com.cybermkd.common.util.stream.StreamReader Maven / Gradle / Ivy

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package com.cybermkd.common.util.stream;

import com.cybermkd.common.Constant;
import com.cybermkd.log.Logger;

import java.io.*;

/**
 * Created by ice on 15-1-28.
 */
public class StreamReader {

    private static final Logger logger = Logger.getLogger(StreamReader.class);

    public static String readString(InputStream is) throws IOException {
        return readString(is, Constant.encoding);
    }

    public static String readString(InputStream is, String encoding) throws IOException {
        String result = null;
        if (is != null) {
            BufferedReader rd = new BufferedReader(new InputStreamReader(is, encoding));

            StringBuilder response = new StringBuilder();
            String line;
            while ((line = rd.readLine()) != null) {
                response.append(line);
            }
            result = response.toString();
            logger.debug("Read stream from inputStream: %s", result);
            rd.close();
        }
        return result;
    }

    public static File readFile(InputStream is, File writeFile) throws IOException {
        return readFile(is, writeFile, null);
    }

    public static File readFile(InputStream is, int contentLength, File writeFile) throws IOException {
        return readFile(is, contentLength, writeFile, null);
    }

    public static File readFile(InputStream is, File writeFile, FileRenamer renamer) throws IOException {
        File file = null;
        if (is != null) {
            if (renamer != null) {
                file = renamer.rename(writeFile);
            } else {
                file = Filer.mkDirs(writeFile);
            }
            //判断文件目录是否存在 如果不存在 创建
            //获取一个写入文件流对象
            OutputStream out = new FileOutputStream(file);
            //创建一个4*1024大小的字节数组，作为循环读取字节流的临时存储空

            byte buffer[] = new byte[4 * 1024];
            int len = -1;
            //循环读取下载的文件到buffer对象数组中
            while ((len = is.read(buffer)) != -1) {
                //把文件流写入到文件
                out.write(buffer, 0, len);
            }
            out.close();
        }
        return file;
    }

    public static File readFile(InputStream is, int contentLength, File writeFile, FileRenamer renamer) throws IOException {
        File file = null;
        if (is != null) {
            //判断文件是否存在
            if (renamer == null && writeFile.exists()) {
                if (contentLength == 0) {
                    logger.warn("File download was complete, don't download " + writeFile.getPath());
                    return writeFile;
                }
                long start = writeFile.length();
                //必须要使用
                RandomAccessFile out = new RandomAccessFile(writeFile, "rw");
                out.seek(start);
                byte[] buffer = new byte[1024];
                int len = -1;
                while ((len = is.read(buffer)) != -1) {
                    out.write(buffer, 0, len);
                }
                out.close();
                file = writeFile;
            } else {
                file = readFile(is, writeFile, renamer);
            }
        }
        return file;
    }

}