如何在打印上一个文件后重新加载java中的其他文件

我下面的代码正在编译，但我有一个逻辑错误。好的，在我输入了我想要读取的数据后，我选择在屏幕上打印这些数据，我可以选择加载一个不同的文件。但是，当我输入要加载的新文件的名称时，它不会加载该文件以及我为该特定情况指定的错误消息。我想我必须在每次写入或类似的事情之后刷新流缓冲区。所以，如果有人能指出为什么会发生这种情况，我将不胜感激

导入java.util.Scanner； 导入java.io.*

public class Driver {
    private static int numberOfCustomer = 0;
    private static Customer[] customerList = new Customer[10];

        private static void readInCustomer(String file){
        FileReader freader;
        BufferedReader inputFile;
        try{
            freader = new FileReader(file);
            inputFile = new BufferedReader(freader);
            String strLine;


            while ((strLine = inputFile.readLine()) != null)   {
                    customerList[numberOfCustomer] = new Customer();
                    customerList[numberOfCustomer].ID = strLine;
                    customerList[numberOfCustomer].name  =                 inputFile.readLine();
                    customerList[numberOfCustomer].address  = inputFile.readLine();
                    customerList[numberOfCustomer].phone  = inputFile.readLine();
                    numberOfCustomer++;
            }

            inputFile.close();
        }catch(Exception e){
            System.out.println("Could not find file "+file+" System will now exit");
            System.exit(1);

        }

        return;
    }

        private static void printCustomer(Customer customer){
        System.out.println("The Customer Data corresponding to Customer Number " + customer.ID  + " is:");
        System.out.println("Name:\t\t\t"+customer.name);
        System.out.println("Address:\t\t"+customer.address);
        System.out.println("Telephone:\t\t"+customer.phone);
        System.out.println();
        return;
    }

        private static void printAll(){
        boolean hasID = false;
            Scanner keyboard = new Scanner(System.in);

        System.out.println("All customers from data file "+numberOfCustomer);


        System.out.println(" Here they are!!! ");
        for(int i=0; i<numberOfCustomer; i++){
            if(customerList[i] != null){
                System.out.println("The Customer Data corresponding to Customer Number " + customerList[i].ID  + " is:");
                System.out.println("Name:\t\t\t"+customerList[i].name);
                System.out.println("Address:\t\t"+customerList[i].address);
                System.out.println("Telephone:\t\t"+customerList[i].phone);
            }
        }
        if(!hasID){

        System.out.println("");
        }
        System.out.println("Would you like to go to the menu? (Y or N):");
        String input = keyboard.nextLine();
        char repeat = input.charAt(0);
         if(repeat == 'Y' || repeat == 'y'){Menu();} 
                    return;
    }

    private static void Menu(){
        boolean hasID = false;
        Scanner keyboard = new Scanner(System.in);

        System.out.println("YOU MAY CHOOSE FROM THE FOLLOWING OPTIONS:");
      System.out.println("A. SEARCH for a customer by ID number");
      System.out.println("B. DISPLAY the entire Customer List");
      System.out.println("C. RE-LOAD DATA from a different data file");
      System.out.println("D. QUIT:");

        String choice = keyboard.nextLine();

        char repeat = choice.charAt(0);
         if(repeat == 'A' || repeat == 'a'){Scostomer();} 
            if(repeat == 'B' || repeat == 'b'){printAll();}
            if(repeat == 'C' || repeat == 'c'){mainn();}
              return;

        }

   public static void Scostomer(){
    boolean hasID = false;
        Scanner keyboard = new Scanner(System.in);

        System.out.println("Type in the Id you are search for");

        String customerID = keyboard.nextLine();

        for(int i=0; i<numberOfCustomer; i++){
            if((customerList[i]!=null) && (customerID.equals(customerList[i].ID))){
                hasID = true;
                printCustomer(customerList[i]);
                i=customerList.length;
            }
        }

        if(!hasID){
            System.out.println("Sorry, customer not found.");
        }
        System.out.println("Would you like to search for another custnomer? (Y or N):");
        String input = keyboard.nextLine();
        char repeat = input.charAt(0);
         if(repeat == 'Y' || repeat == 'y'){Scostomer();} 
            if(repeat == 'N' || repeat == 'n'){Menu();}
                    return;
    }

    public static void main(String arg[]){
        Scanner keyboard = new Scanner(System.in);
            System.out.println("Enter the fileName that contains the data of your customers: ");
        readInCustomer(keyboard.nextLine());
        Menu();
        return;
        }

    public static void mainn(){
        Scanner keyboard = new Scanner(System.in);

            System.out.println("Enter the fileName that contains the data of your customers: ");
        readInCustomer(keyboard.nextLine());
        Menu();
        return;

    }
}

---

适用于我加载文件，键入c加载新文件，键入b显示所有文件。我建议文件名有一些简单的错误或愚蠢的地方，所以您应该记录异常详细信息，而不是在catch块中忽略它们

    } catch(Exception e) {
        e.printStackTrace(); // should tell you what's wrong!
        System.out.println("Could not find file "+file+" System will now exit");
        System.exit(1);

    }

冲洗在这里不相关，因为你是在阅读，而不是写作。你也可以整理一下整个菜单/输入循环，虽然有点古怪，但它确实有效！。例如，您的main和mainn方法是相同的-您是否考虑过将其抽象为单独的方法

