java set转list，数组与list的转换

读zookeeper的源码(zookeeper.java)时发现的，平时没有怎么注意：

private final ZKWatchManager watchManager;

List<String> getDataWatches() {
synchronized(watchManager.dataWatches) {
List<String> rc = new ArrayList<String>(watchManager.dataWatches.keySet());
return rc;
}
}
List<String> getExistWatches() {
synchronized(watchManager.existWatches) {
List<String> rc =  new ArrayList<String>(watchManager.existWatches.keySet());
return rc;
}
}
List<String> getChildWatches() {
synchronized(watchManager.childWatches) {
List<String> rc = new ArrayList<String>(watchManager.childWatches.keySet());
return rc;
}
}

另数组与list的转换：

数组-->list

String[] userid = {"aa","bb","cc"};
List<String> userList = new ArrayList<String>();
Collections.addAll(userList, userid);

数组-->list

String[] userid = {"aa","bb","cc"};
List<String> userList = Arrays.asList(userid);
另：Arrays.asList()返回一个受指定数组支持的固定大小的列表。所以不能做Add、Remove等操作。
List list = new ArrayList(Arrays.asList(userid));这样操作就可以了。

list-->数组

List<String> strList = new ArrayList<String>();
strList.add("aa");
strList.add("bb");
Object[] objs = strList.toArray();

参考文献：

【1】http://jingyan.baidu.com/article/86f4a73e607f2937d7526972.html

【2】https://github.com/apache/zookeeper