JAVA File 쓰기, 이어쓰기, 개행 후 이어쓰기

import java.io.*; import java.util.*; class test {  public static void main(String[] args)  {   String str = "12345";   try   {     File file = new File("test.txt");    input (file,str,"hmmm");     // new = 새로 쓰기, old = 붙여서 이어 쓰기, else = 한줄 개행한 후 이어서 쓰기    System.out.println(output(file));   }   catch (Exception e)   {    System.out.println(e);   }  }

static void input (File file,String str,String mode) {      int fileLen = fileLength(file);   String fileOut = output(file);   try   {    BufferedWriter buffWrite = new BufferedWriter(new FileWriter(file));    if (mode.equals("new"))    {         buffWrite.write(str,0,str.length());     buffWrite.flush();    }else if(mode.equals("old")) {     str = fileOut + str;     buffWrite.write(str,0,str.length());     buffWrite.flush();    }else if(mode.equals("else")) {     str = fileOut + "\n" + str;     buffWrite.write(str,0,str.length());     buffWrite.flush();    }else { // else와 같은 기능 다른 방법의 코딩     buffWrite.write(fileOut,0,fileLen);     if (fileLen != 0) {      buffWrite.newLine();     }     buffWrite.write(str,0,str.length());     buffWrite.flush();    }    buffWrite.close();   }   catch (Exception e)   {    System.out.println(e);   }  }

static int fileLength (File file) {   int b,count = 0;   try   {      BufferedReader buffRead = new BufferedReader(new FileReader(file));    while ((b = buffRead.read()) != -1) {     count++;    }    buffRead.close();     }   catch (Exception e)   {    System.out.println(e);   }   return count;  }

static String output (File file) {    int b;    String fileContent = "";    try    {        BufferedReader buffRead = new BufferedReader(new FileReader(file));     while ((b = buffRead.read()) != -1) {      fileContent += (char)b;     }     buffRead.close();     }    catch (Exception e)    {     System.out.println(e);    }    return fileContent;   } }