🏷 HTTP
5 patterns
Topic: HTTP
All Java patterns related to HTTP — java.evolved
Concurrency
Concurrent HTTP with virtual threads
Old
ExecutorService pool =
Executors.newFixedThreadPool(10);
List<Future<String>> futures =
urls.stream()
.map(u -> pool.submit(
() -> fetchUrl(u)))
.toList();
// manual shutdown, blocking get()
Modern
try (var exec = Executors
.newVirtualThreadPerTaskExecutor()) {
var results = urls.stream()
.map(u -> exec.submit(
() -> client.send(req(u),
ofString()).body()))
.toList().stream()
.map(Future::join).toList();
}
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JDK 21+
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I/O
Modern HTTP client
Old
URL url = new URL("https://api.com/data");
HttpURLConnection con =
(HttpURLConnection) url.openConnection();
con.setRequestMethod("GET");
BufferedReader in = new BufferedReader(
new InputStreamReader(con.getInputStream()));
// read lines, close streams...
Modern
var client = HttpClient.newHttpClient();
var request = HttpRequest.newBuilder()
.uri(URI.create("https://api.com/data"))
.build();
var response = client.send(
request, BodyHandlers.ofString());
String body = response.body();
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JDK 11+
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I/O
WebSocket clients with java.net.http
Old
WebSocketClient client =
new WebSocketClient(serverUri) {
@Override
public void onMessage(String message) {
handle(message);
}
};
client.connect();
Modern
HttpClient.newHttpClient()
.newWebSocketBuilder()
.buildAsync(serverUri,
new WebSocket.Listener() {
@Override
public CompletionStage<?> onText(
WebSocket socket,
CharSequence data,
boolean last) {
handle(data.toString());
return WebSocket.Listener.super
.onText(socket, data, last);
}
});
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JDK 11+
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I/O
Deprecated URL constructors to URI
Old
URL endpoint =
new URL("https://example.com/api?q=java");
Modern
URI endpointUri =
URI.create("https://example.com/api?q=java");
URL endpoint = endpointUri.toURL();
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JDK 20+
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Tooling
Built-in HTTP server
Old
// Install and configure a web server
// (Apache, Nginx, or embedded Jetty)
// Or write boilerplate with com.sun.net.httpserver
HttpServer server = HttpServer.create(
new InetSocketAddress(8080), 0);
server.createContext("/", exchange -> { ... });
server.start();
Modern
// Terminal: serve current directory
$ jwebserver
// Or use the API (JDK 18+)
var server = SimpleFileServer.createFileServer(
new InetSocketAddress(8080),
Path.of("."),
OutputLevel.VERBOSE);
server.start();
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JDK 18+
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