以此图为例：
package com.datastruct;
import java.util.Scanner;
public class TestKruskal {
private static class Edge{
public Edge(int begin,int end,int weight){
this.begin = begin;
this.end = end;
this.weight = weight;
}
int begin;
int end;
int weight;
public String toString() {
return "("+begin+", "+end+") -> "+weight;
}
}
private static class Mgraph{
final int MAXEDGE = ; //最大边数
final int MAXVEX = ; //最大顶点数
int numEdges;
int numVertexes;
String vexs[] = new String[MAXVEX]; //顶点数组
Edge edges[] = new Edge[MAXEDGE]; //边集数组
}
public static void CreateMGraph(Mgraph g){
int i;
Scanner scanner = new Scanner(System.in);
System.out.println("输入 顶点数 和边数 ");
g.numVertexes = scanner.nextInt();
g.numEdges = scanner.nextInt();
System.out.println("输入全部顶点：");
for(i=;i<g.numVertexes;i++){
g.vexs[i] = scanner.next();
}
for(i=;i<g.numEdges;i++){
System.out.println("输入边 begin end weight ");
int begin = scanner.nextInt();
int end = scanner.nextInt();
int weight = scanner.nextInt();
g.edges[i] = new Edge(begin,end,weight);
}
}
public static void print(Mgraph g){
int i;
System.out.println("所有顶点：");
for(i=;i<g.numVertexes;i++){
System.out.print(" "+g.vexs[i]);
}
System.out.println("\n所有边：");
for(i=;i<g.numEdges;i++){
System.out.println(g.edges[i].toString());
}
}
public static int Find(int parent[], int f){
while(parent[f] > ){
f = parent[f];
}
return f;
}
public static void sortByWeight(Mgraph g){
Edge temp;
int i,j;
boolean flag = true;
for(i=;i<g.numEdges- && flag;i++){
flag = false;
for(j=g.numEdges-;j>=i;j--){
if(g.edges[j].weight > g.edges[j+].weight){
temp= g.edges[j];
g.edges[j] = g.edges[j+];
g.edges[j+] = temp;
flag = true;
}
}
}
}
public static void MiniSpanTree_Kruskal(Mgraph g){
sortByWeight(g);//先根据权值从小到大排序
int i,j,n,m;
Edge edge[] = g.edges;
int parent[] = new int[g.MAXVEX];
for(i=;i<g.numVertexes;i++){
parent[i] = ;
}
System.out.println("最小生成树：");
for(i=;i<g.numEdges;i++){
n = Find(parent,edge[i].begin);
m = Find(parent,edge[i].end);
if(n != m){
parent[n] = m;
System.out.println(edge[i].toString());
}
}
}
public static void main(String[] args) {
Mgraph g = new Mgraph();
CreateMGraph(g); // 创建图，边集数组形式
print(g); //打印图的基本信息
MiniSpanTree_Kruskal(g); //找到最小生成树
}
}