java / expert
Snippet
Asynchronous Request Processing using DeferredResult
DeferredResult allows freeing up servlet threads while waiting for a background task to complete. This improves scalability for long-running I/O operations by avoiding thread starvation.
snippet.java
java
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@GetMapping("/process")public DeferredResult<ResponseEntity<String>> processAsync() {DeferredResult<ResponseEntity<String>> result = new DeferredResult<>(10000L);CompletableFuture.supplyAsync(() -> longRunningTask()).thenAccept(res -> result.setResult(ResponseEntity.ok(res))).exceptionally(ex -> {result.setErrorResult(ResponseEntity.status(500).body("Failed"));return null;});return result;}
spring
Breakdown
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new DeferredResult<>(10000L)
Creates a result holder with a specific timeout in milliseconds.
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result.setResult(...)
The method that actually sends the final response to the client once the background work is done.