java - 从文件中读取特定行并将数据与一行分开

Question

我是 java 的新手，所以任何帮助将不胜感激。

我正在尝试编写一个程序，询问用户要读取哪个文件，然后询问 ID，在文件中搜索该 ID，然后从该行输出信息。它将读取的文本文件格式如下:

Apple^201^3

香蕉^202^4

橙色^205^5

2nd 列用于 ID。

我还需要将信息分开一些，这样我才能像这样输出它:

元素:苹果

ID:201:

价格:3 美元

import java.util.*;
import java.io.*;
public class fruit
{
   public static void main(String[] args) throws IOException
{
  Scanner keyboard = new Scanner(System.in);

  System.out.println("Enter a filename >> ");
  String filename = keyboard.nextLine();

  File f = new File(filename);
  Scanner fin = new Scanner(f);

  System.out.println("Enter item ID: ");
  int fruitID = keyboard.nextInt();

  while(fin.hasNextLine())
  {
      String line = fin.nextLine();

      if(fin.hasNextInt(fruitID))
      {
          System.out.println(line);
      }
      else
      {
          System.out.println("ERROR");
      }
   }
      fin.close();
  }
}

Answer 1

Hope this will help


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

public class FindGivenStringFromFile {

    public static void main(String args[]) throws FileNotFoundException {

        Scanner keyboard = new Scanner(System.in);

        System.out.println("Enter a filename >> ");
        String filename = keyboard.nextLine();

        File f = new File(filename);
        Scanner fin = new Scanner(f);

        System.out.println("Enter item ID: ");
        int fruitID = keyboard.nextInt();

        //Reading each line of file using Scanner class
        int lineNumber = 1;
        while (fin.hasNextLine()) {
            String line = fin.nextLine();
            String[] lineDataArray = line.split("\\^");
            if(lineDataArray != null && lineDataArray.length >2){
                if(Integer.parseInt(lineDataArray[1]) == fruitID){
                    System.out.println("Item: " + lineDataArray[0]);
                    System.out.println("Id: " + lineDataArray[1]);
                    System.out.println("price: $" + lineDataArray[2]);
                }

            lineNumber++;
        }       

    }   
}
}