如何将数据文件中的数据加载到数组中并要求用户输入，然后根据用户输入查找和打印数据？

Question

I have a project where we have to take a file name zipcodes.txt and load into an array. The files format is like 08001, Alloway, Salem county where each item is on a different line by itself.

The goal is to load the data into an array of zip codes. Print the list of zip codes--including each zip codes, town, and state with the data for each zip on separate line. A method that asks the user for zip code, then either displays the data for that zip code or says the zip code was not found in the list. This is what needs to be done, I am drawing a blank here. Any ideas?

Since there has to be a main class, a ziplist class where the array is stored, and a zipcode class where the variables are stored I have managed to load the file into an array and call it in the main method. But I can't seem to figure how to implement user into my code and have like a Boolean condition to compare the input to the data in the file and then print the zip and data for the zip such as township and state.

The file is like this

08001
Alloway
Salem County
08002
Cherry Hill
Camden County
08003

With the data on their own. like 08001 is on line 1, and Alloway is on line 2.

public class ZipcodesProject {
    //Main method for the Class
    public static void main(String[] args) throws FileNotFoundException {
        boolean isPresent = false;
        Integer index=null;

        Scanner in= new Scanner(System.in);
        while(true){
            System.out.println("Please enter the zip code:");
            String input= in.nextLine();

            ZipList zipcodesObject = new ZipList();
            zipcodesObject.ZipsandProperties(); 
            Integer number = Integer.valueOf(input);

        }
    }
}

    package zipcodesproject;
    import java.io.FileNotFoundException;
    import java.io.File;
    import java.util.Scanner;

    public class ZipList {

        public void ZipsandProperties() throws FileNotFoundException{

        File zipcodes = new File("zipcodes.txt");

           Scanner inFile = new Scanner(zipcodes);
           String[]fileData=new String[4000];
           int count=0;
           while (inFile.hasNextLine()){
               fileData[++count] = inFile.nextLine();
               System.out.println(fileData[count]);
           }
        }
    }

    package zipcodesproject;

    public class ZipCodes {
        int zip;
        String township;
        String state;

        ZipCodes(int z, String tship, String ste) {
            zip = z;
            township = tship;
            state =ste;
        }
    }

Answer 1

Instead making String array named fileData, you may first parse the String that you obtain from file as zip,township and state,then you may create an array with type ZipCodes.

public void ZipsandProperties() throws FileNotFoundException{

    File zipcodes = new File("zipcodes.txt");

       Scanner inFile = new Scanner(zipcodes);
       ZipCodes[] fileData= new ZipCodes[4000];
       int count=0;
       while (inFile.hasNextLine()){
           String line = inFile.nextLine();
           String [] temp = line.split(" ");//I assumed that your file content is like "<zip code> <township> <state>"
           ZipCodes zc = new ZipCodes(Integer.parseInt(temp[0]),temp[1],temp[2]));
           fileData[++count] = zc;
       }
    }

Then,you can use this array more flexible than String array. You can iterate it with given input.

Answer 2

i dont know if this is good enough for you, or at least it guides you into a solution you need:

ZipCodeProject.java:

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class ZipCodeProject {

    public static void main(String[] args) {

        String zipFileNamePath = "path/to/your/file/zipcodes.txt";
        try {
            List<ZipCode> zipCodes = loadZipFile(zipFileNamePath);
            int option = -1;
            Scanner optionScanner = new Scanner(System.in);
            while(option != 4) {

                printMenu();
                option = optionScanner.nextInt();
                switch (option) {
                    case 1:
                        for (ZipCode zipCode : zipCodes) {
                            System.out.println(zipCode.toString());
                        }
                        break;
                    case 2:
                        // logic to find a zip code
                        break;
                    case 3:
                        System.out.println("operation not supported");
                        break;
                    case 4:
                        System.out.println("Byeee");
                        break;
                    default:
                        System.out.println("error, select a number from the menu");
                }
            }

        } catch (FileNotFoundException exception) {
            System.out.println("File not found: " + zipFileNamePath);
        }
    }

    public static void printMenu() {
        System.out.println("Menu");
        System.out.println("1 - Print all zip codes.");
        System.out.println("2 - Find a zip code.");
        System.out.println("3 - Add new zip code.");
        System.out.println("4 - Quit.");
        System.out.println("Select the menu number");
    }

    public static List<ZipCode> loadZipFile(String zipFileName) throws FileNotFoundException {

        File zipFile = new File(zipFileName);
        Scanner inFile = new Scanner(zipFile).useDelimiter("\n");
        List<ZipCode> zipCodes = new ArrayList<>();
        while (inFile.hasNextLine()) {
            String[] zipCodeProperties = new String[3];
            int count = 0;
            while (count < 3) {
                zipCodeProperties[count] = inFile.next();
                count++;
            }
            ZipCode zipCode = new ZipCode(Integer.parseInt(zipCodeProperties[0]), zipCodeProperties[1], zipCodeProperties[2]);
            zipCodes.add(zipCode);
        }
        return zipCodes;
    }

}

ZipCode.java:

public class ZipCode {

    private int zip;
    private String town;
    private String state;

    public ZipCode(int zip, String town, String state) {
        this.zip = zip;
        this.town = town;
        this.state = state;
    }

    @Override
    public String toString() {
        return "ZipCode{" +
                "zip=" + zip +
                ", town='" + town + '\'' +
                ", state='" + state + '\'' +
                '}';
    }
}

zipcodes.txt:

08001
Alloway
Salem County
08002
Cherry Hill
Camden County

Execution:

Menu
1 - Print all zip codes.
2 - Find a zip code.
3 - Add new zip code.
4 - Quit.
Select the menu number
1
ZipCode{zip=8001, town='Alloway', state='Salem County'}
ZipCode{zip=8002, town='Cherry Hill', state='Camden County'}
Menu
1 - Print all zip codes.
2 - Find a zip code.
3 - Add new zip code.
4 - Quit.
Select the menu number
4
Byeee

I hope its helpful, any questions, just shoot :)

ps: going over the response, i noticed zip code is an int, and in your description it starts with a 0, which a leading 0 in an int is removed. If you need zip codes to be with leading 0s then you should take that variable as a String, if its just numeric, and leading 0s are not necessary to register, you can leave it as it is :D