编写java代码，有向图，节点为node 边为edge ,并求该图形的两点之间最短路径及长度。如果不可达则写成-1

下面是使用Java语言实现有向图最短路径算法的示例代码。该算法基于Dijkstra算法实现。

import java.util.*;

public class ShortestPath {
    private final int V; // 节点数
    private List<Edge>[] adj; // 邻接表

    private static class Edge {
        int to;
        int weight;

        Edge(int to, int weight) {
            this.to = to;
            this.weight = weight;
        }
    }

    public ShortestPath(int V) {
        this.V = V;
        adj = new List[V];
        for (int i = 0; i < V; i++) {
            adj[i] = new ArrayList<>();
        }
    }

    public void addEdge(int from, int to, int weight) {
        adj[from].add(new Edge(to, weight));
    }

    public int[] dijkstra(int s) {
        int[] dist = new int[V];
        Arrays.fill(dist, Integer.MAX_VALUE);
        dist[s] = 0;

        PriorityQueue<Node> pq = new PriorityQueue<>();
        pq.offer(new Node(s, 0));

        while (!pq.isEmpty()) {
            Node node = pq.poll();
            int u = node.u;
            int d = node.dist;

            if (d != dist[u]) {
                continue;
            }

            for (Edge e : adj[u]) {
                int v = e.to;
                int w = e.weight;

                if (dist[u] + w < dist[v]) {
                    dist[v] = dist[u] + w;
                    pq.offer(new Node(v, dist[v]));
                }
            }
        }

        return dist;
    }

    private static class Node implements Comparable<Node> {
        int u;
        int dist;

        Node(int u, int dist) {
            this.u = u;
            this.dist = dist;
        }

        @Override
        public int compareTo(Node o) {
            return Integer.compare(dist, o.dist);
        }
    }

    public static void main(String[] args) {
        ShortestPath graph = new ShortestPath(5);

        graph.addEdge(0, 1, 10);
        graph.addEdge(0, 4, 5);
        graph.addEdge(1, 2, 1);
        graph.addEdge(1, 4, 2);
        graph.addEdge(2, 3, 4);
        graph.addEdge(3, 0, 7);
        graph.addEdge(3, 2, 6);
        graph.addEdge(4, 1, 3);
        graph.addEdge(4, 2, 9);
        graph.addEdge(4, 3, 2);

        int[] dist = graph.dijkstra(0);

        System.out.println("Shortest path from 0 to 3: " + dist[3]);
        System.out.println("Shortest path from 0 to 4: " + dist[4]);
        System.out.println("Shortest path from 2 to 0: " + dist[2]);
    }
}

在上述代码中，`ShortestPath`类表示有向图，节点数为`V`。`addEdge`方法用于向图中添加一条从节点`from`到节点`to`，权重为`weight`的有向边。`dijkstra`方法计算从起点`s`到所有其他节点的最短路径，并返回一个包含所有最短路径的数组。其中，`Node`类表示一个节点及其到起点的距离，用于