java 下载文件(web服务器与文件服务器分离)

场景一 download from webserver ,source file come from webserver file system

/**
* 文件下载
*/
@Controller
@RequestMapping(value = "file/",method=RequestMethod.GET)
public class FileSvcController extends BaseController {

@RequestMapping("download")
public HttpServletResponse download(HttpServletRequest request, HttpServletResponse response) throws IOException {
try {
//web服务器上文件存储路径
String filePath = "d:\\星空.jpg";
java.io.File file = new java.io.File(filePath);
//在浏览器上显示的下载文件名
String fileName = "星空.jpg";

// 以流的形式下载文件。
InputStream fis = new BufferedInputStream(new FileInputStream(filePath));
byte[] buffer = new byte[fis.available()];
fis.read(buffer);
fis.close();
// 清空response
response.reset();
// 设置response的Header URLEncoder对文件名编码输出，防止中文文件名出现乱码
response.addHeader("Content-Disposition", "attachment;filename=" +java.net.URLEncoder.encode(fileName, "UTF-8"));
response.addHeader("Content-Length", "" + file.length());
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
toClient.write(buffer);
toClient.flush();
toClient.close();

} catch (IOException ex) {
ex.printStackTrace();
}
return response;

}
}

场景二 download from webserver ,source file come from remote server file system

/**
* 文件下载
*/
@Controller
@RequestMapping(value = "file/",method=RequestMethod.GET)
public class FileSvcController extends BaseController {

final static int BUFFER_SIZE = 4096;

@RequestMapping("download")
public HttpServletResponse download(HttpServletRequest request, HttpServletResponse response){
InputStream fis = null;
try {
String fileName = "星空.jpg";
String fileUrl = "http://192.168.1.105/2016/11/26/"+URLEncoder.encode("星空.jpg","UTF-8");
URL uri = new URL(fileUrl);
InputStream fileStream = uri.openStream();
// 以流的形式下载文件。
fis = new BufferedInputStream(fileStream);
byte[] buffer = InputStreamTOByte(fis);
fis.close();
// 清空response
response.reset();
// 设置response的Header
response.addHeader("Content-Disposition", "attachment;filename=" + java.net.URLEncoder.encode(fileName, "UTF-8"));
response.addHeader("Content-Length", "" + buffer.length);
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
toClient.write(buffer);
toClient.flush();
toClient.close();
} catch (IOException ex) {
ex.printStackTrace();
}
return response;
}

/**
* 循环从inputstream中读取文件流到byte数组
* 将inputstream convert to byte array
* @param in
* @return
* @throws IOException
*/
public byte[] InputStreamTOByte(InputStream in) throws IOException{
ByteArrayOutputStream outStream = null;
try {
outStream = new ByteArrayOutputStream();
byte[] data = new byte[BUFFER_SIZE];
int count = -1;
while ((count = in.read(data, 0, BUFFER_SIZE)) != -1)
outStream.write(data, 0, count);

data = null;
outStream.close();
return outStream.toByteArray();
}catch (IOException e){
throw  e;
}
finally {
if(outStream != null) outStream.close();
}
}
}

其他

测试的时候是使用自己的家用笔记本电脑(作为文件服务器)和公司配置的笔记本电脑(作为web服务器)，自己的家用笔记本电脑作为文件服务器（windows操作系统），自己的笔记本电脑可以使用Http://192.168.1.105/2016/11/26/00c62dc866ce49f8a421602c21ce61f0.pdf访问到文件，但是使用公司的电脑（ip为192.168.1.115）无法访问到Http://192.168.1.105/2016/11/26/00c62dc866ce49f8a421602c21ce61f0.pdf文件，原来是文件服务器开启了防火墙导致的，将文件服务器防火墙关闭即可正常访问文件服务器下载查看文件