postgresql错误不良的类型值:long解决方法

postgresql错误“org.postgresql.util.PSQLException: 不良的类型值 long ”解决方法：

以下是PostgreSQL抛出例外处的日志片段：

Caused by: org.postgresql.util.PSQLException: 不良的类型值 long : \x0040010346504d4e00000001000003900101000000000000000002800000028001f4007d000202040000000200000000000000000000000000000000000000005041
        at org.postgresql.jdbc.PgResultSet.toLong(PgResultSet.java:2860)
        at org.postgresql.jdbc.PgResultSet.getLong(PgResultSet.java:2114)
        at org.postgresql.jdbc.PgResultSet.getBlob(PgResultSet.java:418)
        at org.postgresql.jdbc.PgResultSet.getBlob(PgResultSet.java:405)
        at org.apache.commons.dbcp.DelegatingResultSet.getBlob(DelegatingResultSet.java:565)
        at org.apache.commons.dbcp.DelegatingResultSet.getBlob(DelegatingResultSet.java:565)
        at org.hibernate.type.descriptor.sql.BlobTypeDescriptor$1.doExtract(BlobTypeDescriptor.java:48)
        at org.hibernate.type.descriptor.sql.BasicExtractor.extract(BasicExtractor.java:47)
        at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:258)
        at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:254)
        at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:244)
        at org.hibernate.type.AbstractStandardBasicType.hydrate(AbstractStandardBasicType.java:327)
        at org.hibernate.persister.entity.AbstractEntityPersister.hydrate(AbstractEntityPersister.java:2775)
        at org.hibernate.loader.plan.exec.process.internal.EntityReferenceInitializerImpl.loadFromResultSet(EntityReferenceInitializerImpl.java:305)
        ... 64 more

解决方法：

在最底层的PostgreSQL81Dialect（藏的太深了），在getSqlTypeDescriptorOverride()接口中找到对应的内容，而且发现默认的oid + bigobject方式是在此定义的。于是重写该接口：

@Override  
    public SqlTypeDescriptor getSqlTypeDescriptorOverride(int sqlCode)  
    {  
        SqlTypeDescriptor descriptor;  
        switch (sqlCode)  
        {  
        case Types.BLOB:  
            // Force BLOB binding. Otherwise, byte[] fields annotated  
            // with @Lob will attempt to use  
            // BlobTypeDescriptor.PRIMITIVE_ARRAY_BINDING. Since the  
            // dialect uses oid for Blobs, byte arrays cannot be used.  
            //descriptor = BlobTypeDescriptor.BLOB_BINDING;  
            descriptor = BlobTypeDescriptor.STREAM_BINDING;  
            break;  
        case Types.CLOB:  
            //descriptor = ClobTypeDescriptor.CLOB_BINDING;  
            descriptor = ClobTypeDescriptor.STREAM_BINDING;  
            break;  
        default:  
            descriptor = super.getSqlTypeDescriptorOverride(sqlCode);  
            break;  
        }  
        return descriptor;  
    }

推荐使用二进制数组方式存取LOB，而不是默认的oid + bigobject；

如果抛错信息“不良的类型值”后是long，几乎可断定是LOB调用模式的问题；如果是其它类型，需进一步分析。

如果直接用JDBC，对LOB的调用接口是setBinaryStream()、setCharacterStream()等。

推荐：PostgreSQL教程