今天在编译Java程序时遇到如下问题：
No enclosing instance of type PrintListFromTailToHead is accessible. Must qualify the allocation with an enclosing instance
of type PrintListFromTailToHead (e.g. x.new A() where x is an instance of PrintListFromTailToHead).
源代码为：
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public class PrintListFromTailToHead {public static void main(String[] args) {ListNode one = new ListNode(1);ListNode two = new ListNode(2);ListNode three = new ListNode(3);one.next = two;two.next = three;ArrayList<Integer> result = printListFromTailToHead(one);System.out.println("结果是：" + result);}class ListNode {public int val;public ListNode next;public ListNode() {}public ListNode(int val) {this.val = val;}}public static ArrayList<Integer> printListFromTailToHead(ListNode listNode) {Stack<Integer> stack = new Stack<Integer>();while (listNode != null) {stack.push(listNode.val);listNode = listNode.next;}ArrayList<Integer> arrayList = new ArrayList<Integer>();while (!stack.isEmpty()) {arrayList.add(stack.pop());}return arrayList;} } |
问题解释：
代码中，我的ListNode类是定义在PrintListFromTailToHead类中的内部类。ListNode内部类是动态的内部类，而我的main方法是static静态的。
就好比静态的方法不能调用动态的方法一样。
有两种解决办法：
第一种：
将内部类ListNode定义成静态static的类。
第二种：
将内部类ListNode在PrintListFromTailToHead类外边定义。
两种解决方法：
第一种：
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public class PrintListFromTailToHead {public static void main(String[] args) {ListNode one = new ListNode(1);ListNode two = new ListNode(2);ListNode three = new ListNode(3);one.next = two;two.next = three;ArrayList<Integer> result = printListFromTailToHead(one);System.out.println("结果是：" + result);}static class ListNode {public int val;public ListNode next;public ListNode() {}public ListNode(int val) {this.val = val;}} |
第二种：
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public class PrintListFromTailToHead {public static void main(String[] args) {ListNode one = new ListNode(1);ListNode two = new ListNode(2);ListNode three = new ListNode(3);one.next = two;two.next = three;}public static ArrayList<Integer> printListFromTailToHead(ListNode listNode) {Stack<Integer> stack = new Stack<Integer>();while (listNode != null) {stack.push(listNode.val);listNode = listNode.next;}ArrayList<Integer> arrayList = new ArrayList<Integer>();while (!stack.isEmpty()) {arrayList.add(stack.pop());}return arrayList;}}class ListNode {public int val;public ListNode next;public ListNode() {}public ListNode(int val) {this.val = val;}} |
以上所述是小编给大家介绍的Java解决No enclosing instance of type PrintListFromTailToHead is accessible问题的两种方案，希望对大家有所帮助。
原文链接：http://www.cnblogs.com/lfeng1205/archive/2016/07/24/5700735.html
