小编ita*_*shi的帖子

我正在尝试使用方法上的同步与原子变量(java.util.concurrent.atomic包)进行Java多线程.

以下是课程:

// Interface ICounter.java
        public interface ICounter {
            public void increment();
            public void decrement();
            public int value();
        }

// Class Counter.java
    public class Counter implements ICounter {
        private int c = 0;

        @Override
        public void increment() {
            c++;
        }

        @Override
        public void decrement() {
            c--;
        }

        @Override
        public int value() {
            return c;
        }
    }

// Class AtomicCounter.java
    import java.util.concurrent.atomic.AtomicInteger;

    public class AtomicCounter implements ICounter {
        private AtomicInteger c = new AtomicInteger(0);

        @Override
        public void increment() {
            c.incrementAndGet();
        } …

哪一个性能更快？

SELECT field1, field2, field3, field4
FROM MyTable
WHERE field5 LIKE '%AL'

与

SELECT field1, field2, field3, field4
FROM MyTable
WHERE field5 IN ('AAL', 'IAL')

或者它没有任何区别？