如何在java中表示无向加权图

有许多不同的方法来表示顶点，边和图。这是一个过于简化的：

定义方向边：

class Edge {

private Vertex to; 
private int weight;

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

Vertex getTo() {
    return to;
}

int getWeight() {
    return weight;
}   

//todo override hashCode()

} 定义一个顶点，以便每个顶点都有一个Edges 的集合到它的：

class Vertex {

private String label;
private Set<Edge> edges; //collection of edges to neighbors 

public Vertex(String pageObject) {
    this.label = pageObject;
    edges = new HashSet<>();
}

String getLabel() {
    return label;
}

boolean addEdge(Edge edge){
    return edges.add(edge);
}

List<Edge> getEdges() {
    return new ArrayList<>(edges);
}

//todo override hashCode()

} 定义一个包含Vertex对象集合的Graph：

class Graph{

private Set<Vertex> vertices; //collection of all verices 

public Graph() {
    vertices = new HashSet<>();
} 

List<Vertex> getVertices() {
    return new ArrayList<>(vertices);
}   

boolean addVertex(Vertex vertex){
    return vertices.add(vertex);
}

} 构建图表：

public static void main(String[] args) {

Graph graph = new Graph();

//construct vertices 
Vertex v1 = new Vertex("1"); 
Vertex v2 = new Vertex("2"); 
Vertex v3 = new Vertex("3");
Vertex v4 = new Vertex("4");
Vertex v5 = new Vertex("5");

v1.addEdge(new Edge(v2, 1)); //connect v1 v2 
v2.addEdge(new Edge(v1, 1));

v2.addEdge(new Edge(v3, 2)); //connect v2 v3
v3.addEdge(new Edge(v2, 2));

v2.addEdge(new Edge(v4, 3)); //connect v2 v4
v4.addEdge(new Edge(v2, 3));

v4.addEdge(new Edge(v5, 1)); //connect v4 v5
v5.addEdge(new Edge(v4, 1));

 graph.addVertex(v1); graph.addVertex(v2); graph.addVertex(v3);
 graph.addVertex(v4); graph.addVertex(v5);  

}