为什么不能将JPA / hibernate映射到MySQL blob类型？ [英] Why cant JPA/hibernate map to MySQL blob type?

问题描述

我得到以下错误：

 引起：org.hibernate.HibernateException：列PAYLOAD中TestTable的列类型错误。 Found：blob，expected：tinyblob 
 at org.hibernate.mapping.Table.validateColumns（Table.java:284）
 at org.hibernate.cfg.Configuration.validateSchema（Configuration.java:1174）
 at org.hibernate.tool.hbm2ddl.SchemaValidator.validate（SchemaValidator.java:139）
 at org.hibernate.impl.SessionFactoryImpl。< init>（SessionFactoryImpl.java:387）
在org.hibernate.cfg.Configuration.buildSessionFactory（Configuration.java:1385）
在org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory（AnnotationConfiguration.java:954）
在org.hibernate.ejb.Ejb3Configuration .buildEntityManagerFactory（Ejb3Configuration.java:883）
 ... 60 more 
  

列休眠正在抱怨声明为

  private byte [] messagePayload; 
 
 @Column（name =PAYLOAD）
 public byte [] getMessagePayload（）{
 return messagePayload; 
} 
 
 public void setMessagePayload（byte [] messagePayload）{
 this.messagePayload = messagePayload; 
 
 $ / code> 

MySQL表中的表被声明为BLOB类型。为什么Hibernate不想映射它，为什么它坚持使用TINYBLOB？

谢谢

解决方案

您可以尝试显式设置blob类型使用 columnDefinition 属性。像这样：

  @Column（name =PAYLOAD，columnDefinition =blob）
  
 
或使用@Lob注解：
 
 
  @Column（name =PAYLOAD）
 @Lob（type = LobType.BLOB）
  
 
I got the following error 
Caused by: org.hibernate.HibernateException: Wrong column type in TestTable for column PAYLOAD. Found: blob, expected: tinyblob
    at org.hibernate.mapping.Table.validateColumns(Table.java:284)
    at org.hibernate.cfg.Configuration.validateSchema(Configuration.java:1174)
    at org.hibernate.tool.hbm2ddl.SchemaValidator.validate(SchemaValidator.java:139)
    at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:387)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1385)
    at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:954)
    at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:883)
    ... 60 more
The column hibernate is complaining about is declared as 
private byte[]  messagePayload;

@Column(name="PAYLOAD")
public byte[] getMessagePayload() {
        return messagePayload;
}

public void setMessagePayload(byte[] messagePayload) {
 this.messagePayload = messagePayload;
}
The table in the MySQL table is declared as a BLOB type. Why doesnt Hibernate want to map to it and why does it insist that i use TINYBLOB? 

Thanks
解决方案
You could try to set explicitly the type blob with columnDefinition attribute. Like this:
@Column(name="PAYLOAD",columnDefinition="blob")
Or use the @Lob annotation:
@Column(name="PAYLOAD")    
@Lob(type = LobType.BLOB)


                        
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