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，但是我不知道如何发生，因此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+ "!");

这是整个代码：

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，很想获得帮助！

Answer 1

System.out是一个PrintStream ，它写入标准输出。 您需要创建一个FileOutputStream并用PrintStream装饰（或使用PrintWriter更好的FileWriter ）：

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

---

另请参阅：

• 这是用Java创建文件并将其写入的最佳方法。

Answer 2

这是2014年。所以这里是java.nio.file。

因此：

final List<String> list = new ArrayList<>();

list.add("first string here");
list.add("other string");
// etc etc

然后：

final Path path = Paths.get("path/to/write/to");

Files.write(path, list, StandardCharsets.UTF_8, StandardOpenOption.CREATE);

而且不要使用File 。

Answer 3

您可以使用setOut（）方法通过System.out.println（）进行文件写入； 在每次使用System.out.println（）调用setOut（）之后，sop方法将打印在文件上或您在setOut（）方法中提供的任何方法