@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public class User {

    private long id;
    private String username;
    private String password;
    private long timestamp;
}

Map<String, String> config = Configuration.initConfig("commons.xml");

@Test
public void sendData() throws InterruptedException {
    int cnt = 0;

    while (cnt < 200){
        User user = new User();
        user.setId(cnt);
        user.setUsername("username" + new Random().nextInt((cnt % 5) + 2));
        user.setPassword("password" + cnt);
        user.setTimestamp(System.currentTimeMillis());
        Future<RecordMetadata> future = KafkaUtil.sendDataToKafka(config.get("kafka-topic"), String.valueOf(cnt), JSON.toJSONString(user));
        while (!future.isDone()){
            Thread.sleep(100);
        }
        try {
            RecordMetadata recordMetadata = future.get();
            System.out.println(recordMetadata.offset());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
        System.out.println("發(fā)送消息：" + cnt + "******" + user.toString());
        cnt = cnt + 1;
    }
}

Map<String, String> config = Configuration.initConfig("commons.xml");

Properties kafkaProps = new Properties();
kafkaProps.setProperty("zookeeper.connect", config.get("kafka-zookeeper"));
kafkaProps.setProperty("bootstrap.servers", config.get("kafka-ipport"));
kafkaProps.setProperty("group.id", config.get("kafka-groupid"));

StreamExecutionEnvironment senv = StreamExecutionEnvironment.getExecutionEnvironment();

senv.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);

/** The time characteristic that is used if none other is set. */
    private static final TimeCharacteristic DEFAULT_TIME_CHARACTERISTIC = TimeCharacteristic.ProcessingTime;

senv.addSource(
        new FlinkKafkaConsumer010<>(
                config.get("kafka-topic"),
                new SimpleStringSchema(),
                kafkaProps
        )
).map(x ->{
    return JSON.parseObject(x, User.class);
}).assignTimestampsAndWatermarks(new BoundedOutOfOrdernessTimestampExtractor<User>(Time.milliseconds(1000)) {
    @Override
    public long extractTimestamp(User element) {
        return element.getTimestamp();
    }
})

.keyBy("username")
.timeWindow(Time.seconds(10), Time.seconds(5))
.aggregate(new CountAgg(), new WindowResultFunction())

public class CountAgg implements AggregateFunction<User, Long, Long>{
    @Override
    public Long createAccumulator() {
        return 0L;
    }

    @Override
    public Long add(User value, Long accumulator) {
        return accumulator + 1;
    }

    @Override
    public Long getResult(Long accumulator) {
        return accumulator;
    }

    @Override
    public Long merge(Long a, Long b) {
        return a + b;
    }
}

private static class WindowResultFunction implements WindowFunction<Long, UserViewCount, Tuple, TimeWindow> {

    @Override
    public void apply(Tuple key, TimeWindow window, Iterable<Long> input, Collector<UserViewCount> out) throws Exception {
        Long count = input.iterator().next();
        out.collect(new UserViewCount(((Tuple1<String>)key).f0, window.getEnd(), count));
    }
}

@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public static class UserViewCount {
    private String userName;
    private long windowEnd;
    private long viewCount;

}

.keyBy("windowEnd")
.process(new TopNHotUsers(3))
.print();

private static class TopNHotUsers extends KeyedProcessFunction<Tuple, UserViewCount, String> {

    private int topSize;
    private ListState<UserViewCount> userViewCountListState;

    public TopNHotUsers(int topSize) {
        this.topSize = topSize;
    }

    @Override
    public void onTimer(long timestamp, OnTimerContext ctx, Collector<String> out) throws Exception {
        super.onTimer(timestamp, ctx, out);
        List<UserViewCount> userViewCounts = new ArrayList<>();
        for(UserViewCount userViewCount : userViewCountListState.get()) {
            userViewCounts.add(userViewCount);
        }

        userViewCountListState.clear();

        userViewCounts.sort(new Comparator<UserViewCount>() {
            @Override
            public int compare(UserViewCount o1, UserViewCount o2) {
                return (int)(o2.viewCount - o1.viewCount);
            }
        });

        // 將排名信息格式化成 String, 便于打印
        StringBuilder result = new StringBuilder();
        result.append("====================================\n");
        result.append("時(shí)間: ").append(new Timestamp(timestamp-1)).append("\n");
        for (int i = 0; i < topSize; i++) {
            UserViewCount currentItem = userViewCounts.get(i);
            // No1:  商品ID=12224  瀏覽量=2413
            result.append("No").append(i).append(":")
                    .append("  用戶名=").append(currentItem.userName)
                    .append("  瀏覽量=").append(currentItem.viewCount)
                    .append("\n");
        }
        result.append("====================================\n\n");

        Thread.sleep(1000);

        out.collect(result.toString());

    }

    @Override
    public void open(org.apache.flink.configuration.Configuration parameters) throws Exception {
        super.open(parameters);
        ListStateDescriptor<UserViewCount> userViewCountListStateDescriptor = new ListStateDescriptor<>(
                "user-state",
                UserViewCount.class
        );
        userViewCountListState = getRuntimeContext().getListState(userViewCountListStateDescriptor);

    }

    @Override
    public void processElement(UserViewCount value, Context ctx, Collector<String> out) throws Exception {
        userViewCountListState.add(value);
        ctx.timerService().registerEventTimeTimer(value.windowEnd + 1000);
    }
}