来自文件路径的 Java 输入和输出流

Question

如何使用指定的文件路径而不是资源文件夹中的文件作为输入或输出流？这是我拥有的类，我想从特定文件路径读取，而不是将 txt 文件放在 IntelliJ 中的资源文件夹中。对于输出流也是如此。如有任何帮助，我们将不胜感激。

输入流

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

public class Example02 {
    public static void main(String[] args) throws FileNotFoundException {
        // STEP 1: obtain an input stream to the data

        // obtain a reference to resource compiled into the project
        InputStream is = Example02.class.getResourceAsStream("/file.txt");

        // convert to useful form
        Scanner in = new Scanner(is);

        // STEP 2: do something with the data stream
        // read contents
        while (in.hasNext()) {
            String line = in.nextLine();
            System.out.println(line);
        }

        // STEP 3: be polite, close the stream when done!
        // close file
        in.close();
    }
}

输出流

import java.io.*;

public class Example03
{
    public static void main(String []args) throws FileNotFoundException
    {
        // create/attach to file to write too
        // using the relative filename will cause it to create the file in
        // the PROJECT root
        File outFile = new File("info.txt");

        // convert to a more useful writer
        PrintWriter out = new PrintWriter(outFile);

        //write data to file
        for(int i=1; i<=10; i++)
            out.println("" + i + " x 5 = " + i*5);

        //close file - required!
        out.close();            
    }
}

Answer 1

获取InputStream的首选方式是java.nio.file.Files.newInputStream(Path)

try(final InputStream is = Files.newInputStream(Paths.get("/path/to/file")) {
    //Do something with is
}

与输出流相同Files.newOutputStream()

try(final OutputStream os = Files.newOutputStream(Paths.get("/path/to/file")) {
    //Do something with os
}

一般来说，这里是official tutorial from Oracle使用 IO。