集合转换成数组--打印数组标签：常用,java,LinkedList,String,add,api,linkedList From： https://www.cnblogs.com/1994xiaojian/p/17016968.html
LinkedList<String> linkedList = new LinkedList<>();
linkedList.add("京");
linkedList.add("津");
linkedList.add("黑");
String[] array = linkedList.toArray(new String[linkedList.size()]);
System.out.println(Arrays.toString(array));
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