#include <string>
#include <iostream>
#include <exception>
using namespace std;
#import "c:\Program Files\Common Files\System\ADO\msado15.dll" no_namespace rename("EOF", "EndOfFile"),rename("BOF", "BeforeOfFile")
#define COM_START if(!SUCCEEDED(CoInitializeEx(NULL,COINIT_MULTITHREADED))) throw exception("初始化COM错误!");
#define COM_END CoUninitialize();
////////////////////
// 记录集
void testRecordSet_Binary();
void GetRecordSet_BinaryValue( _RecordsetPtr & m_AdoRecordSet, const char * name, std::string & retValue );
////////////////////
// 存储过程
void testProcedure_Binary();
void AddInParameter( _CommandPtr & m_CommandPtr, const char * name, long value );
void AddOutBinaryParameter( _CommandPtr & m_CommandPtr, const char * name, const char * buffer, long length );
void ExecProc( _CommandPtr & m_CommandPtr, const char * ProcName );
void GetProcedure_BinaryValue( _CommandPtr & m_CommandPtr, const char * name, std::string & retValue );
int _tmain( int argc, _TCHAR * argv[] )
{
COM_START
testRecordSet_Binary();
testProcedure_Binary();
COM_END
return 0;
}
////////////////////
// 记录集
void testRecordSet_Binary()
{
_ConnectionPtr m_ConnectionPtr;
m_ConnectionPtr.CreateInstance( __uuidof( Connection ) );
m_ConnectionPtr->Open( _bstr_t ( "Driver=MySql ODBC 5.2a Driver;Server=127.0.0.1;Database=test;UID=test;PWD=123456" ),
"", "", adConnectUnspecified );
_RecordsetPtr m_AdoRecordSet;
m_AdoRecordSet.CreateInstance( __uuidof( Recordset ) );
m_AdoRecordSet->PutRefActiveConnection( m_ConnectionPtr );
m_AdoRecordSet->Open( "select * from bintable22 where id=1", m_AdoRecordSet->GetActiveConnection(), adOpenDynamic, adLockOptimistic, adCmdText );
string value;
GetRecordSet_BinaryValue( m_AdoRecordSet, "bin", value );
cout << value << "结束" << endl;
}
void GetRecordSet_BinaryValue( _RecordsetPtr & m_AdoRecordSet, const char * name, std::string & retValue )
{
FieldPtr fpr = m_AdoRecordSet->GetFields()->GetItem( name );
long length = fpr->ActualSize;
if( length > 0 )
{
_variant_t varBLOB;
_StreamPtr stream;
stream.CreateInstance( "ADODB.Stream" );
_variant_t varOptional( DISP_E_PARAMNOTFOUND, VT_ERROR );
stream->raw_Open( varOptional, adModeUnknown, adOpenStreamUnspecified, NULL, NULL );
stream->put_Type( adTypeBinary );
stream->Write( fpr->GetValue() );
stream->put_Position( 0 );
varBLOB = stream->Read( adReadAll );
int len = stream->GetSize();
if( varBLOB.vt == ( VT_ARRAY | VT_UI1 ) ) ///判断数据类型是否正确
{
char * pBuf = NULL;
SafeArrayAccessData( varBLOB.parray, ( void ** )&pBuf );
retValue = std::string( pBuf, pBuf + length );
SafeArrayUnaccessData( varBLOB.parray );
}
stream->Close();
}
}
////////////////////
// 存储过程
void testProcedure_Binary()
{
_ConnectionPtr m_ConnectionPtr;
m_ConnectionPtr.CreateInstance( __uuidof( Connection ) );
m_ConnectionPtr->Open( _bstr_t ( "Driver=MySql ODBC 5.2a Driver;Server=127.0.0.1;Database=test;UID=test;PWD=123456" ),
"", "", adConnectUnspecified );
_CommandPtr m_CommandPtr;
m_CommandPtr.CreateInstance( __uuidof( Command ) );
m_CommandPtr->PutRefActiveConnection( m_ConnectionPtr );
long id = 1;
//string bin( 16, 'x' ); // 测试该行，没问题。
