并發(fā)的概念
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Java 并發(fā)模型
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JMM - Java Memory Model
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JMM - 重要的理論模型
Java 并發(fā)編碼初體驗
創(chuàng)建標(biāo)記Annotation
package com.accat.concurrency.annoations;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* 用來標(biāo)記【不推薦】的類或者寫法
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.SOURCE)
public @interface NotRecommend {
String value() default "";
}
package com.accat.concurrency.annoations;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* 用來標(biāo)記【線程不安全】的類或者寫法
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.SOURCE)
public @interface NotThreadSafe {
String value() default "";
}
package com.accat.concurrency.annoations;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* 用來標(biāo)記【線程不安全】的類或者寫法
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.SOURCE)
public @interface NotThreadSafe {
String value() default "";
}
package com.accat.concurrency.annoations;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* 用來標(biāo)記【線程安全】的類或者寫法
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.SOURCE)
public @interface ThreadSafe {
String value() default "";
}
測試
package com.accat.concurrency;
import com.mmall.concurrency.annoations.NotThreadSafe;
import lombok.extern.slf4j.Slf4j;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
@Slf4j
@NotThreadSafe
public class ConcurrencyTest {
// 請求總數(shù)
public static int clientTotal = 5000;
// 同時并發(fā)執(zhí)行的線程數(shù)
public static int threadTotal = 200;
public static int count = 0;
public static void main(String[] args) throws Exception {
ExecutorService executorService = Executors.newCachedThreadPool();
final Semaphore semaphore = new Semaphore(threadTotal);
final CountDownLatch countDownLatch = new CountDownLatch(clientTotal);
for (int i = 0; i < clientTotal ; i++) {
executorService.execute(() -> {
try {
semaphore.acquire();
add();
semaphore.release();
} catch (Exception e) {
log.error("exception", e);
}
countDownLatch.countDown();
});
}
countDownLatch.await();
executorService.shutdown();
log.info("count:{}", count);
}
private static void add() {
count++;
}
}
