使用了1.9版本的Flink模板来创建项目的。
根据本课学习的内容，运行代码如下：

    public static void main(String[] args) throws Exception{

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        DataSet<String> input = env.readTextFile("file:///Users/jeff/projects/study/flink-train-java/test.txt");
        input.print();
        input.flatMap(new FlatMapFunction<String, Tuple2<String, Integer>>() {
            @Override
            public void flatMap(String s, Collector<Tuple2<String, Integer>> collector) throws Exception {
                String[] tokens = s.toLowerCase().split(" ");
                for (String token: tokens){
                    if (token.length() > 0) {
                        collector.collect(new Tuple2<String, Integer>(token, 1));
                    }

                }
            }
        }).groupBy(0).sum(1).print();
        env.execute("Flink Batch Java API Skeleton");

    }

执行该Main函数时，并没有输出想要的结果，并且程序不会自动停止，而是处于一个运行着的状态。
翻了一下日志，有报一个错：
00:42:34,972 INFO org.apache.flink.runtime.executiongraph.ExecutionGraph - DataSource (at main(BatchWCJavaApp.java:12) (org.apache.flink.api.java.io.TextInputFormat)) (1/8) (98a5cbecb493ed76e173902afdfaad42) switched from CREATED to SCHEDULED.
00:42:34,980 INFO org.apache.flink.runtime.jobmaster.slotpool.SlotPoolImpl - Cannot serve slot request, no ResourceManager connected. Adding as pending request [SlotRequestId{858aa7d798c6f34199c63394476feacd}]

如何解决这个问題？