如何在olingo v2中处理BLOB和CLOB？

Question

Here在olingo jpa中有关于如何处理BLOB和CLOB的伪代码。我将所需的导入添加到伪代码中：

package me;

import java.sql.Blob;
import java.sql.Clob;
import java.sql.SQLException;

import javax.sql.rowset.serial.SerialException;

import org.apache.olingo.odata2.jpa.processor.api.OnJPAWriteContent;
import org.apache.olingo.odata2.jpa.processor.api.exception.ODataJPARuntimeException;

public class OnDBWriteContent implements OnJPAWriteContent {

    @Override
    public Blob getJPABlob(byte[] binaryData) throws ODataJPARuntimeException {
        try {
            return new JDBCBlob(binaryData);
        } catch (SerialException e) {
            ODataJPARuntimeException.throwException(ODataJPARuntimeException.INNER_EXCEPTION, e);
        } catch (SQLException e) {
            ODataJPARuntimeException.throwException(ODataJPARuntimeException.INNER_EXCEPTION, e);
        }
        return null;
    }

    @Override
    public Clob getJPAClob(char[] characterData) throws ODataJPARuntimeException {
        try {
            return new JDBCClob(new String(characterData));
        } catch (SQLException e) {
            ODataJPARuntimeException.throwException(ODataJPARuntimeException.INNER_EXCEPTION, e);
        }
        return null;
    }
}

唯一的问题是我找不到任何用于JDBCBlob和JDBCClob的实现。关于如何实现它们或使用某些类，有什么建议吗？

Answer 1

如果您使用的是MySQL，那么它需要一个额外的ExceptionInterceptor以及Blob实现。您可以拥有一个自定义的ExceptionInterceptor实现，并使用它来初始化Blob字段。

实现该目标的代码如下所示

import java.sql.Blob;
import java.sql.Clob;
import java.util.Properties;

import org.apache.olingo.odata2.jpa.processor.api.OnJPAWriteContent;
import org.apache.olingo.odata2.jpa.processor.api.exception.ODataJPARuntimeException;

import com.mysql.cj.exceptions.ExceptionInterceptor;
import com.mysql.cj.log.Log;

public class CustomOnJPAWriteContent implements OnJPAWriteContent {

    @Override
    public Blob getJPABlob(byte[] binaryData) throws ODataJPARuntimeException {
        return new com.mysql.cj.jdbc.Blob(binaryData, exceptionInterceptor);
    }

    @Override
    public Clob getJPAClob(char[] characterData) throws ODataJPARuntimeException {
        
        return new com.mysql.cj.jdbc.Clob(new String(characterData), exceptionInterceptor);

    }

    ExceptionInterceptor exceptionInterceptor = new ExceptionInterceptor() {

        @Override
        public Exception interceptException(Exception sqlEx) {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public ExceptionInterceptor init(Properties props, Log log) {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public void destroy() {
            // TODO Auto-generated method stub

        }
    };

}