使用扫描仪读取Java文件 [英] Java read file using Scanner

问题描述

我可以使用 java.io 和 java.util.Scanner 读取文件，但是我不知道如何仅使用 java.util读取文件.扫描器:

  import java.io. *;导入java.util.Scanner;公共班级主要{公共静态void main(String [] args)引发IOException {字符串filePath ="C:\\ IdeaProjects \\ test \\ src \\ input.txt";扫描仪sc =新扫描仪(新File(filePath));整数a，b;一个= sc.nestInt();b = sc.nextInt();}} 

有人可以帮忙吗?

解决方案

由于Scanner需要一个java.io.File对象，因此我认为没有一种方法可以仅不使用任何java.io类就使用Scanner进行读取./p>

这里有两种使用Scanner类读取文件的方法-使用默认编码和显式编码.这是如何读取Java文件的长篇指南的一部分.

扫描仪-默认编码

  import java.io.File;导入java.io.FileNotFoundException;导入java.util.Scanner;公共类ReadFile_Scanner_NextLine {公共静态void main(String [] pArgs)抛出FileNotFoundException {字符串fileName ="c:\\ temp \\ sample-10KB.txt";File file = new File(fileName);试试(扫描仪扫描仪=新扫描仪(文件)){弦线;boolean hasNextLine = false;while(hasNextLine = Scanner.hasNextLine()){行= Scanner.nextLine();System.out.println(line);}}}} 

扫描仪-显式编码

  import java.io.File;导入java.io.FileNotFoundException;导入java.util.Scanner;公共类ReadFile_Scanner_NextLine_Encoding {公共静态void main(String [] pArgs)抛出FileNotFoundException {字符串fileName ="c:\\ temp \\ sample-10KB.txt";File file = new File(fileName);//使用UTF-8编码尝试(扫描仪扫描仪=新扫描仪(文件，"UTF-8")){弦线;boolean hasNextLine = false;while(hasNextLine = Scanner.hasNextLine()){行= Scanner.nextLine();System.out.println(line);}}}} 

I can read file using java.io and java.util.Scanner but I don't know how to read file using only java.util.Scanner:

import java.io.*;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws IOException {
        String filePath = "C:\\IdeaProjects\\test\\src\\input.txt";
        Scanner sc = new Scanner(new File(filePath));
        int a, b;
        a = sc.nestInt();
        b = sc.nextInt();
    }
}

Can someone help?

解决方案

Since Scanner requires a java.io.File object, I don't think there's a way to read with Scanner only without using any java.io classes.

Here are two ways to read a file with the Scanner class - using default encoding and an explicit encoding. This is part of a long guide of how to read files in Java.

Scanner – Default Encoding

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

public class ReadFile_Scanner_NextLine {
  public static void main(String [] pArgs) throws FileNotFoundException {
    String fileName = "c:\\temp\\sample-10KB.txt";
    File file = new File(fileName);

    try (Scanner scanner = new Scanner(file)) {
      String line;
      boolean hasNextLine = false;
      while(hasNextLine = scanner.hasNextLine()) {
        line = scanner.nextLine();
        System.out.println(line);
      }
    }
  }
}

Scanner – Explicit Encoding

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

public class ReadFile_Scanner_NextLine_Encoding {
  public static void main(String [] pArgs) throws FileNotFoundException {
    String fileName = "c:\\temp\\sample-10KB.txt";
    File file = new File(fileName);

    //use UTF-8 encoding
    try (Scanner scanner = new Scanner(file, "UTF-8")) {
      String line;
      boolean hasNextLine = false;
      while(hasNextLine = scanner.hasNextLine()) {
        line = scanner.nextLine();
        System.out.println(line);
      }
    }
  }
}

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