使用 Spring Data JPA插入数据到数据表时，抛出如下错误信息：
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Column 'box_id' specified twice
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:425)
at com.mysql.jdbc.Util.getInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:944)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3978)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3914)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2530)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2683)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2495)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1903)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2124)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2058)
at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5158)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2043)
at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_executeUpdate(FilterChainImpl.java:2723)
at com.alibaba.druid.filter.FilterAdapter.preparedStatement_executeUpdate(FilterAdapter.java:1069)
at com.alibaba.druid.filter.FilterEventAdapter.preparedStatement_executeUpdate(FilterEventAdapter.java:491)
at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_executeUpdate(FilterChainImpl.java:2721)
at com.alibaba.druid.proxy.jdbc.PreparedStatementProxyImpl.executeUpdate(PreparedStatementProxyImpl.java:158)
at com.alibaba.druid.pool.DruidPooledPreparedStatement.executeUpdate(DruidPooledPreparedStatement.java:253)
at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94)
at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57)
... 123 common frames omitted
上面错误是因为我们在实体中，使用 @Column 注解重复的声明了某个列。例如：
@Entity
@Table(name = "t_users")
public class User {
@Id
@Column(name = "id", nullable = false, length = 10)
private Long id;
@Column(name = "name", length = 50)
private String name;
@Column(name = "name", length = 10)
private String sex;
}上面代码中，name 列被重复声明了。将最后一个 name 改为 sex，代码如下：
@Entity
@Table(name = "t_users")
public class User {
@Id
@Column(name = "id", nullable = false, length = 10)
private Long id;
@Column(name = "name", length = 50)
private String name;
@Column(name = "sex", length = 10)
private String sex;
}问题成功解决。
