Java 输出流不工作

Question

我有一个简单的设置，我想在其中写入一个名为 file.txt 的文件。但是，当我运行代码时，没有任何内容写入文件。

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintWriter;
import java.util.Scanner;

public class rand {
    public static void main(String[] args) {
    PrintWriter outputStream = null;

    try {
        outputStream = new PrintWriter(new FileOutputStream("file.txt"));
    } catch (FileNotFoundException e) {
        System.out.println("File not found");
        System.exit(0);
    }
    outputStream.println("Hello World!");
}
}

这里有什么问题？我似乎无法弄清楚。谢谢

Answer 1

您没有关闭 PrintWriter。您可以使用 try-with-resources 来解决这个问题声明，

try (outputStream = new PrintWriter(new FileOutputStream("file.txt"));) {
  outputStream.println("Hello World!");  
} catch (FileNotFoundException e) {
  System.out.println("File not found");
  System.exit(0);
}

或 finally block

try {
  outputStream = new PrintWriter(new FileOutputStream("file.txt"));
  outputStream.println("Hello World!");  
} catch (FileNotFoundException e) {
  System.out.println("File not found");
  System.exit(0);
} finally {
  outputStream.close();
}