Java 写入文件和搜索数组时出现问题

对于任何错误，我都很抱歉，我试着做了一些更正，以便更容易理解我在做什么以及我需要什么帮助。我对java和这个网站非常陌生

我正试图编写一个程序，将在5个独立文件中找到的州（州名、州昵称、州人口、州花和州首府）数据组织到5个独立的并行数组中。代码将请求输入并向用户提供带有逗号格式的填充数据。我还创建了一个将所有信息写入输出文件的方法

我有一些问题

我想知道我是否能在一些问题上得到帮助

首先，运行代码后，文件状态_data.txt为空

其次，如果在askState方法中输入无效的选项而不是请求新的输入，我的程序就会崩溃

我将感谢任何帮助

 import java.io.File;
    import java.io.FileNotFoundException;
    import java.io.PrintWriter;
    import java.util.Scanner;

    /**
     *

     */

public class Project_3a {

    /**
     * @param args the command line arguments
     */
    static final int NUM_STATES = 50;

    public static void main(String[] args) throws FileNotFoundException {
        String[] stateNames = importFile("stateNames.txt");
        String[] nicknames = importFile("nicknames.txt");
        String[] populations = importFile("population.txt");
        String[] flowers = importFile("flowers.txt");
        String[] capital = importFile("capitals.txt");
        for (int x = 0; x < NUM_STATES; x++) 
         {

         createFile(stateNames, nicknames, capital, flowers, populations);
         char getWantsToContinue = 'y'; 
         while (getWantsToContinue == 'y' || getWantsToContinue == 'Y') 
         { 
           System.out.println(stateNames); 
           int index = askState(stateNames); 
           String unformattedPopulation = populations[index]; 
           String formattedPopulation = formatPopulation(unformattedPopulation);                   
           outPut(stateNames,nicknames, capital, flowers, formattedPopulation,index);             
         }
         getWantsToContinue = again();
    }

    public static String[] importFile(String fileName) throws
            FileNotFoundException {

        String[] array = new String[NUM_STATES];

        File inputFile = new File(fileName);
        Scanner scanner = new Scanner(inputFile);


        for (int i = 0; i < NUM_STATES; i++) {
            array[i] = scanner.nextLine();

        }
        return array;

    }

    public static int askState(String[] stateNames) {
        Scanner keyboard = new Scanner(System.in);
        String state;
        int statePosition = -1;
        System.out.println("Please enter a state that you would like to search:");
        state = keyboard.nextLine();
        {
            for (int i = 0; i < NUM_STATES; i++) {
                if (state.equals(stateNames[i])) {
                    statePosition = i;
                    return statePosition;
                }
            }
            System.out.println("Please enter a valid state:");

        }
        return statePosition;
    }

    public static String formatPopulation(String population) {
        String formattedPopulations = "";
        {
            for (int i = population.length() - 1; i >= 0; i--) {
                formattedPopulations = population.charAt(i) + formattedPopulations;
                if (i % 3 == 2 && (i + 1 != population.length())) {
                    formattedPopulations = "," + formattedPopulations;
                }
            }
            return formattedPopulations;
        }

    }

    public static void createFile(String[] stateNames, String[] nicknames,
            String[] capitals, String[] flowers, String[] populations) throws FileNotFoundException {
        PrintWriter stateData = new PrintWriter("state_data.txt");
        for (int i = 0; i < NUM_STATES; i++) {
            stateData.println(stateNames[i] + "\t" + nicknames[i] + "\t" + capitals[i]
                    + "\t" + flowers[i] + "\t" + formatPopulation(populations[i]) + "\n");
        }
        stateData.close();
    }

    public static void outPut(String[] stateNames, String[] nicknames,
            String[] capitals, String[] flowers, String formattedPopulation,
            int index) {
        System.out.println("State Name: " + stateNames[index]);
        System.out.println("Nickname: " + nicknames[index]);
        System.out.println("Capital: " + capitals[index]);
        System.out.println("Flower: " + flowers[index]);
        System.out.println("Population: " + formattedPopulation);
    }

    public static char again() {
        Scanner keyboard = new Scanner(System.in);

        char getWantsToContinue;
        System.out.println("Would you like to search another state?");
        System.out.println("Please enter Y for yes or N for no.");
        getWantsToContinue = keyboard.next().charAt(0);
        while (getWantsToContinue != 'y' && getWantsToContinue != 'Y'
                && getWantsToContinue != 'n' && getWantsToContinue != 'N') {
            System.out.println("Please enter a valid option (Yor N).");
            getWantsToContinue = keyboard.next().charAt(0);
        }
        if (getWantsToContinue == 'n' || getWantsToContinue == 'N') {
            System.out.println("Goodbye!");
        }

        return getWantsToContinue;

    }
}

导入java.io.File；
导入java.io.FileNotFoundException；
导入java.io.PrintWriter；
导入java.util.Scanner；
/**
*
*/
公共类项目(3a){
/**
*@param指定命令行参数
*/
静态最终整数状态=50；
公共静态void main（字符串[]args）引发FileNotFoundException{
字符串[]stateNames=importFile（“stateNames.txt”）；
字符串[]昵称=导入文件（“昵称.txt”）；
String[]populations=importFile（“population.txt”）；
字符串[]flowers=importFile（“flowers.txt”）；
字符串[]大写=导入文件（“capitals.txt”）；
对于（int x=0；x=0；i--）{
格式化总体=总体。字符（i）+格式化总体；
如果（i%3==2&&（i+1！=population.length（））{
formattedPopulations=“，”+formattedPopulations；
}
}
返回原始种群；
}
}
公共静态void createFile（字符串[]状态名，字符串[]昵称，
字符串[]大写字母、字符串[]花朵、字符串[]人口）引发FileNotFoundException{
PrintWriter stateData=新的PrintWriter（“state_data.txt”）；
对于（int i=0；i

我只想补充一下我在您的代码中发现的问题

（1） 。我发现的第一个问题是在函数

importFile

中

  for (int i = 0; i < NUM_STATES; i++) {
        array[i] = scanner.nextLine();

    }

（2） .我在

createFile

方法中找到了第二个问题

您正在创建一个新文件，并从所有文件中插入第一个字符。然后是第二个字符。然后是第三个字符…直到第50个字符

如果相应的文件在第50个字符之前没有任何数据该怎么办？这将在结果中输入错误的数据

(a). Read one character at a time.
(b). If you are not sure about the size of each file, iterate through it till the EOF.

     for (int x = 0; x < NUM_STATES; x++) 
         {

         **createFile(stateNames, nicknames, capital, flowers, populations);**
         char getWantsToContinue = 'y'; 
         while (getWantsToContinue == 'y' || getWantsToContinue == 'Y') 
         { 
           System.out.println(stateNames); 
           int index = askState(stateNames); 
           String unformattedPopulation = populations[index]; 
           String formattedPopulation = formatPopulation(unformattedPopulation);                   
           outPut(stateNames,nicknames, capital, flowers, formattedPopulation,index);             
         }

while(scanner.hasNext()){
scanner.next();
}

  while(scanner.hasNextLine()){
    scanner.nextLine();
    }

while(invalidState(state)){
System.out.println("Please enter input");
state = keyboard.nextLine();
}

for (int x = 0; x < NUM_STATES; x++) 
         {

         createFile(stateNames, nicknames, capital, flowers, populations);