DataSource datasource;
BufferedReader d=new BufferedReader(new InputStreamReader(System.in));
String bookname;
while(!("exit".equals(bookname = d.readline()))){
    Connection con = datasource.getConnection()
    Statement stmt = con.createStatement();
    ResultSet res = stmt.executeQuery("select * from testtable where bookname= '" + bookname + "'"); 
    if(res.next()){
        System.out.println("价格为："+res.getDouble("price"));
    }//if 结束
}//while 结束