在Java中对列表进行排序的最快方法

Question

我在Java中有以下代码:

   public  class ServerInfo {
    int serverId;
    int serverDataRate;
    public ServerInfo(int serverId, int serverDataRate) {
        this.serverId = serverId;
        this.serverDataRate = serverDataRate;
    }
    public int getServerId() {
        return serverId;
    }
    public double getServerDataRate() {
        return serverDataRate;
    }
       public String toString(){
            return serverId + ":" + serverDataRate;
        }
    }    

    public class ServerInfoComparator implements Comparator<ServerInfo> {

    @Override
    public int compare(ServerInfo o1, ServerInfo o2) {
          double datarate1=o1.getServerDataRate();
          double datarate2=o2.getServerDataRate();

          if(datarate1>datarate2)
              return -1;
          else if(datarate1<datarate2)
              return +1;
          else
              return 0;
    }           
}

   public class Sample {
    List<ServerInfo> listOfServers= new ArrayList<ServerInfo>();

    public void insertIntoList(){

        listOfServers.add( new ServerInfo(0,256));
        listOfServers.add( new ServerInfo(1,270));
        listOfServers.add( new ServerInfo(2,256));
        listOfServers.add( new ServerInfo(3,290));
        listOfServers.add( new ServerInfo(4,300));
        listOfServers.add( new ServerInfo(5,300));
        listOfServers.add( new ServerInfo(6,256));
        listOfServers.add( new ServerInfo(7,265));
        listOfServers.add( new ServerInfo(8,289));
        listOfServers.add( new ServerInfo(9,310));  
    }

    public static void main( String[] args){
        Sample s = new Sample();
        s.insertIntoList();
        ServerInfoComparator com  = new ServerInfoComparator();
        Collections.sort(s.listOfServers,com);

        for( ServerInfo server: s.listOfServers){
            System.out.println(server);
        }           
    }
}

我使用上面的代码基于serverDataRate按降序对元素进行排序.假设我在列表中有100个元素的更大样本集,并且代码必须每5-10秒执行一次,那么样本集非常小.这是对列表进行排序的最快方法还是有一种我不知道的更快的方法？

Answer 1

我改变了你的考试

private final List<ServerInfo> listOfServers = new ArrayList<ServerInfo>();

public void insertIntoList() {
    for (int i = 0; i < 1000000; i++)
        listOfServers.add(new ServerInfo(i, (int) (200 + Math.random() * 200)));
}

public static void main(String[] args) {
    MyApp s = new MyApp();
    s.insertIntoList();
    ServerInfoComparator com = new ServerInfoComparator();
    long start = System.nanoTime();
    Collections.sort(s.listOfServers, com);
    long time = System.nanoTime() - start;
    System.out.printf("Sorting %,d took %.3f seconds%n", s.listOfServers.size(), time/1e9);

    for (ServerInfo server : s.listOfServers) {
//    System.out.println(server);
    }
}

它打印出来

Sorting 1,000,000 took 0.438 seconds

那要快一点;)

顺便说一句:我改变了double字段int.