我有一个 Spring Boot 应用程序,在其中创建了一个 POST 方法,该方法以流方式向调用者发送数据。下面的代码:
@RequestMapping(value = "/mapmatchstreaming", method = RequestMethod.POST)
public ResponseEntity<StreamingResponseBody> handleRequest(@RequestParam(value = "data", required = true) String data, @RequestParam(value = "mnr", required = true) Boolean mnr) {
logger.info("/mapmatchstreaming endpoint");
try {
Semaphore semaphore = new Semaphore(1);
ObjectMapper mapper = new ObjectMapper();
StreamingResponseBody responseBody = new StreamingResponseBody() {
@Override
public void writeTo (OutputStream outputStream) throws IOException {
// For each map
DataReader dataReader = new DataReader(data, "2020.06.011");
for(String mapRoot: dataReader.getMapsFolders()) {
dataReader = new DataReader(data, "2020.06.011");
DistributedMapMatcherStreaming distributedMapMatcher = new DistributedMapMatcherStreaming(dataReader.getTraces(), mapRoot, dataReader.getBoundingBox());
distributedMapMatcher.mapMatchBatch(new DistributedMapMatcherResult() {
@Override
public void onCorrectlyMapMatched(MapMatchedTrajectory mapMatchedTrajectory) {
try {
semaphore.acquire();
outputStream.write(mapper.writeValueAsString(mapMatchedTrajectory).getBytes());
outputStream.flush();
}
catch (Exception e) {
e.printStackTrace();
logger.error(String.format("Writing to output stream error: %s", e.getMessage()));
} finally{
semaphore.release();
}
}
});
}
}
};
return new ResponseEntity<StreamingResponseBody>(responseBody, HttpStatus.OK);
}
catch (Exception e) {
logger.error(String.format("Map-matching result ERROR: %s", ExceptionUtils.getStackTrace(e)));
return new ResponseEntity<StreamingResponseBody>(HttpStatus.BAD_REQUEST);
}
}
它工作得很好,但问题是如果多个调用到达这个方法,即使我已经设置了所有这些调用都是并行运行的server.tomcat.threads.max=1
。在非流式传输版本中,每个下一个调用都等待当前调用完成。
是否可以在 Spring 中阻止流式调用?谢谢。
编辑:我暂时通过使用只有 1 个许可证的全局信号量来解决,但我认为这不是理想的解决方案。