无法在java泛型中将列表转换为列表错误
发布时间:2020-12-15 00:45:12 所属栏目:Java 来源:网络整理
导读:以下是我的简化图表实现 import java.util.ArrayList;import java.util.List;public class TreeNodeE extends ComparableE { private E data; private ListTreeNodeE children; public TreeNode(E value) { data = value; children = new ArrayList(); } pub
以下是我的简化图表实现
import java.util.ArrayList; import java.util.List; public class TreeNode<E extends Comparable<E>> { private E data; private List<TreeNode<E>> children; public TreeNode(E value) { data = value; children = new ArrayList<>(); } public E getData() { return data; } public void setData(E data) { this.data = data; } public List<TreeNode<E>> getChildren() { return children; } public void setChildren(List<TreeNode<E>> children) { this.children = children; } } 我正在编写代码来查找有向图中是否连接了2个节点.我收到编译错误 public static boolean findIfPathExists(TreeNode<? extends Comparable<?>> start,TreeNode<? extends Comparable<?>> end) { Set<TreeNode<? extends Comparable<?>>> visitedNodes = new HashSet<TreeNode<? extends Comparable<?>>>(); return findIfPathExists(start,end,visitedNodes); } private static boolean findIfPathExists(TreeNode<? extends Comparable<?>> start,TreeNode<? extends Comparable<?>> end,Set<TreeNode<? extends Comparable<?>>> visitedNodes) { if(start == end) return true; visitedNodes.add(start); List<TreeNode<? extends Comparable<?>>> children = start.getChildren(); for (TreeNode<? extends Comparable<?>> child : children) { if(visitedNodes.contains(child)) continue; if(findIfPathExists(child,visitedNodes)) return true; } return false; } 我在行start.getchildren收到错误 Type mismatch: cannot convert from List<TreeNode<capture #11 -of? extends Comparable<?>>> to List<TreeNode<? extends Comparable<?>>> 解决方法
在方法签名中添加一个类型变量:
public static <T extends Comparable<T>> boolean findIfPathExists( TreeNode<T> start,TreeNode<T> end) { private static <T extends Comparable<T>> boolean findIfPathExists( TreeNode<T> start,TreeNode<T> end,Set<TreeNode<T>> visitedNodes) { 然后在你现在的任何地方使用T?扩展Comparable<?>. (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |