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獲取二進制流時收到以下異常。IOException：流已關閉Hibernate MS SQL JDBC4
java.io.IOException: The stream is closed.
at com.microsoft.sqlserver.jdbc.BaseInputStream.checkClosed(SimpleInputStream.java:93)
at com.microsoft.sqlserver.jdbc.PLPInputStream.read(PLPInputStream.java:237)
at au.gov.vic.doi.tp.service.binary.dao.BinaryDAOImplTest.retrieveBinary(BinaryDAOImplTest.java:102)
我正在使用：Hibernate 4.1.1，MS SQL Server 2008和最新的MS SQL JDBC4驅動程序。 我使用以下自定義映射類型'BlobToStreamUserType'將SQL Blob（varchar（max））映射到InputStream。 Hibernate似乎沒有提供將SQL BLOB映射到Java InputStream的類型，但MaterializedBlobType只將SQL BLOB映射到Java byte []。
我正在使用'rs.getBinaryStream'返回一個真正的二進制流而不是緩衝在內存中的流，原因是我們有大圖像，如果多個用戶同時訪問會導致內存問題。
據微軟
的Microsoft驅動程序遵循JDBC規範相對於getBinaryStream => 注意：返回流中的所有數據必須得到任何>其他列的值之前被讀取。下一次調用getter方法會隱式關閉流。此外，當調用InputStream.available方法時，如果數據>可用或不可用，則stream>可能會返回0。
所以getBinaryStream被設計爲返回一個真正的字節流。我們返回一個真正的字節流，它不會緩衝在內存中，它是一個從服務器響應中直接讀取的流。您不能關閉contentDataResultSet，直到您爲我們的實現獲取所有字節。
我試着將hibernate屬性'hibernate.jdbc.use_streams_for_binary'設置爲true和false，但這沒什麼區別。
這是我的代碼：
圖像實體類顯示映射到自定義用戶類型。
import java.io.InputStream;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import org.hibernate.annotations.DynamicInsert;
import org.hibernate.annotations.DynamicUpdate;
import org.hibernate.annotations.GenericGenerator;
import org.hibernate.annotations.Type;
import com.google.common.base.Objects;
@Entity
@DynamicInsert(false)
@DynamicUpdate(false)
@Table(name = "Binary")
public class Binary
{
.........
@Lob
@Column(name = "image")
@Type(type = "my.package.BlobToStreamUserType")
public InputStream getImageStream()
{
return this.imageStream;
}
}
這裏是我的自定義映射類型：
public class BlobToStreamUserType implements UserType
{
public int[] sqlTypes()
{
return new int[]
{ Types.BLOB };
}
public Class returnedClass()
{
return InputStream.class;
}
public Object nullSafeGet(final ResultSet rs, final String[] names, final SessionImplementor session,
final Object owner) throws HibernateException, SQLException
{
return rs.getBinaryStream(names[0]);
}
public void nullSafeSet(final PreparedStatement st, final Object value, final int index,
final SessionImplementor session) throws HibernateException, SQLException
{
if (value != null)
{
if (!InputStream.class.isAssignableFrom(value.getClass()))
{
throw new HibernateException(value.getClass().toString() + " cannot be cast to a java.IO.InputStream");
}
InputStream inStream = (InputStream) value;
st.setBinaryStream(index, inStream);
}
else
{
st.setBytes(index, null);
}
}
public boolean equals(final Object x, final Object y) throws HibernateException
{
return ObjectUtils.equals(x, y);
}
public int hashCode(final Object x) throws HibernateException
{
assert (x != null);
return x.hashCode();
}
public Object deepCopy(final Object value) throws HibernateException
{
return value;
}
public boolean isMutable()
{
return false;
}
public Object replace(final Object original, final Object target, final Object owner) throws HibernateException
{
return original;
}
public Serializable disassemble(final Object value) throws HibernateException
{
//disassemble() is only called when caching the data in the second-level cache
// also safe for mutable objects
throw new UnsupportedOperationException("Not supported yet.");
}
public Object assemble(final Serializable cached, final Object owner) throws HibernateException
{
throw new UnsupportedOperationException("Not supported yet.");
}
}
，這裏是我的DAO檢索圖像流
public class BinaryDAOImpl extends AbstractSpringHibernateDAO implements BinaryDAO
{
public Binary getBinary(final String amsAssetId, final String assetMaintainer, final String variant,
final Integer sequence) throws GetException
{
try
{
Query query = super.getSession().createQuery(
"from Binary bin where bin.amsAssetId = :amsAssetId and bin.assetMaintainer = :assetMaintainer "
+ "and bin.variant = :variant and bin.sequence = :sequence");
query.setParameter("amsAssetId", amsAssetId);
query.setParameter("assetMaintainer", assetMaintainer);
query.setParameter("variant", variant);
query.setParameter("sequence", sequence);
return query.uniqueResult();
}
鈮以下解決方法休眠繞過並直接從結果集作品中檢索流，並允許我無需讀取流例外。不過，我寧願使用休眠映射來檢索一個真正的二進制流。
修改DAO方法
public Binary getBinary(final String amsAssetId, final String assetMaintainer, final String variant,
final Integer sequence) throws GetException
{
try
{
Query query = super.getSession().createQuery(
"from Binary bin where bin.amsAssetId = :amsAssetId and bin.assetMaintainer = :assetMaintainer "
+ "and bin.variant = :variant and bin.sequence = :sequence");
query.setParameter("amsAssetId", amsAssetId);
query.setParameter("assetMaintainer", assetMaintainer);
query.setParameter("variant", variant);
query.setParameter("sequence", sequence);
Binary binary = (Binary) query.uniqueResult();
final String id = binary.getId();
// Necessary until Hibernate supports InputStream mapping
binary.setImageStream(getSession().doReturningWork(new ReturningWork<InputStream>()
{
public InputStream execute(final Connection connection) throws SQLException
{
PreparedStatement statement = connection.prepareStatement("select image from Binary where id=?",
ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
statement.setString(1, id);
ResultSet resultSet = statement.executeQuery();
return (resultSet.first() ? resultSet.getBinaryStream(1) : null);
}
}));
return binary;
}