请帮帮忙，看看这个JAVA BEAN啊

试试:
sql="select * from tbinvoicebook";if((startcode != null) && (endcode != null)){
  if((!startcode.equals("")) && (endcode.equals(""))){
     sql=sql+" where " + startcode+" between vcstartcode and vcfinishcode";
  }
  if((startcode.equals("")) && (!endcode.equals(""))){
     sql=sql+" where " + endcode+" between vcstartcode and vcfinishcode";
  }  try{
  ......
}