DownloadController.java
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package top.panll.assist.controller;
import io.swagger.v3.oas.annotations.Operation;
import io.swagger.v3.oas.annotations.Parameter;
import io.swagger.v3.oas.annotations.tags.Tag;
import org.apache.catalina.connector.ClientAbortException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import top.panll.assist.dto.UserSettings;
import top.panll.assist.utils.PageInfo;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Map;
@Controller
@RequestMapping("/download")
public class DownloadController {
private final static Logger logger = LoggerFactory.getLogger(DownloadController.class);
@Autowired
private UserSettings userSettings;
/**
* 获取app+stream列表
*
* @return
*/
@GetMapping(value = "/**")
@ResponseBody
public void download(HttpServletRequest request, HttpServletResponse response) {
String resourcePath = request.getServletPath();
System.out.println(resourcePath);
resourcePath = resourcePath.substring("/download".length() + 1, resourcePath.length());
String record = userSettings.getRecord();
// if (record.endsWith("/")) {
// record = record.substring(0, record.length() - 1);
// System.out.println(record);
// }
System.out.println(record + resourcePath);
File file = new File(record + resourcePath);
if (!file.exists()) {
response.setStatus(HttpServletResponse.SC_NOT_FOUND);
return;
}
/**
* 参考实现来自： CSDN 进修的CODER SpringBoot Java实现Http方式分片下载断点续传+实现H5大视频渐进式播放
* https://blog.csdn.net/lovequanquqn/article/details/104562945
*/
String range = request.getHeader("Range");
logger.info("current request rang:" + range);
//开始下载位置
long startByte = 0;
//结束下载位置
long endByte = file.length() - 1;
logger.info("文件开始位置：{}，文件结束位置：{}，文件总长度：{}", startByte, endByte, file.length());
//有range的话
if (range != null && range.contains("bytes=") && range.contains("-")) {
range = range.substring(range.lastIndexOf("=") + 1).trim();
String[] ranges = range.split("-");
try {
//判断range的类型
if (ranges.length == 1) {
// 类型一：bytes=-2343,
if (range.startsWith("-")) {
endByte = Long.parseLong(ranges[0]);
}
//类型二：bytes=2343-
else if (range.endsWith("-")) {
startByte = Long.parseLong(ranges[0]);
}
}
//类型三：bytes=22-2343
else if (ranges.length == 2) {
startByte = Long.parseLong(ranges[0]);
endByte = Long.parseLong(ranges[1]);
}
} catch (NumberFormatException e) {
startByte = 0;
endByte = file.length() - 1;
logger.error("Range Occur Error,Message:{}", e.getLocalizedMessage());
}
}
// 要下载的长度
long contentLength = endByte - startByte + 1;
// 文件名
String fileName = file.getName();
// 文件类型
String contentType = request.getServletContext().getMimeType(fileName);
// 解决下载文件时文件名乱码问题
byte[] fileNameBytes = fileName.getBytes(StandardCharsets.UTF_8);
fileName = new String(fileNameBytes, 0, fileNameBytes.length, StandardCharsets.ISO_8859_1);
response.setHeader("Content-Type", contentType);
response.setHeader("Content-Length", String.valueOf(contentLength));
//inline表示浏览器直接使用，attachment表示下载，fileName表示下载的文件名
response.setHeader("Content-Disposition", "inline;filename=" + fileName);
response.setContentType(contentType);
if (range != null) {
//各种响应头设置
//支持断点续传，获取部分字节内容：
response.setHeader("Accept-Ranges", "bytes");
//http状态码要为206：表示获取部分内容
response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
// Content-Range，格式为：[要下载的开始位置]-[结束位置]/[文件总大小]
response.setHeader("Content-Range", "bytes " + startByte + "-" + endByte + "/" + file.length());
} else {
response.setStatus(HttpServletResponse.SC_OK);
}
BufferedOutputStream outputStream = null;
RandomAccessFile randomAccessFile = null;
//已传送数据大小
long transmitted = 0;
try {
randomAccessFile = new RandomAccessFile(file, "r");
outputStream = new BufferedOutputStream(response.getOutputStream());
byte[] buff = new byte[4096];
int len = 0;
randomAccessFile.seek(startByte);
//warning：判断是否到了最后不足4096（buff的length）个byte这个逻辑（(transmitted + len) <= contentLength）要放前面
//不然会会先读取randomAccessFile，造成后面读取位置出错;
while ((transmitted + len) <= contentLength && (len = randomAccessFile.read(buff)) != -1) {
outputStream.write(buff, 0, len);
transmitted += len;
}
//处理不足buff.length部分
if (transmitted < contentLength) {
len = randomAccessFile.read(buff, 0, (int) (contentLength - transmitted));
outputStream.write(buff, 0, len);
transmitted += len;
}
outputStream.flush();
response.flushBuffer();
randomAccessFile.close();
logger.info("下载完毕：" + startByte + "-" + endByte + "：" + transmitted);
} catch (ClientAbortException e) {
logger.warn("用户停止下载：" + startByte + "-" + endByte + "：" + transmitted);
//捕获此异常表示拥护停止下载
} catch (IOException e) {
e.printStackTrace();
logger.error("用户下载IO异常，Message：{}", e.getLocalizedMessage());
} finally {
try {
if (randomAccessFile != null) {
randomAccessFile.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}///end try
}
}