异步执行

异步执行通过调用queue()方法实现

Future<String> fs = new CommandHelloWorld("World").queue();

The value can then be retrieved using the Future:

String s = fs.get();

下面的单元测试显示了这一行为

@Test
        public void testAsynchronous1() throws Exception {
            assertEquals("Hello World!", new CommandHelloWorld("World").queue().get());
            assertEquals("Hello Bob!", new CommandHelloWorld("Bob").queue().get());
        }

        @Test
        public void testAsynchronous2() throws Exception {

            Future<String> fWorld = new CommandHelloWorld("World").queue();
            Future<String> fBob = new CommandHelloWorld("Bob").queue();

            assertEquals("Hello World!", fWorld.get());
            assertEquals("Hello Bob!", fBob.get());
        }

下面的代码功能是相同的

String s1 = new CommandHelloWorld("World").execute();
String s2 = new CommandHelloWorld("World").queue().get();