[英]How to work with CompletableFuture with SpringBoot for restful service
I am facing trouble to understand how an async method works in SpringBoot.我在理解 SpringBoot 中异步方法的工作方式时遇到了麻烦。
Consider I am implementing a micro-service to get the Current, In-process or SoldOff Property of a user or All, depending on the query parameter from the user.考虑我正在实现一个微服务来获取用户或所有的 Current、In-process 或 SoldOff 属性,具体取决于来自用户的查询参数。 I am calling two methods which calls sql scripts to give me the answer.我正在调用两种调用 sql 脚本的方法来给我答案。 I want to run those methods Asynchronously as it can take time.我想异步运行这些方法,因为这可能需要时间。
Example:示例:
@Service
public class PropertyService {
public PropertyVO getPropertySummary() {
CompletableFuture<List<Property>> currentProperty = null;
CompletableFuture<List<Property>> soldProperty = null;
CompletableFuture<List<Property>> inProcessProperty = null;
CompletableFuture<List<Property>> allProperty = null;
if(status.equals("ALL")) {
allProperty = propertyDAO.getAllProperty(userId);
}else {
String[] statuses = status.split(",");
for (String st : statuses) {
if (st.equals("CURRENT")) {
currentProperty = propertyDAO.getCurrentProperty(userId);
} else if (st.equals("SOLD")) {
soldProperty = propertyDAO.getSoldProperty(userId);
} else if (st.equals("IN-Process")) {
inProcessProperty = propertyDAO.getInProcessProperty(userId);
}
}
// Do I need this? How would it work when user just needs CURRENT and SOLD. Will it get stuck on IN-PROCESS?
// CompletableFuture.allOf(currentProperty,soldProperty,inProcessProperty).join();
}
// Will it wait here for the above methods to run?
List<Property> allPropertyList = getResult(allProperty);
List<Property> currentPropertyList = getResult(currentProperty);
List<Property> soldPropertyList = getResult(soldProperty);
List<Property> inProcessPropertyList = getResult(inProcessProperty);
..... return Object Property
}
private List<Property> getResult(final CompletableFuture<List<Property>> completableFuture) {
if(completableFuture == null) {
return Lists.newArrayList();
}
return completableFuture.get(30,TIMEUNIT.SEC);
}
}
@Repository
class PropertyRepository {
@Async
@Transactional(readOnly = true)
public CompletableFuture<List<Property>> getCurrentProperty(int userId) {
String query = sqlRetriever.getQueryByKey("SQL_GET_CURRENT_PROPERTY");
return CompletableFuture.completedFuture(getNamedParameterJdbcTemplate().query(query,new PropertyMapper()));
}
@SpringBootApplication
@EnableAsync
public class SpringBootApp {
/**
* The entry point into the application.
*
* @param args
*/
public static void main(String[] args) {
SpringApplication.run(SpringBootApp.class, args).close();
}
@Bean
public Executor asyncExecutor() {
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setCorePoolSize(2);
executor.setMaxPoolSize(2);
executor.setQueueCapacity(500);
executor.setThreadNamePrefix("Property-");
executor.initialize();
return executor;
}
}
Question:问题:
Any Help would be appreciated, I read through all the notes online but I am still confused a little.任何帮助将不胜感激,我在网上通读了所有笔记,但我仍然有点困惑。 I cannot run it locally because i still do not have a full fledged code.我无法在本地运行它,因为我仍然没有完整的代码。
sample Implementation of CompletebleFuture: CompletebleFuture 的示例实现:
private final ExecutorService ioBound;私有最终 ExecutorService ioBound;
CompletableFuture.supplyAsync(() -> this.getCurrentProperty(record), this.ioBound)
.exceptionally(exception -> false)
.thenAccept(input -> {
if (Boolean.FALSE.equals(input)) {
log.error("exception occured:{}", input);
} else
log.info("Success:{}", input);
})
CompletableFuture<String> future1
= CompletableFuture.supplyAsync(() -> "Hello");
CompletableFuture<String> future2
= CompletableFuture.supplyAsync(() -> "Beautiful");
CompletableFuture<String> future3
= CompletableFuture.supplyAsync(() -> "World");
CompletableFuture<Void> combinedFuture
= CompletableFuture.allOf(future1, future2, future3);
// ...
combinedFuture.get();
assertTrue(future1.isDone());
assertTrue(future2.isDone());
assertTrue(future3.isDone());
Please check section 8 - Running Multiple Futures in Parallel here请在此处查看第 8 节 - 并行运行多个期货
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