java编写Http服务器下载工具

import java.net.URL;import java.net.URLConnection;import java.io.File;import java.io.InputStream;import java.io.FileOutputStream;import java.io.FileNotFoundException;import java.io.IOException;import org.apache.commons.io.FileUtils;public class HttpUtil{  private String httppath = "";  public void setHttpPath(String httppath){    this.httppath = httppath;  }  public String getHttpPath(){    return this.httppath;  }  public HttpUtil(String httppath){    this.httppath = httppath;  }  public InputStream getStream(String url){    InputStream inStream = null;    try{      URL httpurl = new URL(url);      URLConnection conn = httpurl.openConnection();      inStream = conn.getInputStream();    }catch (Exception e){      e.printStackTrace();      return null;    }    return inStream;  }  public int downLoad(String url,String localName ,int lines) throws FileNotFoundException, IOException{    FileOutputStream fos = null;    InputStream inStream = null;    int ret = 0;    try{      URL httpurl = new URL(url);      URLConnection conn = httpurl.openConnection();      inStream = conn.getInputStream();      fos = new FileOutputStream(localName);      byte[] b = new byte[102400];      int j = 0;      while(inStream.read(b) != -1 && lines > 0){        for(int i = j; i < b.length; i++){          if(b[i] == '/n'){            fos.write(b, j, i - j + 1);            lines--;            if(lines <= 0){              break;            }            j = i + 1;            continue;          }        }      }    }catch (Exception e){      e.printStackTrace();      ret = -1;    }finally {      fos.close();      inStream.close();      return ret;    }  }  public static void main(String[] args){    String httppath = "";    int lines = 0;    String localName = "";    try{      httppath = args[0];      localName = args[1];      lines = Integer.parseInt(args[2]);    }catch (Exception e){      e.printStackTrace();      return;    }    try{      HttpUtil hu = new HttpUtil(httppath);      hu.downLoad(hu.getHttpPath(),localName ,lines);    }catch (Exception e){      e.printStackTrace();    }  }}