一、前言

关于apache的ftpserver的核心源码包ftpserver-core中org.apache.ftpserver.util.IoUtils输入输出工具类，对获取缓存输入输出流getBufferedInputStream/getBufferedOutputStream/getBufferedReader/getBufferedWriter、获取唯一的文件getUniqueFile、将异常Throwable转换为字符串getStackTrace、各个输入输出通道的复制转换 copy、指定目录或文件的删除处理delete/deleteDir/deleteFile等。

二、源码说明

package org.apache.ftpserver.util;@b@@b@import java.io.BufferedInputStream;@b@import java.io.BufferedOutputStream;@b@import java.io.BufferedReader;@b@import java.io.BufferedWriter;@b@import java.io.File;@b@import java.io.IOException;@b@import java.io.InputStream;@b@import java.io.InputStreamReader;@b@import java.io.OutputStream;@b@import java.io.PrintWriter;@b@import java.io.Reader;@b@import java.io.StringWriter;@b@import java.io.Writer;@b@import java.util.Random;@b@@b@public class IoUtils@b@{@b@  private static final Random RANDOM_GEN = new Random(System.currentTimeMillis());@b@@b@  public static final BufferedInputStream getBufferedInputStream(InputStream in)@b@  {@b@    BufferedInputStream bin = null;@b@    if (in instanceof BufferedInputStream)@b@      bin = (BufferedInputStream)in;@b@    else@b@      bin = new BufferedInputStream(in);@b@@b@    return bin;@b@  }@b@@b@  public static final BufferedOutputStream getBufferedOutputStream(OutputStream out)@b@  {@b@    BufferedOutputStream bout = null;@b@    if (out instanceof BufferedOutputStream)@b@      bout = (BufferedOutputStream)out;@b@    else@b@      bout = new BufferedOutputStream(out);@b@@b@    return bout;@b@  }@b@@b@  public static final BufferedReader getBufferedReader(Reader reader)@b@  {@b@    BufferedReader buffered = null;@b@    if (reader instanceof BufferedReader)@b@      buffered = (BufferedReader)reader;@b@    else@b@      buffered = new BufferedReader(reader);@b@@b@    return buffered;@b@  }@b@@b@  public static final BufferedWriter getBufferedWriter(Writer wr)@b@  {@b@    BufferedWriter bw = null;@b@    if (wr instanceof BufferedWriter)@b@      bw = (BufferedWriter)wr;@b@    else@b@      bw = new BufferedWriter(wr);@b@@b@    return bw;@b@  }@b@@b@  public static final File getUniqueFile(File oldFile)@b@  {@b@    File newFile = oldFile;@b@    while (true) {@b@      if (!(newFile.exists()))@b@        break;@b@@b@      newFile = new File(oldFile.getAbsolutePath() + '.' + Math.abs(RANDOM_GEN.nextLong()));@b@    }@b@@b@    return newFile;@b@  }@b@@b@  public static final void close(InputStream is)@b@  {@b@    if (is != null)@b@      try {@b@        is.close();@b@      }@b@      catch (Exception ex)@b@      {@b@      }@b@  }@b@@b@  public static final void close(OutputStream os)@b@  {@b@    if (os != null)@b@      try {@b@        os.close();@b@      }@b@      catch (Exception ex)@b@      {@b@      }@b@  }@b@@b@  public static final void close(Reader rd)@b@  {@b@    if (rd != null)@b@      try {@b@        rd.close();@b@      }@b@      catch (Exception ex)@b@      {@b@      }@b@  }@b@@b@  public static final void close(Writer wr)@b@  {@b@    if (wr != null)@b@      try {@b@        wr.close();@b@      }@b@      catch (Exception ex)@b@      {@b@      }@b@  }@b@@b@  public static final String getStackTrace(Throwable ex)@b@  {@b@    String result = "";@b@    if (ex != null)@b@      try {@b@        StringWriter sw = new StringWriter();@b@        PrintWriter pw = new PrintWriter(sw);@b@        ex.printStackTrace(pw);@b@        pw.close();@b@        sw.close();@b@        result = sw.toString();@b@      } catch (Exception e) {@b@        e.printStackTrace();@b@      }@b@@b@    return result;@b@  }@b@@b@  public static final void copy(Reader input, Writer output, int bufferSize)@b@    throws IOException@b@  {@b@    char[] buffer = new char[bufferSize];@b@    int n = 0;@b@    while ((n = input.read(buffer)) != -1)@b@      output.write(buffer, 0, n);@b@  }@b@@b@  public static final void copy(InputStream input, OutputStream output, int bufferSize)@b@    throws IOException@b@  {@b@    byte[] buffer = new byte[bufferSize];@b@    int n = 0;@b@    while ((n = input.read(buffer)) != -1)@b@      output.write(buffer, 0, n);@b@  }@b@@b@  public static final String readFully(Reader reader)@b@    throws IOException@b@  {@b@    StringWriter writer = new StringWriter();@b@    copy(reader, writer, 1024);@b@    return writer.toString();@b@  }@b@@b@  public static final String readFully(InputStream input)@b@    throws IOException@b@  {@b@    StringWriter writer = new StringWriter();@b@    InputStreamReader reader = new InputStreamReader(input);@b@    copy(reader, writer, 1024);@b@    return writer.toString();@b@  }@b@@b@  public static final void delete(File file) throws IOException {@b@    if (!(file.exists()))@b@      return;@b@    if (file.isDirectory())@b@      deleteDir(file);@b@    else@b@      deleteFile(file);@b@  }@b@@b@  private static final void deleteDir(File dir) throws IOException@b@  {@b@    File[] children = dir.listFiles();@b@@b@    if (children == null) {@b@      return;@b@    }@b@@b@    for (int i = 0; i < children.length; ++i) {@b@      File file = children[i];@b@      delete(file);@b@    }@b@@b@    if (!(dir.delete()))@b@      throw new IOException("Failed to delete directory: " + dir);@b@  }@b@@b@  private static final void deleteFile(File file)@b@    throws IOException@b@  {@b@    if (!(file.delete()))@b@    {@b@      if (OS.isFamilyWindows())@b@        System.gc();@b@      try@b@      {@b@        Thread.sleep(10L);@b@      } catch (InterruptedException e) {@b@      }@b@      if (!(file.delete()))@b@        throw new IOException("Failed to delete file: " + file);@b@    }@b@  }@b@}