1、基础版，通过Buffer缓冲流下载
final File file = new File(robotPath);
response.setContentType("application/force-download");
response.addHeader("Content-Disposition",
"attachment;fileName=" + java.net.URLEncoder.encode(file.getName(), "UTF-8"));
response.setContentLength((int) file.length());
final byte[] buffer = new byte[NUM1024];
FileInputStream fis = null;
BufferedInputStream bis = null;
try {
fis = new FileInputStream(file);
bis = new BufferedInputStream(fis);
final OutputStream os = response.getOutputStream();
int i = bis.read(buffer);
while (i != -1) {
os.write(buffer, 0, i);
i = bis.read(buffer);
}
System.out.println("success");
} catch (Exception e) {
e.printStackTrace();
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (fis != null) {
try {
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
2、升级版，通过FileChannel下载，下载速度更快。
File file = new File(info.getAbsolutePath());
/**
* 中文乱码解决
*/
String type = request.getHeader("User-Agent").toLowerCase();
String fileName = null;
try {
if (type.indexOf("firefox") > 0 || type.indexOf("chrome") > 0) {
/**
* 谷歌或火狐
*/
fileName = new String(fileInfo.getFileName().getBytes(charsetCode), "iso8859-1");
} else {
/**
* IE
*/
fileName = URLEncoder.encode(fileName, charsetCode);
}
// 设置响应的头部信息
response.setHeader("content-disposition", "attachment;filename=" + fileName);
// 设置响应内容的类型
response.setContentType(fileName + "; charset=" + charsetCode);
response.setContentLength((int) file.length());
// 设置响应内容的长度
response.setHeader("filename", fileName);
//通过文件管道获取飞一般的下载速度
WritableByteChannel writableByteChannel = Channels.newChannel(response.getOutputStream());
FileChannel fileChannel = new FileInputStream(file.getAbsolutePath()).getChannel();
fileChannel.transferTo(0, fileChannel.size(), writableByteChannel);
} catch (Exception e) {
System.out.println("执行downloadFile发生了异常：" + e.getMessage());
}
3、前端使用vue3.0和axios
downloadFileByConditions(row) {
const that = this;
this.downDialogProgress = true;
debugger
const url = '/com/wk/filesmanage/downloadFileController/downloadFileByConditions';
const tempParam = {
sid:row.sid,
databaseType: row.databaseType,
fileName: row.fileName,
fileType: row.fileType,
fileVersion: row.fileVersion,
ownService: row.ownService
}
const param = JSON.stringify(tempParam);
axios.post(url, param, {
responseType: "arraybuffer", headers: {
"Content-Type": "application/json;charset=utf-8"
},
onDownloadProgress(a) {
const percent = (parseInt(a.loaded) / parseInt(a.total) * 100 ).toFixed(2);
nextTick(() => {
that.progressNum = percent;
});
}
}).then(res => {// 处理返回的文件流
let blob = new Blob(
[res.data],
{
type: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8'
});
let downloadElement = document.createElement('a');
let href = window.URL.createObjectURL(blob); //创建下载的链接
downloadElement.href = href;
downloadElement.download = res.headers.filename; //下载后文件名
document.body.appendChild(downloadElement);
downloadElement.click(); //点击下载
document.body.removeChild(downloadElement); //下载完成移除元素
window.URL.revokeObjectURL(href); //释放掉blob对象
that.downDialogProgress = false;
that.progressNum = 0;
});
},
