Usage of atomicinteger (counter)

1、 Why use AtomicInteger

• AtomicReference Classes of atomic classes , It is mainly used for efficient program processing in high concurrency environment , To help us simplify synchronization .
• stay Java In language ,++i and i++ Operations are not thread safe , In use , It's inevitable that synchronized keyword . and AtomicInteger Through a thread safe addition and subtraction interface .

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AtomicInteger Introduce

AtomicInteger It's an atomic operation Integer class , Add and subtract in a thread safe way .

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AtomicInteger Use scenarios

AtomicInteger Provide atomic operations for Integer Use , So it is very suitable for high concurrency .

introduce

import java.util.concurrent.atomic.AtomicInteger;

Get and assign

atomicInteger.get(); // Get current value 
atomicInteger.set(0); // set currency 

getAndAdd() Methods and AddAndGet Method

       AtomicInteger atomicInteger = new AtomicInteger(1);
       System.out.println(atomicInteger.get());  --1

       System.out.println(atomicInteger.getAndAdd(10)); --1  Get current value , And add 10
       System.out.println(atomicInteger.get()); --11

       System.out.println(atomicInteger.addAndGet(10)); --21  Get plus 10 After the value of , First plus 10
       System.out.println(atomicInteger.get()); --21

getAndDecrement() and DecrementAndGet() Method

        AtomicInteger atomicInteger = new AtomicInteger(123);
        System.out.println(atomicInteger.get());   --123

        System.out.println(atomicInteger.getAndDecrement()); --123  Get the current value and subtract 
        System.out.println(atomicInteger.get());  --122


        System.out.println(atomicInteger.decrementAndGet()); --121  First self subtraction and then obtain subtraction 1 After the value of 
        System.out.println(atomicInteger.get()); --121