Java实现的权重算法（按权重展现广告）

import java.util.ArrayList;import java.util.Collections;import java.util.Comparator;import java.util.LinkedHashMap;import java.util.List;import java.util.Map;public class Test {  /**   * @param args   */  @SuppressWarnings("unchecked")  public static void main(String[] args) {        List<Node> arrNodes = new ArrayList<Node>();    Node n = new Node(10, "测试1");    arrNodes.add(n);    n = new Node(20, "测试2");    arrNodes.add(n);    n = new Node(30, "测试3");    arrNodes.add(n);    n = new Node(40, "测试4");    arrNodes.add(n);        //Collections.sort(arrNodes, new Node());    Map<String, Integer> showMap = null;    int sum = getSum(arrNodes);    int random = 0;    Node kw = null;    for(int k = 0; k < 20; k++) {      showMap = new LinkedHashMap<String, Integer>();      for(int i = 0; i < 100; i++) {        random = getRandom(sum);        kw = getKW(arrNodes, random);        if(showMap.containsKey(kw.kw)) {          showMap.put(kw.kw, showMap.get(kw.kw) + 1);        } else {          showMap.put(kw.kw, 1);        }        //System.out.println(i + " " +random + " " + getKW(arrNodes, random));      }      System.out.print(k + " ");      System.out.println(showMap);    }  }    public static Node getKW(List<Node> nodes, int rd) {    Node ret = null;    int curWt = 0;    for(Node n : nodes){      curWt += n.weight;      if(curWt >= rd) {        ret = n;        break;      }    }    return ret;  }  public static int getSum(List<Node> nodes) {    int sum = 0;    for(Node n : nodes)      sum += n.weight;    return sum;  }  public static int getRandom(int seed) {    return (int)Math.round(Math.random() * seed);  }}class Node implements Comparator{  int weight = 0;  String kw = "";    public Node() {}    public Node(int wt, String kw) {    this.weight = wt;    this.kw = kw;  }  public String toString(){    StringBuilder sbBuilder = new StringBuilder();    sbBuilder.append(" weight=").append(weight);    sbBuilder.append(" kw").append(kw);    return sbBuilder.toString();  }  public int compare(Object o1, Object o2) {    Node n1 = (Node)o1;    Node n2 = (Node)o2;    if(n1.weight > n2.weight)      return 1;    else       return 0;  }}