Question

我需要打开文件，但它在主函数中给出了一个错误我试图让用户但文件名如果不正确，程序将给出错误消息并终止程序这是我的计划。

//import java.io.File;

//import java.io.PrintWriter;

import java.util.Scanner;

import java.io.*; // file input/output

import java.io.IOException;

public class Stock{
String name;
String symbol;
double Price;

//Random randomNumbers = new Random();//Generate random numbers

  Stock(){ // no-argument constructor 
    name="";
    symbol="";
    Price=0.0;
  }

  Stock(String n,String s,double p){ //constructor with argument
    name=n;
    symbol=s;
    Price=p;
  }
  public void setname(String name){//mutators to set the value of name
     this.name=name;    
  }
  public void setsymbol(String symbol){//mutators to set the value of symbol 
        this.symbol=symbol; 
    }
  public void setnextPrice(double price){
        this.Price = price;     
    }
  public String getname(){//accessor to get the name

        return name;
    }

  public String getsymbol(){ //accessor to get the symbol
         return symbol;
    }
  public double getPrice(){//accessor to get currentPrice
        return Price;

    }


public void openfile()throws IOException{
    String f="";
    System.out.print("Please enter the file name: "+f);
    if (f.equals("stocks.txt")){
        Scanner x;
        x= new Scanner(new File("stocks.txt"));

        //PrintWriter outputFile = new PrintWriter("output.txt");

            String name = x.nextLine();

            System.out.println(name);

    }   
else{

    System.out.println("File Not Found");   
        return; 
        }
    }
}

Answer 1

我假设您正在尝试读取名为stocks.txt的文件并逐行获取其内容，您可以通过多种方式执行此操作

使用Files API

import java.nio.file.Files; import java.nio.file.Paths;

列出行= Files.readAllLines（Paths.get（uri）， Charset.defaultCharset（））;

遍历此列表并获取内容

使用扫描仪

        File file = new File("stock.txt");

        input = new Scanner(file);


        while (input.hasNextLine()) {
            String line = input.nextLine();
            System.out.println(line);
        }
        input.close();

使用

    File file = new File("stocks.txt");
    FileInputStream fis = null;
    BufferedInputStream bis = null;
    DataInputStream dis = null;

    try {
        fis = new FileInputStream(file);

        bis = new BufferedInputStream(fis);
        dis = new DataInputStream(bis);

        while (dis.available() != 0) {
            System.out.println(dis.readLine());
        }

    }
    catch (..) {}

你可以使用其中一种方法来实现它，使用Files API更容易。

无法在java程序中打开文件

1 个答案: