SetCharacterEncoding 
filters.SetCharacterEncodingFilter 
encoding 
GBK 
SetCharacterEncoding 
*.do 

while(rs.next())
{
string col1=rs.getString(1);
string col2=rs.getString(2);
string col3=rs.getString(3);
float col4=rs.getFloat(4);
col1=new string(col1.getBytes("iso-8859-1"),"GB2312");
col2=new string(col2.getBytes("iso-8859-1"),"GB2312");
col3=new string(col3.getBytes("iso-8859-1"),"GB2312");
----
}