import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.HttpURLConnection;

import java.net.MalformedURLException;

import java.net.URL;

/**

 * 文件操作的工具类

 */

public class FileUtils {

    //将一个输入流转换为一个字符串

    public static String formatStreamToString(InputStream stream){

        if(stream!=null){

            ByteArrayOutputStream out=new ByteArrayOutputStream();

            byte[] bytes=new byte[1024];

            int len=0;

            try {

                while((len=stream.read(bytes))!=-1){

                    out.write(bytes,0,len);

                }

                String str=out.toString();

                out.flush();

                out.close();

                stream.close();

                return str;

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

        return null;

    }

    //执行下载文件到指定位置

    public static void downLoadFile(final String fromPath, final String savePath, final CallBack callBack){

        if(fromPath!=null&&savePath!=null){

            new Thread(new Runnable() {

                @Override

                public void run() {

                    try {

                        URL url=new URL(fromPath);

                        HttpURLConnection conn=(HttpURLConnection) url.openConnection();

                        conn.setConnectTimeout(20*1000);

                        conn.connect();

                        InputStream input=conn.getInputStream();

                        File file=new File(savePath);

                        if(!file.getParentFile().exists())

                            file.getParentFile().mkdirs();

                        OutputStream out=new FileOutputStream(file);

                        byte[] bytes=new byte[1024];

                        for(int len=0;(len=input.read(bytes))!=-1;){

                            out.write(bytes,0,len);

                        }

                        out.flush();

                        out.close();

                        input.close();

                        callBack.success();//下载成功

                    } catch (Exception e) {

                        e.printStackTrace();

                        callBack.failed();//下载失败

                    }

                }

            }).start();

        }

    }

    public static boolean existsFile(String path){

        if(path!=null&&path.length()>0) {

            File file = new File(path);

            if(file.exists())

                return true;

        }

        return false;

    }

}