How Java reads files and writes to files (simple instance) _java

Java Code

public class ReadFromFile {/** * reads files in bytes and is often used to read binary files, such as pictures, sounds, images, and so on. 
    */public static void Readfilebybytes (String filename) {File File = new file (fileName); 
    InputStream in = null; 
      try {System.out.println (reads the contents of the file in bytes, one byte at a time: "); 
      Read one byte at a time in = new FileInputStream (file); 
      int tempbyte; 
      while ((Tempbyte = In.read ())!=-1) {System.out.write (tempbyte); 
    } in.close (); 
      catch (IOException e) {e.printstacktrace (); 
    Return 
      try {System.out.println (read the contents of the file in bytes, read multiple bytes at a time: "); 
      Read multiple bytes at a time byte[] tempbytes = new byte[100]; 
      int byteread = 0; 
      in = new FileInputStream (fileName); 
      Readfromfile.showavailablebytes (in); Reads multiple bytes into a byte array, byteread the number of bytes read in while (Byteread = In.read (tempbytes))!=-1) {System.out.write (tempbyt 
      ES, 0, byteread); 
    } catch (Exception E1) {e1.printstacktrace (); } finally {if (in!= null) {try {in.close (); The catch (IOException E1) {}}}/** * reads files in characters, often used for reading text, numbers, and other types of files/public stat 
    IC void Readfilebychars (String filename) {File File = new file (fileName); 
    Reader reader = null; 
      try {System.out.println (reads the contents of the file in characters, one byte at a time: "); 
      Read one character at a time reader = new InputStreamReader (new FileInputStream (file)); 
      int Tempchar; 
        while ((Tempchar = Reader.read ())!=-1) {//for Windows, \ r \ n These two characters together indicate a newline. 
        However, if the two characters are displayed separately, the lines will be changed two times. So, block \ r, or block \ n. 
        Otherwise, there will be a lot more empty lines. 
        if ((char) tempchar)!= ' \ R ') {System.out.print ((char) tempchar); 
    } reader.close (); 
    catch (Exception e) {e.printstacktrace (); 
      try {System.out.println (read the contents of the file in characters, read multiple bytes at a time: "); 
      Read multiple characters at a time char[] Tempchars = new CHAR[30]; 
      int charread = 0; Reader =New InputStreamReader (FileName) (new FileInputStream); 
        Reads more than one character into an array of characters, charread as the number of read characters while (Charread = Reader.read (tempchars))!=-1) {//also shielded \ R does not display if ((Charread = = tempchars.length) && (tempchars[tempchars.length-1]!= ' \ R ')) {Syste 
        M.out.print (Tempchars); else {for (int i = 0; i < Charread i++) {if (tempchars[i] = ' \ r ') {Contin 
            Ue 
            else {System.out.print (tempchars[i]); 
    catch (Exception E1) {E1.printstacktrace ()}}}} 
        finally {if (reader!= null) {try {reader.close (); The catch (IOException E1) {}}}/** * Reads a file in a behavior unit and is often used to read a line-oriented format file/public static 
    void Readfilebylines (String fileName) {File File = new file (fileName); 
    BufferedReader reader = null; try {System.ouT.println ("read the contents of the file in a behavioral unit, read one whole line at a time:"); 
      reader = new BufferedReader (new FileReader (file)); 
      String tempstring = null; 
      int line = 1; Read one row at a time until you read null for file end while ((tempstring = Reader.readline ())!= null) {//Show line number System.out.pri 
        Ntln ("line" + Line + ":" + tempstring); 
      line++; 
    } reader.close (); 
    catch (IOException e) {e.printstacktrace (); 
        finally {if (reader!= null) {try {reader.close (); ' Catch (IOException E1) {}}}}/** * Random Read file content */public static void Readfileby 
    Randomaccess (String fileName) {randomaccessfile randomfile = null; 
      try {System.out.println ("read the contents of a file randomly:"); 
      Open a random Access file stream, read-only randomfile = new Randomaccessfile (FileName, "R"); 
      File length, byte number long filelength = Randomfile.length (); Read the starting position of the file int beginindex = (Filelength > 4)? 
      4:0; //move the start position of the read file to the Beginindex location. 
      Randomfile.seek (Beginindex); 
      byte[] bytes = new BYTE[10]; 
      int byteread = 0; 
      Read 10 bytes at a time and read the remaining bytes if the file content is less than 10 bytes. Assigns a read number of bytes to Byteread while ((byteread = randomfile.read (bytes))!=-1) {System.out.write (bytes, 0, byte 
      Read); 
    } catch (IOException e) {e.printstacktrace (); 
        finally {if (randomfile!= null) {try {randomfile.close (); The catch (IOException E1) {}}}/** * Displays the number of bytes left in the input stream * * private static void ShowA 
    Vailablebytes (InputStream in) {try {System.out.println (the number of bytes in the current byte input stream is: + in.available ()); 
    catch (IOException e) {e.printstacktrace (); 
    } public static void Main (string[] args) {String fileName = ' c:/temp/newtemp.txt '; 
    Readfromfile.readfilebybytes (FileName); 
    Readfromfile.readfilebychars (FileName); Readfromfile.readfilebylines (FileName);
    Readfromfile.readfilebyrandomaccess (FileName); } 
}

Java Code

public class Appendtofile {/** * A method Append file: Using randomaccessfile/public static void Appendmethoda (String fil ename, String content) {try {//Open a random Access file stream, read-write Randomaccessfile randomfile = new Randomaccessfile ( 
      FileName, "RW"); 
      File length, byte number long filelength = Randomfile.length (); 
      Moves the write file pointer to the end of the file. 
      Randomfile.seek (filelength); 
      Randomfile.writebytes (content); 
    Randomfile.close (); 
    catch (IOException e) {e.printstacktrace (); 
    /** * B method Append file: Using FileWriter */public static void Appendmethodb (string fileName, string content) { 
      try {//Open a write file, the second argument in the constructor is true to write the file in append form FileWriter writer = new FileWriter (FileName, true); 
      Writer.write (content); 
    Writer.close (); 
    catch (IOException e) {e.printstacktrace (); 
    } public static void Main (string[] args) {String fileName = ' c:/temp/newtemp.txt '; String content = "New append!"; 
    Append file Appendtofile.appendmethoda (filename, content) by method A; Appendtofile.appendmethoda (FileName, "append end.") 
    \ n "); 
    Displays the contents of the file Readfromfile.readfilebylines (fileName); 
    Append file Appendtofile.appendmethodb (filename, content) by method B; Appendtofile.appendmethodb (FileName, "append end.") 
    \ n "); 
  Displays the contents of the file Readfromfile.readfilebylines (fileName); } 
}

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