从文件中读取数字并创建数组 (java)

Question

我不知道如何将这个包含数字的 txt 文件制作成数组，我可以让它读取和打印屏幕，但我需要能够组织数字并删除重复项。这是我的代码到目前为止的样子

import java.io.BufferedReader; 
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

public class File {
 public static void main(String[] args) {
 String filename = "C:/input.txt";

 File rfe = new File();
 rfe.readFile(filename);
 }

 private void readFile(String name) {
 String input;

  try (BufferedReader reader = new BufferedReader(new FileReader(name))) {

    while((input = reader.readLine()) != null) {
        System.out.format(input); // Display the line on the monitor
    }
}
 catch(FileNotFoundException fnfe) {

 }
 catch(IOException ioe) {

 }
 catch(Exception ex) { // Not required, but a good practice

 }


}
}

Answer 1

我建议使用 ArrayList 而不是 Array。

对于数组，您甚至必须先解析列表并计算行数，然后才能对其进行初始化。 ArrayList 更加灵活，因为您不必声明要向其添加多少个值。

import java.io.BufferedReader; 
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class File {

private List<Integer> data = new ArrayList<Integer>(); //Create ArrayList

public static void main(String[] args) {
    String filename = "C:/input.txt";

    File rfe = new File();
    rfe.readFile(filename);
}

private void readFile(String name) {
    String input;

    try (BufferedReader reader = new BufferedReader(new FileReader(name))) {

        while((input = reader.readLine()) != null) {
            data.add(Integer.parseInt(input));//Add each parsed number to the arraylist
            System.out.println(input); // Display the line on the monitor
        }
    }
    catch(FileNotFoundException fnfe) {

    }
    catch(IOException ioe) {

    }
    catch(Exception ex) { // Not required, but a good practice
        ex.printstacktrace(); //Usually good for general handling
    }

}
}

从文件中读取数字并创建数组 (java)

Reading numbers from a file and creating an array (java)

java

arrays

sorting

filereader

duplicate-removal