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A.啓動類:
@EnableAsync 註解主要是爲了掃描範圍包下的所有 @Async註解
package springboot_async;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@EnableAsync
public class App {
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
}
B.使用異步回調:
在controller中無限循環判斷異步方法是否執行完成。
在service的方法中返回Future值。
controller:
package springboot_async.async_test;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class TestController {
@Autowired
private MyService myService;
@RequestMapping("/test")
public String getInedx() throws InterruptedException, ExecutionException {
System.out.println("開始訪問");
long l1 = System.currentTimeMillis();
Future<String> r1 = myService.JobOne();
Future<String> r2 = myService.JobTwo();
Future<String> r3 = myService.JobThree();
while(true) {//死循環,每隔2000ms執行一次,判斷一下這三個異步調用的方法是否全都執行完了。
if(r1.isDone() && r2.isDone() && r3.isDone()) {//使用Future的isDone()方法返回該方法是否執行完成
//如果異步方法全部執行完,跳出循環
break;
}
Thread.sleep(2000);//每隔2000毫秒判斷一次
}
long l2 = System.currentTimeMillis();//跳出while循環時說明此時三個異步調用的方法都執行完成了,此時得到當前時間
String result = r1.get();
System.out.println("結束訪問,用時"+(l2-l1));
System.out.println("使用get方法獲得的返回內容:"+result);
return "finished";
}
}
C.service :
package springboot_async.async_test;
import java.util.concurrent.Future;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Service;
@Service
public class MyService {
@Async
public Future<String> JobOne() throws InterruptedException {
System.out.println("開始執行任務一");
long l1 = System.currentTimeMillis();
Thread.sleep(2000);
long l2 = System.currentTimeMillis();
System.out.println("任務一用時"+(l2-l1));
return new AsyncResult<String>("任務一完成");//可以使用try,catch定義在正常完成時返回一個success信息,出現異常時返回error信息。
}
@Async
public Future<String> JobTwo() throws InterruptedException {
System.out.println("開始執行任務二");
long l1 = System.currentTimeMillis();
Thread.sleep(2000);
long l2 = System.currentTimeMillis();
System.out.println("任務二用時"+(l2-l1));
return new AsyncResult<String>("任務二完成");
}
@Async
public Future<String> JobThree() throws InterruptedException {
System.out.println("開始執行任務三");
long l1 = System.currentTimeMillis();
Thread.sleep(2000);
long l2 = System.currentTimeMillis();
System.out.println("任務三用時"+(l2-l1));
return new AsyncResult<String>("任務三完成");
}
}