com.cybermkd.route.render.FileRender Maven / Gradle / Ivy

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package com.cybermkd.route.render;

import com.cybermkd.common.Render;
import com.cybermkd.common.http.ContentType;
import com.cybermkd.common.http.HttpRequest;
import com.cybermkd.common.http.HttpResponse;
import com.cybermkd.common.http.exception.WebException;
import com.cybermkd.common.http.result.HttpStatus;
import com.cybermkd.log.Logger;

import java.io.*;

/**
 * Created by wangrenhui on 15/1/4.
 */
public class FileRender extends Render {
    private static final Logger logger = Logger.getLogger(FileRender.class);

    public void render(HttpRequest request, HttpResponse response, Object out) {
        if (out != null) {
            File file = null;
            BufferedInputStream bis = null;
            if (out instanceof String) {
                file = new File((String) out);
            } else if (out instanceof File) {
                file = (File) out;
            }

            if (file == null) {
                throw new WebException(HttpStatus.NOT_FOUND, "File not support '" + out + "'.");
            } else if (!file.exists()) {
                throw new WebException(HttpStatus.NOT_FOUND, "File not found '" + file.getName() + "'.");
            } else {
                try {
                    long p = 0L;
                    long toLength = 0L;
                    long contentLength = 0L;
                    int rangeSwitch = 0; // 0,从头开始的全文下载；1,从某字节开始的下载（bytes=27000-）；2,从某字节开始到某字节结束的下载（bytes=27000-39000）
                    long fileLength;
                    String rangBytes = "";
                    fileLength = file.length();

                    // get file content
                    InputStream ins = new FileInputStream(file);
                    bis = new BufferedInputStream(ins);

                    // tell the client to allow accept-ranges
                    response.reset();
                    response.setHeader("Accept-Ranges", "bytes");

                    // client requests a file block download start byte
                    String range = request.getHeader("Range");
                    if (range != null && range.trim().length() > 0 && !"null".equals(range)) {
                        response.setStatus(HttpStatus.PARTIAL_CONTENT);
                        rangBytes = range.replaceAll("bytes=", "");
                        if (rangBytes.endsWith("-")) {  // bytes=270000-
                            rangeSwitch = 1;
                            p = Long.parseLong(rangBytes.substring(0, rangBytes.indexOf("-")));
                            contentLength = fileLength - p;  // 客户端请求的是270000之后的字节（包括bytes下标索引为270000的字节）
                        } else { // bytes=270000-320000
                            rangeSwitch = 2;
                            String temp1 = rangBytes.substring(0, rangBytes.indexOf("-"));
                            String temp2 = rangBytes.substring(rangBytes.indexOf("-") + 1, rangBytes.length());
                            p = Long.parseLong(temp1);
                            toLength = Long.parseLong(temp2);
                            contentLength = toLength - p + 1; // 客户端请求的是 270000-320000 之间的字节
                        }
                    } else {
                        contentLength = fileLength;
                    }

                    // 如果设设置了Content-Length，则客户端会自动进行多线程下载。如果不希望支持多线程，则不要设置这个参数。
                    // Content-Length: [文件的总大小] - [客户端请求的下载的文件块的开始字节]
                    response.setHeader("Content-Length", Long.toString(contentLength));

                    // 断点开始
                    // 响应的格式是:
                    // Content-Range: bytes [文件块的开始字节]-[文件的总大小 - 1]/[文件的总大小]
                    if (rangeSwitch == 1) {
                        String contentRange = "bytes " + Long.toString(p) + "-" + Long.toString(fileLength - 1) + "/" + Long.toString(fileLength);
                        response.setHeader("Content-Range", contentRange);
                        bis.skip(p);
                    } else if (rangeSwitch == 2) {
                        String contentRange = range.replace("=", " ") + "/" + Long.toString(fileLength);
                        response.setHeader("Content-Range", contentRange);
                        bis.skip(p);
                    } else {
                        String contentRange = "bytes " + "0-" + (fileLength - 1) + "/" + fileLength;
                        response.setHeader("Content-Range", contentRange);
                    }

                    String fileName = file.getName();
                    response.setContentType(ContentType.FILE.value());
                    response.addHeader("Content-Disposition", "attachment;filename=" + fileName);

                    OutputStream outputStream = response.getOutputStream();
                    int n = 0;
                    long readLength = 0;
                    int bsize = 1024;
                    byte[] bytes = new byte[bsize];
                    if (rangeSwitch == 2) {
                        // 针对 bytes=27000-39000 的请求，从27000开始写数据
                        while (readLength <= contentLength - bsize) {
                            n = bis.read(bytes);
                            readLength += n;
                            outputStream.write(bytes, 0, n);
                        }
                        if (readLength <= contentLength) {
                            n = bis.read(bytes, 0, (int) (contentLength - readLength));
                            outputStream.write(bytes, 0, n);
                        }
                    } else {
                        while ((n = bis.read(bytes)) != -1) {
                            outputStream.write(bytes, 0, n);
                        }
                    }
                    bis.close();
                } catch (IOException ie) {
                    // 忽略 ClientAbortException 之类的异常
                } catch (Exception e) {
                    throw new WebException(e.getMessage());
                }
            }
        }
    }
}