string bin( 4, 'y' ); // 测试该行，有问题，引发了我写的异常。如果将我的异常那行代码删去，则最终得到的结果只有前 4 个字节。
//string bin; // 测试该行，在 AddOutBinaryParameter 的时候就挂了。如果对于空 string ，改为 AddOutBinaryParameter( ..., "\0", 1 ); 那就像上一行一样，结果只有一个字节。
AddInParameter( m_CommandPtr, "id", id );
AddOutBinaryParameter( m_CommandPtr, "bin", bin.c_str(), bin.size() );
ExecProc( m_CommandPtr, "GetBinInfo22" );
string value;
GetProcedure_BinaryValue( m_CommandPtr, "bin", value );
cout << value << "结束" << endl;
}
void AddInParameter( _CommandPtr & m_CommandPtr, const char * name, long value )
{
m_CommandPtr->Parameters->Append( m_CommandPtr->CreateParameter( _bstr_t( name ), adInteger, adParamInput, 4, value ) );
}
void AddOutBinaryParameter( _CommandPtr & m_CommandPtr, const char * name, const char * buffer, long length )
{
char * buf = const_cast< char * >( buffer );
VARIANT varBLOB;
SAFEARRAY * psa;
SAFEARRAYBOUND rgsabound[1];
rgsabound[0].lLbound = 0;
rgsabound[0].cElements = length;
psa = SafeArrayCreate( VT_UI1, 1, rgsabound ); ///创建SAFEARRAY对象
for( long i = 0; i < length; i++ )
SafeArrayPutElement( psa, &i, buf++ ); ///将pBuf指向的二进制数据保存到SAFEARRAY对象psa中
varBLOB.vt = VT_ARRAY | VT_UI1;///将varBLOB的类型设置为BYTE类型的数组
varBLOB.parray = psa; ///为varBLOB变量赋值
m_CommandPtr->Parameters->Append( m_CommandPtr->CreateParameter( _bstr_t( name ), adVarBinary, adParamOutput, length, varBLOB ) );
SafeArrayDestroy( psa );
}
void ExecProc( _CommandPtr & m_CommandPtr, const char * ProcName )
{
m_CommandPtr->CommandText = _bstr_t( ProcName );
m_CommandPtr->CommandType = adCmdStoredProc;
m_CommandPtr->Execute( NULL, NULL, adCmdStoredProc );
}
void GetProcedure_BinaryValue( _CommandPtr & m_CommandPtr, const char * name, string & retValue )
{
_ParameterPtr ppr = m_CommandPtr->Parameters->GetItem( _bstr_t( name ) );
long ExpectMaxLen = ppr->GetSize();
if( ExpectMaxLen > 0 )
{
_variant_t varBLOB;
_StreamPtr stream;
stream.CreateInstance( "ADODB.Stream" );
_variant_t varOptional( DISP_E_PARAMNOTFOUND, VT_ERROR );
stream->raw_Open( varOptional, adModeUnknown, adOpenStreamUnspecified, NULL, NULL );
stream->put_Type( adTypeBinary );
stream->Write( ppr->GetValue() );
stream->put_Position( 0 );
varBLOB = stream->Read( adReadAll );
int ActualLen = stream->GetSize();
if( ActualLen > ExpectMaxLen )
{
// AddOutBinaryParameter 时提供的长度就是 ExpectMaxLen 的值
// ActualLen 是字段实际的有效内容的长度(无论 ExpectMaxLen 比 ActualLen 大还是小)，也是 varBLOB.parray 的长度
// 当 ExpectMaxLen 设置得不够大时，varBLOB.parray 就只有前 ExpectMaxLen 个字节有正确的内容
// 例如字段实际的内容为 7 字节长
// AddOutBinaryParameter( ..., 16 )，则 ExpectMaxLen 的值是 16，ActualLen 的值是 7，varBLOB.parray 的 7 个字节均为有效数据
// AddOutBinaryParameter( ..., 4 )，则 ExpectMaxLen 的值是 4，ActualLen 的值是 7，varBLOB.parray 的 7 个字节中，前 4 个字节为有效数据，后 3 个字节的值为 \0 或乱码
throw exception( "期望获得较小的长度，而实际上字段的有效内容的长度较大，没有取得全部数据!" );
}
if( varBLOB.vt == ( VT_ARRAY | VT_UI1 ) ) ///判断数据类型是否正确
{
char * pBuf = NULL;
SafeArrayAccessData( varBLOB.parray, ( void ** )&pBuf );
retValue = std::string( pBuf, pBuf + ActualLen );
SafeArrayUnaccessData( varBLOB.parray );
}
stream->Close();
}
}
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