您可以使用一个列表，而不必担心要阅读多少客户，而不是将自己限制为10个客户。我只是将您的代码更改为使用列表而不是数组：

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Driver {
    private static int numberOfCustomer = 0;
    // List instead of array!
    private static List<Customer> customerList = new ArrayList<Customer>();

    private static void readInCustomer(String file) {
        FileReader freader;
        BufferedReader inputFile;
        try {
            freader = new FileReader(file);
            inputFile = new BufferedReader(freader);
            String strLine;

            while ((strLine = inputFile.readLine()) != null) {
                Customer customer = new Customer();
                customer.ID = strLine;
                customer.name = inputFile.readLine();
                customer.address = inputFile.readLine();
                customer.phone = inputFile.readLine();
                customerList.add(customer); // add to the List!
            }

            inputFile.close();
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("Could not find file " + file
                    + " System will now exit");
            System.exit(1);

        }

        return;
    }

    private static void printCustomer(Customer customer) {
        System.out
                .println("The Customer Data corresponding to Customer Number "
                        + customer.ID + " is:");
        System.out.println("Name:\t\t\t" + customer.name);
        System.out.println("Address:\t\t" + customer.address);
        System.out.println("Telephone:\t\t" + customer.phone);
        System.out.println();
        return;
    }

    private static void printAll() {
        boolean hasID = false;
        Scanner keyboard = new Scanner(System.in);

        System.out.println("All customers from data file " + numberOfCustomer);

        System.out.println(" Here they are!!! ");
        for (Customer customer : customerList) {
            System.out
                    .println("The Customer Data corresponding to Customer Number "
                            + customer.ID + " is:");
            System.out.println("Name:\t\t\t" + customer.name);
            System.out.println("Address:\t\t" + customer.address);
            System.out.println("Telephone:\t\t" + customer.phone);
        }

        if (!hasID) {
            System.out.println("");
        }
        System.out.println("Would you like to go to the menu? (Y or N):");
        String input = keyboard.nextLine();
        char repeat = input.charAt(0);
        if (repeat == 'Y' || repeat == 'y') {
            Menu();
        }
        return;
    }

    private static void Menu() {
        boolean hasID = false;
        Scanner keyboard = new Scanner(System.in);

        System.out.println("YOU MAY CHOOSE FROM THE FOLLOWING OPTIONS:");
        System.out.println("A. SEARCH for a customer by ID number");
        System.out.println("B. DISPLAY the entire Customer List");
        System.out.println("C. RE-LOAD DATA from a different data file");
        System.out.println("D. QUIT:");

        String choice = keyboard.nextLine();

        char repeat = choice.charAt(0);
        if (repeat == 'A' || repeat == 'a') {
            Scostomer();
        }
        if (repeat == 'B' || repeat == 'b') {
            printAll();
        }
        if (repeat == 'C' || repeat == 'c') {
            mainn();
        }
        return;

    }

    public static void Scostomer() {
        boolean hasID = false;
        Scanner keyboard = new Scanner(System.in);

        System.out.println("Type in the Id you are search for");

        String customerID = keyboard.nextLine();

        // iterate over the List!
        for (Customer customer : customerList) {
            if (customerID.equals(customer.ID)) {
                hasID = true;
                printCustomer(customer);
                break;
            }
        }

        if (!hasID) {
            System.out.println("Sorry, customer not found.");
        }
        System.out
                .println("Would you like to search for another custnomer? (Y or N):");
        String input = keyboard.nextLine();
        char repeat = input.charAt(0);
        if (repeat == 'Y' || repeat == 'y') {
            Scostomer();
        }
        if (repeat == 'N' || repeat == 'n') {
            Menu();
        }
        return;
    }

    public static void main(String arg[]) {
        Scanner keyboard = new Scanner(System.in);
        System.out
                .println("Enter the fileName that contains the data of your customers: ");
        readInCustomer(keyboard.nextLine());
        Menu();
        return;
    }

    public static void mainn() {
        Scanner keyboard = new Scanner(System.in);

        System.out
                .println("Enter the fileName that contains the data of your customers: ");
        readInCustomer(keyboard.nextLine());
        Menu();
        return;

    }
}

---

尝试将“e.printStackTrace”放在readInCustomer的catch块中，然后希望您能找到问题，如果没有，请将该跟踪与您的问题放在一起？您的代码非常适合我。检查以确保您拥有正确的文件路径，并且键入的文件正确。问题是，我要加载的第二个txt文件中的字符串较长，因此我必须增加私有静态客户[]customerList=新客户[10]；到私有静态客户[]customerList=新客户[30]；哇，谢谢你！我见过e.printStackTrace；在Grad之前，它给了我这个错误java. Lang.ArayIdxOutOfFunsExpRe: 10在Reald.Read in CubjelDistabase.java：33，所以我只是把数字从10到30，它应该考虑使用一个集合，即列表，而不是数组，如果你不能保证你总是拥有最多10个客户。通常不赞成打印到System.out并使用e.printStackTrace-建议使用commmons logging、slf4j等日志框架。但是，对于快速和不干净的日志记录，或者对于独立的命令行应用程序来说，它是很好的。那么，你建议我怎么做？啊，那么，使用列表可以消除一些限制啊，好的，谢谢你，我会记得，从现在开始，弗洛姆，你帮了我很多，谢谢