一道面试题，循环按顺序打印ABCD，每个线程只打印一个字母

爱被打了一巴掌 2022-05-14 12:05 142阅读 0赞

import java.util.concurrent.atomic.AtomicInteger;
    
    /** * 一道面试题，循环按顺序打印ABCD，每个线程只打印一个字母 当时未做出来，回来经研究以一下代码实现 * * @author Loong * */
    public class Print { 
        public static void main(String[] args) {
            String[] contents = { "A", "B", "C", "D" };
            AtomicInteger index = new AtomicInteger(0);
    
            for (String content : contents) {
                new Thread(new Printer(index, contents, content)).start();
            }
        }
    }
    
    class Printer implements Runnable { 
        private String[] content = null;
        private AtomicInteger index;
        private String printText;
    
        public Printer(AtomicInteger index, String[] content, String printText) {
            this.content = content;
            this.index = index;
            this.printText = printText;
        }
    
        @Override
        public void run() {
            while (true) {
                synchronized (content) {
                    while (!printText.equals(content[index.intValue()])) {
                        try {
                            content.wait();
                        } catch (InterruptedException e) {
                            throw new RuntimeException(e);
                        }
                    }
                    System.out.println(printText);
                    index.set(index.intValue() + 1);
                    if (index.intValue() >= content.length) {
                        index.set(0);
                    }
                    content.notifyAll();
                }
            }
        }
    
    }