像PHP一樣的文件寫入/讀取功能

Question

所以我在Java中每天都在學習新的東西，並且我希望有一天我會在Java中擁有和PHP相同的知識。

我試圖做一個類，它是類似於fopen，fwrite，fclose在PHP中，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! 
?> 

我也需要寫

Ø的方法 - 進行刪除和寫/覆蓋

a - 用於追加末尾

和一個讀取函數，它會逐行返回內容，所以我可以把它放到一個數組中，如file_get_contents（file）;

這是我迄今爲止...

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); 
    } 
} 

也，我不明白爲什麼我必須

readwrite_txt test = new readwrite_txt(fileName,encoding); 

，而不是

readwrite_txt test = new readwrite_txt(); 

我只是想要有一個類似於PHP的簡單函數。

EDITED

所以我的函數必須是

$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

看一看下面的文件處理教程（谷歌充斥着他們）：

• http://www.javapractices.com/topic/TopicAction.do?Id=42
• http://www.coderanch.com/t/403914/java/java/do-read-entire-file-all

，請注意以下類：

• 的FileInputStream
• FileOutpuStream
• 掃描儀

有各種各樣的例子在那裏，供您學習。

Answer 2

在Java中讀取一個文件就可以了

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readwrite_txt test = new readwrite_txt();問題.. 你必須在類中的另一個構造函數不帶任何參數

Answer 3

您可以使用BufferedReader，here是一個例子，但是BufferedWriter，here是寫的一個例子，here是附加的例子。對於逐行讀取，您可以使用BufferedReader的readLine方法。你不需要這些參數在你的構造函數中，因爲你不使用它們，但你甚至不需要一個類來實現這些特性，因爲已經有了用於這個目的的標準類。

我希望這會有所幫助。