比较TextFields与文件混淆

Question

我正在制作一个交换应用程序，但我变得沮丧并且遇到了一些麻烦。我知道我需要做什么，但为了到达那里我迷失了，如果这是有道理的。我只需要帮助我们获取结果的步骤，没有直接的代码。方向说＆＃34;从提供的文本文件[currency.txt]中搜索textFields [CurrencyTo和CurrencyFrom]中输入的国家/地区的三个字母的货币代码。例如，如果CurrencyFrom为“United States”，则您的代码应从currency.txt文件中找到货币代码“USD”。＆＃34;

我知道我需要（1）将文本框中的国家/地区与inputFile中的国家/地区进行比较 （2）如果相同，则获取国家代码并将其保存在变量中。 我需要采取的任何建议或细分都是我正在寻找的。请不要直接代码！谢谢

 class ButtonListener implements ActionListener
    {
        public void actionPerformed(ActionEvent event)
        {                 
            if(event.getSource()==calculateButton){
            String from = currencyFrom.getText();
            String to = currencyTo.getText();
            try{
            String line = "";
            File inputFile = new File("currency.txt");
            Scanner in = new Scanner(inputFile);
            try{
            while(in.hasNextLine()){
            line = in.nextLine();
            String[] lineContent = line.split("\t");
            System.out.println(Arrays.toString(lineContent));
            System.out.println(lineContent[0] + lineContent[1]);
            //compare the country in the textbox with the country from the inputFile
            //if they are the same, then get the country code and save it in a variable

            }
            }  
            finally{ in.close();
            }
            } 
            catch (FileNotFoundException ex) {
            displayLabel.setText("File not found");}

            //go to the website and get exchagne rate and do the calculation
            String line = "";
            String address = "http://finance.yahoo.com/d/quotes.csv?e=.csv&f=sl1d1t1&s=" + from + to + "=X";
            try{
            URL pageLocation = new URL(address);
        Scanner in = new Scanner(pageLocation.openStream());
            try{
            while (in.hasNextLine()){
            line = in.nextLine();
            System.out.println(line);
            String[] data = line.split(",");
            System.out.println(Arrays.toString(data));
            System.out.println(data[0] + data[1] + data[2] + data[3]);
            //display calculation
            displayLabel.setText("");
            //display last update
            updateLabel.setText("Last Updated: " + data[2] + data[3]);
            }
            }
            finally{ in.close();
            }
            }
            catch (MalformedURLException exception){
            displayLabel.setText("Website not found!");} 
            catch (IOException ex) {}

            if(event.getSource()==clearButton){
                currencyTo.setText("");
                currencyFrom.setText("");
                amount.setText("100");
                displayLabel.setText("");
                updateLabel.setText("");
            }
        }
    }  
}
        //add listener to the buttons
        ActionListener listener = new ButtonListener();
        clearButton.addActionListener(listener);
        calculateButton.addActionListener(listener);

}
}