Java数组转成list，list转数组

下面介绍一下Java中数组和List集合如何互相转换。

数组转成list

01

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

02

String[] userid = {"aa","bb","cc"};List 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。

03

最笨的方法：String[] userid = {"aa","bb","cc"};List userList = new ArrayList(userid.length);for(String uid: userid){userList.add(uid);}

list转数组

01

List strList = new ArrayList();strList.add("aa");strList.add("bb");Object[] objs = strList.toArray();--------------如果要变成String数组，需要强转类型。String[] strs = (String[]) strList.toArray(new String[0]);-----------------也可以指定大小：String[] strs = strList.toArray(new String[strList.size()]);

02

笨方法：List strList = new ArrayList();strList.add("aa");strList.add("bb");String[] strs = new String[strList.size()];