玩玩Java多线程共享资源

1.实现效果与思路

需要达到的效果

• 一个集合里面有大量的数据，要求用多线程去操作该数据，线程处理完成后将结果返回给主线程

实现思路

• 在java中开启子线程有两种方式

  1.方式一：implements Runnable

  2.方式二：extends Thread

• 由于我们需要资源共享，所以选择了implements Runnable，并且使用线程池进行线程的控制

2.工作线程的实现逻辑

    package com.timmy008;    import java.util.Map;    import java.util.Map.Entry;    /**     * 工作线程     *      * @author Administrator     *     */    public class WorkerThread implements Runnable {        /**         * 任务的集合         */        private volatile Map<String, Work> maps;        /**         * 当前线程执行任务的结果         */        private volatile int result = 0;        private ResultCallback mCallback;        private boolean flag;        public WorkerThread(Map<String, Work> maps) {            super();            this.maps = maps;        }        /**         * 进行的工作         */        private void doWork() {            for (Entry<String, Work> entry : maps.entrySet()) {                synchronized (maps) {                    Work value = entry.getValue();                    if (value != null) {                        if (!value.isRunning()) {                            // TODO 这是执行任务                            System.out.println("当前" + Thread.currentThread().getName() + "正在执行任务" + entry.getKey());                            value.setRunning(true);                            result += value.getWorking();                        }                    }                }            }            if (mCallback != null && !flag) {                flag =true;                mCallback.onResult(result);            }        }        public void setResultCallback(ResultCallback callback) {            this.mCallback = callback;        }        @Override        public void run() {            doWork();        }    }

3.结果的回调

    package com.timmy008;    /**     * 结果的回调     * @author Administrator     *     */    public interface ResultCallback {        /**         * 返回结果         *         * @param result         */        void onResult(int result);    }

4.具体的工作实体

    package com.timmy008;    /**     * 工作的实体     * @author Administrator     *     */    public class Work {        /**         * 是否运行         */        private boolean isRunning;        /**         * 具体工作         */        private int working;        public Work(boolean isRunning, int working) {            super();            this.isRunning = isRunning;            this.working = working;        }        public boolean isRunning() {            return isRunning;        }        public void setRunning(boolean isRunning) {            this.isRunning = isRunning;        }        public int getWorking() {            return working;        }        public void setWorking(int working) {            this.working = working;        }        @Override        public String toString() {            StringBuilder builder = new StringBuilder();            builder.append("Work [isRunning=");            builder.append(isRunning);            builder.append(", working=");            builder.append(working);            builder.append("]");            return builder.toString();        }    }

5.测试类

    package com.timmy008;    import java.util.HashMap;    import java.util.Map;    import java.util.concurrent.ExecutorService;    import java.util.concurrent.Executors;    public class Main {        private static Map<String, Work> maps;        public static void main(String[] args) {            maps = new HashMap<>();            Work work;            for (int i = 0; i < 5000000; i++) {                work = new Work(false, i);                maps.put("当前是任务" + i, work);            }            ExecutorService service = Executors.newCachedThreadPool();            WorkerThread workerThread1 = new WorkerThread(maps);            workerThread1.setResultCallback(new ResultCallback() {                @Override                public void onResult(int result) {                    System.out.println("计算出的结果:" + result);                }            });            for (int i = 0; i < 10; i++) {                service.execute(new Thread(workerThread1));            }            service.shutdown();// 执行完线程池中的线程后尽快退出        }    }

运行结果