java.util.ConcurrentModificationException

来源：互联网发布：sumts是什么网络类型编辑：程序博客网时间：2024/06/01 19:40

遍历List的时候不能删除元素。代码如下：

private final static Map<String, List<Map<String, String>>> newServerInfo                = new HashMap<String, List<Map<String, String>>>();private final static Map<String, Long> newServerInfoDate = new HashMap<String, Long>();                 for (Entry<String, Long> entry : newServerInfoDate.entrySet()) {String key = entry.getKey();long date = entry.getValue();System.out.println(System.currentTimeMillis() - date + "---"+ outTimeNum * 1000);if (System.currentTimeMillis() - date >= outTimeNum * 1000) {      newServerInfo.remove(key);    newServerInfoDate.remove(key);    if (newServerInfoDate.size() == 0)break;}}

for循环遍历时不可删除，修改如下：

List<String> removeKey = new ArrayList<String>();for (Entry<String, Long> entry : newServerInfoDate.entrySet()) {String key = entry.getKey();long date = entry.getValue();System.out.println(System.currentTimeMillis() - date + "---"+ outTimeNum * 1000);if (System.currentTimeMillis() - date >= outTimeNum * 1000) {    removeKey.add(key);    if (newServerInfoDate.size() == 0)        break;}} for (String key : removeKey) {newServerInfo.remove(key);newServerInfoDate.remove(key);}

遍历时，把需要删除的元素的key保存下来，遍历完成之后再删除。

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