java文件创建、删除、读取、写入操作大全详解编程语言

     public String getInputMessage() throws IOException...{ 
         System.out.println("请输入您的命令∶"); 
         byte buffer[]=new byte[1024]; 
         int count=System.in.read(buffer); 
         char[] ch=new char[count-2];//最后两位为结束符，删去不要 
         for(int i=0;i<count-2;i++) 
             ch[i]=(char)buffer[i]; 
         String str=new String(ch); 
         return str; 
     }

     public void copyFile(String src,String dest) throws IOException...{ 
         FileInputStream in=new FileInputStream(src); 
         File file=new File(dest); 
         if(!file.exists()) 
             file.createNewFile(); 
         FileOutputStream out=new FileOutputStream(file); 
         int c; 
         byte buffer[]=new byte[1024]; 
         while((c=in.read(buffer))!=-1)...{ 
             for(int i=0;i<c;i++) 
                 out.write(buffer[i]);         
         } 
         in.close(); 
         out.close(); 
     }

    public void PrintStreamDemo()...{ 
         try ...{ 
             FileOutputStream out=new FileOutputStream("D:/test.txt"); 
             PrintStream p=new PrintStream(out); 
             for(int i=0;i<10;i++) 
                 p.println("This is "+i+" line"); 
         } catch (FileNotFoundException e) ...{ 
             e.printStackTrace(); 
         } 
     }

public void StringBufferDemo() throws IOException......{ 
         File file=new File("/root/sms.log"); 
         if(!file.exists()) 
             file.createNewFile(); 
         FileOutputStream out=new FileOutputStream(file,true);         
         for(int i=0;i<10000;i++)......{ 
             StringBuffer sb=new StringBuffer(); 
             sb.append("这是第"+i+"行:前面介绍的各种方法都不关用,为什么总是奇怪的问题 "); 
             out.write(sb.toString().getBytes("utf-8")); 
         }         
         out.close(); 
}

     public void renameFile(String path,String oldname,String newname)...{ 
         if(!oldname.equals(newname))...{//新的文件名和以前文件名不同时,才有必要进行重命名 
             File oldfile=new File(path+"/"+oldname); 
             File newfile=new File(path+"/"+newname); 
             if(newfile.exists())//若在该目录下已经有一个文件和新文件名相同，则不允许重命名 
                 System.out.println(newname+"已经存在！"); 
             else...{ 
                 oldfile.renameTo(newfile); 
             } 
         }          
     }

     public void changeDirectory(String filename,String oldpath,String newpath,boolean cover)...{ 
         if(!oldpath.equals(newpath))...{ 
             File oldfile=new File(oldpath+"/"+filename); 
             File newfile=new File(newpath+"/"+filename); 
             if(newfile.exists())...{//若在待转移目录下，已经存在待转移文件 
                 if(cover)//覆盖 
                     oldfile.renameTo(newfile); 
                 else 
                     System.out.println("在新目录下已经存在："+filename); 
             } 
             else...{ 
                 oldfile.renameTo(newfile); 
             } 
         }        
     }

public String FileInputStreamDemo(String path) throws IOException...{ 
         File file=new File(path); 
         if(!file.exists()||file.isDirectory()) 
             throw new FileNotFoundException(); 
         FileInputStream fis=new FileInputStream(file); 
         byte[] buf = new byte[1024]; 
         StringBuffer sb=new StringBuffer(); 
         while((fis.read(buf))!=-1)...{ 
             sb.append(new String(buf));     
             buf=new byte[1024];//重新生成，避免和上次读取的数据重复 
         } 
         return sb.toString(); 
     }

   
     public String BufferedReaderDemo(String path) throws IOException...{ 
         File file=new File(path); 
         if(!file.exists()||file.isDirectory()) 
             throw new FileNotFoundException(); 
         BufferedReader br=new BufferedReader(new FileReader(file)); 
         String temp=null; 
         StringBuffer sb=new StringBuffer(); 
         temp=br.readLine(); 
         while(temp!=null)...{ 
             sb.append(temp+" "); 
             temp=br.readLine(); 
         } 
         return sb.toString(); 
     }

     public Document readXml(String path) throws DocumentException, IOException...{ 
         File file=new File(path); 
         BufferedReader bufferedreader = new BufferedReader(new FileReader(file)); 
         SAXReader saxreader = new SAXReader(); 
         Document document = (Document)saxreader.read(bufferedreader); 
         bufferedreader.close(); 
         return document; 
     }

     public void createDir(String path)...{ 
         File dir=new File(path); 
         if(!dir.exists()) 
             dir.mkdir(); 
     }

     public void createFile(String path,String filename) throws IOException...{ 
         File file=new File(path+"/"+filename); 
         if(!file.exists()) 
             file.createNewFile(); 
     }

     public void delFile(String path,String filename)...{ 
         File file=new File(path+"/"+filename); 
         if(file.exists()&&file.isFile()) 
             file.delete(); 
     }

     public void delDir(String path)...{ 
         File dir=new File(path); 
         if(dir.exists())...{ 
             File[] tmp=dir.listFiles(); 
             for(int i=0;i<tmp.length;i++)...{ 
                 if(tmp[i].isDirectory())...{ 
                     delDir(path+"/"+tmp[i].getName()); 
                 } 
                 else...{ 
                     tmp[i].delete(); 
                 } 
             } 
             dir.delete(); 
         } 
     }