java - 像 PHP 中的文件写入/读取功能

Question

所以我每天都在 Java 中学习新东西，我希望有一天我能在 Java 中拥有与 PHP 相同的知识。

我正在尝试创建一个类似于 PHP 中的 fopen、fwrite、fclose 的类，例如:

<?php
$fp = fopen('data.txt', 'w');
fwrite($fp, '1');
fwrite($fp, '23');
fclose($fp);

// the content of 'data.txt' is now 123 and not 23!
?>

我也需要写法

o - 用于删除和写入/覆盖

a - 用于在末尾附加

还有一个读取函数，它逐行返回内容，因此我可以将其放入数组中，例如 file_get_contents(file);

这就是我到目前为止所拥有的......

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

/** 
Read and write a file using an explicit encoding.
Removing the encoding from this code will simply cause the 
system's default encoding to be used instead.  
**/
public final class readwrite_txt 
{

    /** Requires two arguments - the file name, and the encoding to use.  **/
    public static void main(String[] args) throws IOException 
    {
        String fileName = "text.txt";
        String encoding = "UTF-8";

        readwrite_txt test = new readwrite_txt(fileName,encoding);
        test.write("argument.txt","some text","UTF-8","o");
    }

    /** Constructor. **/
    readwrite_txt(String fileName, String encoding)
    {
        String fEncoding = "text.txt";
        String fFileName = "UTF-8";
    }

    /** Write fixed content to the given file. **/
    public void write(String fileName,String input,String encoding,String writeMethod) throws IOException  
    {
        // Method overwrite
        if(writeMethod == "o")
        {
            log("Writing to file named " + fileName + ". Encoding: " + encoding);
            Writer out = new OutputStreamWriter(new FileOutputStream(fileName), encoding);
            try 
            {
                out.write(input);
            }
            finally 
            {
                out.close();
            }
        }
    }

    /** Read the contents of the given file. **/
    public void read(String fileName,String output,String encoding,String outputMethod) throws IOException 
    {
        log("Reading from file.");
        StringBuilder text = new StringBuilder();
        String NL = System.getProperty("line.separator");
        Scanner scanner = new Scanner(new FileInputStream(fileName), encoding);
        try 
        {
            while (scanner.hasNextLine())
            {
            text.append(scanner.nextLine() + NL);
            }
        }
        finally
        {
            scanner.close();
        }
        log("Text read in: " + text);
    }

    // Why write System.out... when you can make a function like log("message"); simple!
    private void log(String aMessage)
    {
    System.out.println(aMessage);
    }
}

另外，我不明白为什么我必须有

readwrite_txt test = new readwrite_txt(fileName,encoding);

而不是

readwrite_txt test = new readwrite_txt();

我只是想要一个类似于 PHP 中的简单函数。

已编辑

所以我的功能一定是

$fp = fopen('data.txt', 'w'); ==> readwrite_txt test = new readwrite_txt(filename,encoding,writeMethod);

fwrite($fp, '23');            ==> test.write("the text");

fclose($fp);                  ==> ???

Answer 1

要在java中读取文件，您可以

FileInputStream fstream = new FileInputStream("file.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(fstream));
String strLine;

while ((strLine = br.readLine()) != null) //Start of reading file
{
    //what you want to do with every line is here 
}

但是对于readwrite_txt test = new readwrite_txt();问题..类中必须有另一个不带任何参数的构造函数