JAVA异常-IllegalMonitorStateException

灰太狼 2022-05-23 09:54 180阅读 0赞

## 前言 ##

记一次小坑，java.lang.IllegalMonitorStateException。

## 解决 ##

看一下官方说Thrown to indicate that a thread has attempted to wait on an object’s monitor or to notify other threads waiting on an object’s monitor without owning the specified monitor.意思就是说用wait和notify的时候没有拥有这个监视器对象，下面是我的代码

package thread;
    
    import java.util.LinkedList;
    import java.util.Random;
    
    public class MyBlockingQueue { 
        private LinkedList<Integer> list = new LinkedList<>();
        final static int MAX_SIZE = 10;
    
        public void in(Integer i) throws ill{
            synchronized (list) {
                while (list.size() == 10) {
                    try {
                        System.out.println("队列已满，阻塞");
                        wait();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
                list.add(i);
                list.notifyAll();
                System.out.println("已读进值此时队列大小为" + list.size());
            }
        }
    
        public void out() {
            synchronized (list) {
                while (list.size() == 0) {
                    try {
                        System.out.println("队列已空，阻塞");
                        wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                list.remove();
                list.notifyAll();
                System.out.println("已删除值此时队列大小为" + list.size());
            }
        }
    
        public static void main(String[] args) {
            MyBlockingQueue queue = new MyBlockingQueue();
    
            for (int i = 0; i < 10; i++) {
                new Thread(new Runnable() {
    
                    @Override
                    public void run() {
                        Random r = new Random();
                        int temp = r.nextInt(100);
                        if (temp > 70) {
                            queue.in(2);
                        } else {
                            queue.out();
                        }
                    }
                }).start();
            }
        }
    }

找了又找，才发现原来是wait方法前面没有加list。解决