Java8 CompletableFuture concurrence example 2019-03-27 06:41
It is very convenient to use CompleteFuture to implement concurrency in java8. I will show you how to use it in this page. Let's say you need to query someone's information(address, company name, family). Every query need 300ms. If you request the information one by one, you will need about 1 second. If you use the CompleteFuture concurrent request, it only takes 300 milliseconds.
public class CompletableFutureConcurrenceClient {
private static final Executor executor =
Executors.newFixedThreadPool(600, r -> {
Thread t = new Thread(r);
t.setDaemon(true);
return t;
});
public static void main(String[] args) throws ExecutionException, InterruptedException {
long beginTime = System.currentTimeMillis();
String userName = "henry";
CompletableFuture<String> addressFuture = CompletableFuture.supplyAsync(() -> getAddress(userName));
CompletableFuture<String> companyNameFuture = CompletableFuture.supplyAsync(() -> getCompanyName(userName));
CompletableFuture<String> familyFuture = CompletableFuture.supplyAsync(() -> getFamilyInfo(userName));
CompletableFuture<String> allInfoFuture = CompletableFuture.allOf(addressFuture, companyNameFuture, familyFuture)
.thenApply(i -> {
String address = addressFuture.join();
String companyName = companyNameFuture.join();
String familyInfo = familyFuture.join();
return "userId:\t" + userName + " \r\n" + address + "\r\n" + companyName + "\r\n" + familyInfo;
});
String allInfo = allInfoFuture.get();
System.out.println(allInfo + "\r\ntime cost:" + (System.currentTimeMillis() - beginTime));
}
private static String getCompanyName(String userName) {
try {
Thread.sleep(300);
} catch (InterruptedException e) {
e.printStackTrace();
}
return userName + " company: \t my_company";
}
private static String getAddress(String userName) {
try {
Thread.sleep(300);
} catch (InterruptedException e) {
e.printStackTrace();
}
return userName + " address: \t beijing";
}
private static String getFamilyInfo(String userName) {
try {
Thread.sleep(300);
} catch (InterruptedException e) {
e.printStackTrace();
}
return userName + " family: \t wife and son";
}
}
The output is here
userId: henry
henry address: beijing
henry company: my_company
henry family: wife and son
time cost:305
EOF