Question

我是Java编程的新手。我的课程中有一个枚举数据类型：

public class Persons {
    private String name;
    private String family;
    private Date birthDate;
    public enum degree {Bsd, Msd, prof};
    private degree degree;
    ...
}

在我的MySQL数据库中，我有一个学位为ENUM('Bsd','Mds','prof')的字段，我的hibernate映射是这样的：

<class name="Entity.Professor" table="tbl_professor">
     <id column="ProfessorId" name="ProfessorId"/>
     <property column="name" name="name"/>
     <property column="family" name="family"/>
     <property column="birthDate" name="birthDate"/>
     <property column="degree" name="degree"/>
</class>

当我想在我的表中插入新记录时，我收到此错误：

Hibernate: insert into tbl_professor (name, family, birthDate, degree, ProfessorId) values (?, ?, ?, ?, ?)
Apr 26, 2013 6:15:24 PM org.hibernate.util.JDBCExceptionReporter logExceptions
WARNING: SQL Error: 1265, SQLState: 01000
Apr 26, 2013 6:15:24 PM org.hibernate.util.JDBCExceptionReporter logExceptions
SEVERE: Data truncated for column 'degree' at row 1
Apr 26, 2013 6:15:24 PM org.hibernate.event.def.AbstractFlushingEventListener performExecutions
SEVERE: Could not synchronize database state with session
org.hibernate.exception.GenericJDBCException: Could not execute JDBC batch update
    at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:253)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:237)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:141)
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
    at DAO.ProfessorDAO.createProfessor(ProfessorDAO.java:21)
    at Entity.Test.main(Test.java:39)
Caused by: java.sql.BatchUpdateException: Data truncated for column 'degree' at row 1
    at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:2028)
    at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1451)
    at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:48)
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:246)
    ... 9 more
Caused by: java.sql.SQLException: Data truncated for column 'degree' at row 1
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3609)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3541)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2002)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2163)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2624)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2127)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2427)
    at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:1980)
    ... 12 more

Exception in thread "main" org.hibernate.exception.GenericJDBCException: Could not execute JDBC batch update
    at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:253)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:237)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:141)

任何人都可以帮助我吗？我真的很困惑enum数据类型。

Answer 1

数据截断是指您添加的记录长度超过数据库列的最大列大小（在您的情况下为degree）。

由于您的MySQL ENUM for DEGREE列有3种类型，您可以使用@Enumerated注释枚举，如下所示：

@Enumerated(EnumType.STRING)
private degree degree;

有关EnumType的更多信息。

Answer 2

你需要在hibernate中以不同方式映射枚举，Hibernate提供org.hibernate.type.EnumType来映射枚举类型

   <property name="degree">
      <type name="org.hibernate.type.EnumType">
         <param name="enumClass">pkg.degree</param>
      </type>
   </property>

如果要存储字符串而不是索引1,2等，则需要使用 12

12 - java.sql.Types.VARCHAR

查看链接 Hibernate map enum to varchar

Answer 3

您收到数据截断错误，因此我会检查您的MySQL列的允许长度。通常，如果该字段中的数据大于Hibernate / JPA映射或允许的db列的长度，则会看到此错误。

Answer 4

一种解决方案是不使用enum类型的mysql。另一种选择是普通字符串，或者更好的是一个额外的表，其中id为关系。

它有几个缺点。主要是维持它。您无法轻松更改订单或删除其中的内容

如果你谷歌搜索mysql这个页面是第3个，原因是：http://komlenic.com/244/8-reasons-why-mysqls-enum-data-type-is-evil/

java.sql.SQLException：为列截断的数据

4 个答案: