如何使用FastFoot轻松搞定JAVA的多任务处理(一)

使用FastFoot轻松搞定JAVA的多任务处理

（一）FastFoot简介
（二）下载FastFoot
（三）如何导入FastFoot
（四）FastFoot的调用方法
（五）官网例子
（六）执行结果
（七）结论

（一）FastFoot简介

FastFoot(快脚)是一款处理JAVA多任务的利器，可以非常简单和高效的进行多任务的分解并处理，并在全部任务处理后，对所有任务的结果及进行合并返回，使用者可以当做同步方法来调用，完全不用操作复杂的JAVA线程同时可以达到很高执行效率。

（二）下载FastFoot

你可以通过github来下载 ,这个工具。

（三）如何导入FastFoot

可以两种方式引用FastFoot:

引用jar包方式，在下载工程的
target中已经生成了FastFoot-1.0-SNAPSHOT.jar，可以引用。
直接使用java文件，拷贝在src\main\java\org\lwl\fastfoot目录的FastFoot.java文件到自己的工程即可。FastFoot实现并不复杂，目前只一个文件就搞定了所有的事情。

（四）FastFoot的调用方法

FastFoot目前提供两种调用方法，一种为默认方法自动启动20个线程进行多任务处理。另一种可以通过传递feet参数来控制启动线程的个数。

默认调用方法

    /**
    * Run Task by by default 20 threads，and wait all task completed to get all result。
    *
    * @param taskList task list
    * @param function function for run every task
    * @param <T> task class type
    * @param <R> result class type
    * @return task and result map
    */
   public static <T, R> Map<T, R> runTasks(List<T> taskList, Function<T, R> function){
       return runTasks(taskList, function, 20);
   }

指定feet调用方法

/**
   * Run Task by multi thread，and wait all task completed to get all result。
   *
   * @param taskList task list
   * @param function function for run every task
   * @param feet create thread number when run the tasks
   * @param <T> task class type
   * @param <R> result class type
   * @return task and result map
   */
  public static <T, R> Map<T, R> runTasks(List<T> taskList, Function<T, R> function, int feet)

官网上已经给出了相应的例子，下面简单翻译一下。

（五）官网例子

创建简单的多任务，实际情况可以是数据库，文件操作等

 List<Integer> taskList = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20);

创建函数来执行多任务，这里使用了java8的函数式编程，不会的需要学习一下写法。

 Function<Integer, List<String>> function = count -> {
 List<String> list = new ArrayList<>();
 for (int i = 0; i < count; i++) {
     try {
         // Simulate time-consuming operations
         TimeUnit.MILLISECONDS.sleep(100);
     } catch (InterruptedException e) {
         e.printStackTrace();
     }
     list.add(String.valueOf(i+1));
   }
   return list;
 };

如在不使用FastFoot时，以单线程方式进行处理如下

 long start = System.currentTimeMillis();
 Map<Integer, List<String>> map = new HashMap<>();
 Map<Integer, List<String>> finalMap = map;
 taskList.forEach(task -> {
     finalMap.put(task, function.apply(task));
 });
 System.out.println("Not use FastFoot, all task complete by costing:" + (System.currentTimeMillis() - start)+"ms");
 System.out.println("result:" + map);

使用 FastFoot，feet参数即线程数用5

start = System.currentTimeMillis();
map = FastFoot.runTasks(taskList, function, 5);
System.out.println("Use Fast Foot with 5 threads, all task complete by costing:" + (System.currentTimeMillis() - start)+"ms");
System.out.println("result:" + map);

使用 FastFoot，默认不传foots参数即线程数用20

start = System.currentTimeMillis();
map = FastFoot.runTasks(taskList, function);
System.out.println("Use Fast Foots with 20 threads, All task complete by costing:" + (System.currentTimeMillis() - start)+"ms");
System.out.println("result:" + map);

（六）执行结果

Not use FastFoot, all task complete by costing:22845ms
result:{1=[1], 2=[1, 2], 3=[1, 2, 3], 4=[1, 2, 3, 4], 5=[1, 2, 3, 4, 5], 6=[1, 2, 3, 4, 5, 6], 7=[1, 2, 3, 4, 5, 6, 7], 8=[1, 2, 3, 4, 5, 6, 7, 8], 9=[1, 2, 3, 4, 5, 6, 7, 8, 9], 10=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 11=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 12=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], 13=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13], 14=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14], 15=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], 16=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16], 17=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17], 18=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18], 19=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19], 20=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]}
Use FastFoot with 5 threads, all task complete by costing:5135ms
result:{1=[1], 2=[1, 2], 3=[1, 2, 3], 4=[1, 2, 3, 4], 5=[1, 2, 3, 4, 5], 6=[1, 2, 3, 4, 5, 6], 7=[1, 2, 3, 4, 5, 6, 7], 8=[1, 2, 3, 4, 5, 6, 7, 8], 9=[1, 2, 3, 4, 5, 6, 7, 8, 9], 10=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 11=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 12=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], 13=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13], 14=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14], 15=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], 16=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16], 17=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17], 18=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18], 19=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19], 20=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]}
Use FastFoot with 20 threads, All task complete by costing:2032ms
result:{1=[1], 2=[1, 2], 3=[1, 2, 3], 4=[1, 2, 3, 4], 5=[1, 2, 3, 4, 5], 6=[1, 2, 3, 4, 5, 6], 7=[1, 2, 3, 4, 5, 6, 7], 8=[1, 2, 3, 4, 5, 6, 7, 8], 9=[1, 2, 3, 4, 5, 6, 7, 8, 9], 10=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 11=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 12=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], 13=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13], 14=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14], 15=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], 16=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16], 17=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17], 18=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18], 19=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19], 20=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]}

（七）结论

在使用FastFoot默认线程数20时执行速度最快，相当于单线程时的1/10。FastFoot最佳实践是设定线程数与任务数相等，这样执行的总耗时就几乎等于多任务中的最大单任务耗时。