java高并发写入问题

Posted 2021-03-03 酷酷的狐狸

List<String> list = new ArrayList<>();

使用ArrayList对数据进行赋值，会出现不同线程争抢同一资源造成写入失败问题，会抛出异常“ConcurrentModificationException”

List<String> list = new Vector<>();

List<String> list = Collections.synchronizedList(new ArrayList<>());

List<String> list = new CopyOnWriteArrayList();

#CopyOnWriteArrayList代表在写入数据时，源码执行如下

/**
     * Appends the specified element to the end of this list.
     *
     * @param e element to be appended to this list
     * @return {@code true} (as specified by {@link Collection#add})
     */
    public boolean add(E e) {
        final ReentrantLock lock = this.lock;
        lock.lock();
        try {
            Object[] elements = getArray();
            int len = elements.length;
            Object[] newElements = Arrays.copyOf(elements, len + 1);
            newElements[len] = e;
            setArray(newElements);
            return true;
        } finally {
            lock.unlock();
        }
    }