/*** File類：文件的創建、刪除、重命名、得到路徑、創建時間等，是唯一與文件本身有關的操作類*/ public class Main {public static void main(String[] args) {//File.separator 表示分隔符File f1 = new File("c:" + File.separator + "fuck" + File.separator + "javaTest1.txt");String s1 = File.pathSeparator; //路徑分隔符System.out.println(File.separator + " " + s1);boolean b1 = f1.exists(); //文件是否存在 System.out.println(b1);if (!b1) {try {boolean bt1 = f1.createNewFile(); //創建文件 System.out.println(bt1);} catch (IOException e) {e.printStackTrace();}}System.out.println(f1.delete()); //刪除文件//System.out.println(""); 快捷鍵：打sout,然后中按Tab鍵 System.out.println(f1.getParent()); //得到文件的上一級路徑 System.out.println(f1.isDirectory()); //判斷是否是目錄 File f2 = new File("c:" + File.separator + "fuck" + File.separator);String[] fname = f2.list(); //列出文件夾中的所有文件名for(String i:fname) System.out.println(i);File[] files = f2.listFiles(); //列出文件中的所有文件，以file數組返回for(File i:files) System.out.println(i.getName()+" "+i.length());File f3 = new File("c:\\fuck\\JavaTest1"); System.out.println(f3.mkdir()); //創建文件夾 f3.delete();System.out.println(f3.renameTo(new File("c:\\fuck\\JavaTest2"))); //重命名 } }

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/*** 在某個目錄中找到某個擴展名的所有文件*/ public class Main {private static int num = 0;public static void findFile(File f,String extName){if(f==null)return;else{if(f.isDirectory()){File[] fs = f.listFiles();if(fs!=null){for(File i:fs)findFile(i,extName);}}else{String path = f.getPath().toLowerCase();if(path.endsWith(extName)){System.out.println(f.getPath());++num;}}}}public static void main(String[] args) {File f = new File("c:\\fuck\\");String extName = ".cpp";findFile(f,extName);System.out.println(num);} }

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/*** IO流：輸入輸出流* 流：一組有順序的，有起點和終點的字節集合，是對數據傳輸的總稱或抽象。* 流的本質是數據傳輸，根據數據傳輸特性將流抽象為各種類，方便更直觀的進行數據操作。* 根據處理數據類型的不同分為：1.字符流 2.字節流* 根據數據流向不同分為：1.輸入流(程序從外部讀取) 2.輸出流（程序將數據寫到外部）* * OutputStream類：接受輸出字節并將這些字節發送到某個接收器*/ public class Main {public static void main(String[] args) {//write1(); write2();System.out.println("finished.");}/*** 字節輸出流方式一：每次輸出一個字節*/public static void write1(){OutputStream out = null;try {out = new FileOutputStream("c:\\fuck\\javaTest1.txt");String info = "helloIO";byte[] bs = info.getBytes();for(int i=0;i<bs.length;++i)out.write(bs[i]);} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();} finally {try {out.close();} catch (IOException ex) {ex.printStackTrace();}}}/*** 字節輸出流方式二：每次輸出指定大小字節*/public static void write2(){OutputStream out = null;try {out = new FileOutputStream("c:\\fuck\\javaTest1.txt",true); //參數true表示追加輸出 String info = "hello fish7";byte[] bs = info.getBytes();//out.write(bs);out.write(bs,0,5);} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();} finally {try {out.close();} catch (IOException ex) {ex.printStackTrace();}}} }

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public class Main {public static void main(String[] args) {//read1(); // read2(); read3();System.out.println("finished.");}/*** 字節輸入流的讀取方式一：每次讀取一個字節*/public static void read1(){InputStream in = null;try {in = new FileInputStream("c:\\fuck\\javaTest1.txt");int bs = -1; //定義一個字節，-1表示沒有數據while((bs = in.read())!=-1){System.out.print((char)bs); }System.out.println("");} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();} finally{try {in.close();} catch (IOException ex) {ex.printStackTrace();}}}/*** 字節輸入流的讀取方式二：一次性讀取所有字節（適合不太大的文件）*/public static void read2(){InputStream in = null;try {File f = new File("c:\\fuck\\javaTest1.txt");in = new FileInputStream(f);byte[] bs = new byte[(int)f.length()]; //根據文件大小構造字節數組int len = in.read(bs);System.out.println(new String(bs));System.out.println("len = "+len);} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();} finally{try {in.close();} catch (IOException ex) {ex.printStackTrace();}}}/*** 字節輸入流的讀取方式三：每次讀取指定大小的字節（折中的方法）*/public static void read3(){InputStream in = null;try {File f = new File("c:\\fuck\\javaTest1.txt");in = new FileInputStream(f);byte[] bs = new byte[5];int len = -1; //每次讀取的實際長度StringBuilder sb = new StringBuilder();while((len=in.read(bs))!=-1){sb.append(new String(bs,0,len));}System.out.println(sb);} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();} finally{try {in.close();} catch (IOException ex) {ex.printStackTrace();}}} }

