8 编码的文本，而我的数据库使用的是 latin1 编码。因此，在我的一个表中插入一个主键无法在 latin1 中正确表示的新行后，它被插入为 ???每个询问符号替换一个字符并且键的长度与原始单词的长度匹配，这就是为什么我得到重复输入异常的原因，因为在插入例如一些由 3 个奇怪字符组成的奇怪单词之后？？？当我试图插入另一个由 3 个不同的奇怪字符组成的不同的奇怪单词时，我会得到重复条目异常。我尝试将我的数据库中的表配置为使用 UTF-8，但我仍然遇到问题，因为 MySQL 中的 utf8 仅使用 3 个字节来表示一个字符，而我的源具有以 4 个字节编码的 UTF-8。所以我为我的表使用了 utf8mb4，但这不足以解决问题，我需要用 character_set_server=utf8mb4 配置 MySQL 服务器，重新启动服务器，这样 Connector/J 就可以了正确地自动检测 UTF-8 设置。