009.多线程-AtomicInteger

落日映苍穹つ 2021-10-06 15:30 259阅读 0赞

package cn.qbz.thread;
    
    import java.util.concurrent.atomic.AtomicInteger;
    
    public class AtomicTest { 
        public static void main(String[] args) { 
            AtomicInteger count = new AtomicInteger(0);
            //分10个线程，每个线程自增2000次
            for (int i = 0; i < 10; i++) { 
                new Thread(new ThreadTest1(count)).start();
            }
            try { 
                Thread.sleep(1000);
            } catch (InterruptedException e) { 
                e.printStackTrace();
            }
            System.out.println(count.get());
    
        }
    }
    
    class ThreadTest1 implements Runnable { 
        private AtomicInteger integer;
    
        ThreadTest1(AtomicInteger integer) { 
            this.integer = integer;
        }
    
        public void run() { 
            for (int i = 0; i < 2000; i++) { 
                integer.incrementAndGet();
            }
        }
    }

![idea64_2018-11-15_18-32-39.png][]

--------------------

**此时的数值会小于20000**

package cn.qbz.thread;
    
    
    public class AtomicTest { 
    	//静态变量可为多线程共享
        private static Integer count = 0;
    
        public static void main(String[] args) { 
            //分10个线程，每个线程自增2000次
            for (int i = 0; i < 10; i++) { 
                new Thread(new Runnable() { 
                    public void run() { 
                        for (int i = 0; i < 2000; i++) { 
                            count++;
                        }
                    }
                }).start();
            }
            try { 
                Thread.sleep(1000);
            } catch (InterruptedException e) { 
                e.printStackTrace();
            }
            System.out.println(count);
    
        }
    }

--------------------

**如上面一样，使用AtomicInteger**

package cn.qbz.thread;
    
    
    import java.util.concurrent.atomic.AtomicInteger;
    
    public class AtomicTest { 
    
        public static void main(String[] args) { 
            final AtomicInteger count = new AtomicInteger(0);
            //分10个线程，每个线程自增2000次
            for (int i = 0; i < 10; i++) { 
                new Thread(new Runnable() { 
                    public void run() { 
                        for (int i = 0; i < 2000; i++) { 
                            count.incrementAndGet();
                        }
                    }
                }).start();
            }
            try { 
                Thread.sleep(1000);
            } catch (InterruptedException e) { 
                e.printStackTrace();
            }
            System.out.println(count.get());
    
        }
    }

--------------------

**其他的Atomic类与此类似**

[idea64_2018-11-15_18-32-39.png]: http://upyun.qubianzhong.cn/picture/idea64_2018-11-15_18-32-39.png