java - 将 System.Out.Println 写入文本文件

Question

我需要将这些 System.out.printlns 写入文本文件，但我不知道这是如何发生的，所以我需要高级人员的帮助。

  System.out.println("You have have entered "+EnteredNumbers+ " numbers!");
  System.out.println("You have have entered "+Positive+ " Positive numbers!");
  System.out.println("The Average of the Positive Numebers is "+AveragePositive+ "!");
  System.out.println("You have have entered "+Negative+ " Negative numbers!");
  System.out.println("The Sum of the Negative numbers is "+NegativeSum+ "!");

这是完整的代码:

import java.io.*; 

public class Nums { 
  public static void main(String args[]) 
    throws IOException 
  { 
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); 
    String str;
    int EnteredNumbers = -1;
    int Positive = 0;
    int Negative = 0;
    int NegativeSum = 0;
    int PositiveSum = 0; 
    double AveragePositive = 0;

    System.out.println("Enter '0' to quit."); 
    System.out.println("Enter Numbers: "); 
   try{
    do { 
      EnteredNumbers++;
      str = br.readLine();
      int num = Integer.parseInt(str);
      if (num>0)
      {
        Positive++;
        PositiveSum+=num;
      }
      else if (num<0)
      {
        Negative++;
        NegativeSum+=num;
      }
       } 
    while(!str.equals("0")); 
      AveragePositive = (double)PositiveSum/(double)Positive;  
      System.out.println("You have have entered "+EnteredNumbers+ " numbers!");
      System.out.println("You have have entered "+Positive+ " Positive numbers!");
      System.out.println("The Average of the Positive Numebers is "+AveragePositive+ "!");
      System.out.println("You have have entered "+Negative+ " Negative numbers!");
      System.out.println("The Sum of the Negative numbers is "+NegativeSum+ "!");

      }
    catch (java.lang.NumberFormatException ex)
    {
        System.out.println("Invalid Format!");
    }  
} 
}

我是初学者，我很想获得一些帮助!

Answer 1

System.out 是写入标准输出的 PrintStream。您需要创建一个 FileOutputStream 并用 PrintStream 装饰它(或者更好的 FileWriter 和 PrintWriter):

File file = new File("C:/file.txt");
FileWriter fw = new FileWriter(file);
PrintWriter pw = new PrintWriter(fw);
pw.println("Hello World");
pw.close();

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