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/*** 字符流：底層也是用字節流實現的*/ public class Main {public static void main(String[] args) {writer1();System.out.println("finished.");}/*** 字符輸出流方式一：以字符數組方式輸出*/public static void writer1(){Writer out = null;try {File f = new File("c:\\fuck\\javaTest1.txt");out = new FileWriter(f,true); //true表示追加方式 String info = "good good study, day day up.";//out.write(info.toCharArray()); out.write(info);} catch (IOException ex) {ex.printStackTrace();} finally{try{out.close();} catch (IOException ex) {ex.printStackTrace();}}} }

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/*** 字符流：底層也是用字節流實現的*/ public class Main {public static void main(String[] args) {//byteReader(); //輸出一堆亂碼 reader1();System.out.println("finished.");}/*** 字符輸入流方式一：使用指定大小的字符數組輸入*/public static void reader1(){File f = new File("c:\\fuck\\javaTest1.txt");try {Reader in = new FileReader(f);char[] cs = new char[10];int len = -1;StringBuilder sb = new StringBuilder();while((len=in.read(cs))!=-1){sb.append(new String(cs,0,len));}in.close();System.out.println(sb);} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();}}/*** 使用字節流讀取文本文件*/public static void byteReader(){File f = new File("c:\\fuck\\javaTest1.txt");try {InputStream in = new FileInputStream(f);byte[] bs = new byte[10];int len = -1;StringBuilder sb = new StringBuilder();while((len=in.read(bs))!=-1){sb.append(new String(bs,0,len));}in.close();System.out.println(sb);} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();}} }

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/*** 字符流：底層也是用字節流實現的* ：根據指定的編碼，將1個或多個字節轉化為java里的unicode字符，然后進行操作* 字符操作一般用Writer,Reader等，字節操作一般用InputStream,OutputStream以及各種包裝類，比如：* BufferedInputStream和BufferedOutputStream等* 總結：如果你確認你要處理的流是可打印的字符，那么使用字符流會簡單些，如果不確認，那么用字節流總是不會錯的。*/ public class Main {public static void main(String[] args) {//byteReader(); //輸出一堆亂碼 reader1();System.out.println("finished.");}/*** 字符輸入流方式一：使用指定大小的字符數組輸入*/public static void reader1(){File f = new File("c:\\fuck\\javaTest1.txt");try {Reader in = new FileReader(f);char[] cs = new char[10];int len = -1;StringBuilder sb = new StringBuilder();while((len=in.read(cs))!=-1){sb.append(new String(cs,0,len));}in.close();System.out.println(sb);} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();}}/*** 使用字節流讀取文本文件*/public static void byteReader(){File f = new File("c:\\fuck\\javaTest1.txt");try {InputStream in = new FileInputStream(f);byte[] bs = new byte[10];int len = -1;StringBuilder sb = new StringBuilder();while((len=in.read(bs))!=-1){sb.append(new String(bs,0,len));}in.close();System.out.println(sb);} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();}} }

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/*** 指定一個盤符下的文件，把該文件復制到指定的目錄下。*/ public class Main {public static void main(String[] args) {copyFile("c:\\fuck\\javaTest1.txt","c:\\fuck\\javaTest2.txt");copyFile("c:\\fuck\\ning.bmp","c:\\fuck\\ning2.txt"); //把.txt改成.bmp就可以看了System.out.println("finished.");}public static void copyFile(String src,String des){File f1 = new File(src);File f2 = new File(des);InputStream in = null;OutputStream out = null;try {in = new FileInputStream(f1);out = new FileOutputStream(f2);byte[] bs = new byte[105];int len = -1;while((len=in.read(bs))!=-1){out.write(bs,0,len);}} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();} finally{try {in.close();out.close();} catch (IOException ex) {ex.printStackTrace();}}} }

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/*** 轉換流：將一個字節流轉換為字符流，也可以將一個字符流轉換為字節流* OutputStreamWriter：可以將輸出的字符流轉換為字節流的輸出形式，可使用指定的charset將要寫入流* 中的字符編碼成字節。* InputStreamReader：將輸入的字節流轉換為字符流輸入形式，使用指定的charset讀取字節并將其解碼為* 字符。*/ public class Main {public static void main(String[] args) {//writer(); reader();System.out.println("finished.");}public static void writer(){ //把字符流轉成字節流try {OutputStream out = new FileOutputStream("c:\\fuck\\javaTest1.txt"); String info = "你好嗎abc.";Writer w1 = new OutputStreamWriter(out); //通過字節輸出流構造一個字符輸出流 w1.write(info);w1.close();out.close();} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();}}public static void reader(){ //把字節流轉成字符流try {InputStream in = new FileInputStream("c:\\fuck\\javaTest1.txt"); Reader r1 = new InputStreamReader(in);char[] cs = new char[105];int len = -1;StringBuilder sb = new StringBuilder();while((len=r1.read(cs))!=-1){sb.append(new String(cs,0,len));}r1.close();in.close();System.out.println(sb);} catch (FileNotFoundException ex) {ex.printStackTrace();} catch (IOException ex) {ex.printStackTrace();}} }

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轉載于:https://www.cnblogs.com/fish7/p/4149726.html

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