public class Graphtest {      public static void main(String[] args) {             GraphNode n1 = new GraphNode(1);              GraphNode n2 = new GraphNode(2);              GraphNode n3 = new GraphNode(3);              GraphNode n4 = new GraphNode(4);              GraphNode n5 = new GraphNode(5);               n1.neighbors = new GraphNode[]{n2,n3,n5};             n2.neighbors = new GraphNode[]{n1,n4};             n3.neighbors = new GraphNode[]{n1,n4,n5};             n4.neighbors = new GraphNode[]{n2,n3,n5};             n5.neighbors = new GraphNode[]{n1,n3,n4};              breathFirstSeArch(n1, 5);     }      public static void breathFirstSearch(GraphNode root, int x){             if(root.val == x)                     System.out.PRintln("find in root");              Queue queue = new Queue();             root.visITed = true;             queue.enqueue(root);              while(queue.first != null){                     GraphNode c = (GraphNode) queue.dequeue();                     for(GraphNode n: c.neighbors){                              if(!n.visited){                                     System.out.print(n + " ");                                     n.visited = true;                                     if(n.val == x)                                             System.out.println("Find "+n);                                     queue.enqueue(n);                             }                     }             }     } 

}

    value: 2 value: 3 value: 5 Find value: 5value: 4  

代码出处：http://codecloud.net/top-10-algorithms-for-coding-interview-447.html