[移动开发]Flink State示例

Flink State示例

// 流1 要先按照id分组，再设置水印和事件时间，因为后面注册的定时器是基于事件时间的
DataStreamSource<Order> sourceStream1 = env.addSource(consumer);
KeyedStream<Order, String> stream1 = sourceStream1.assignTimestampsAndWatermarks(new BoundedOutOfOrdernessTimestampExtractor<Order>(Time.seconds(5)) {
            @Override
            public long extractTimestamp(Order element) {
				// 这里从element中获取事件时间
                return Order.getTime;
            }
        }).keyBy(Order::getOrderId);
// 流2 要先按照id分组，再设置水印和事件时间，因为后面注册的定时器是基于事件时间的
DataStreamSource<Order> sourceStream2 = env.addSource(consumer);
KeyedStream<Order, String> stream2 = sourceStream1.assignTimestampsAndWatermarks(new BoundedOutOfOrdernessTimestampExtractor<Order>(Time.seconds(5)) {
            @Override
            public long extractTimestamp(Order element) {
				// 这里从element中获取事件时间
                return Order.getTime;
            }
        }).keyBy(Order::getOrderId);
// 定义两个侧切流的outputTag
OutputTag<Order> outputTag1 = new OutputTag<>("stream1");
OutputTag<Order> outputTag2 = new OutputTag<>("stream2");

做双流connect
 
stream1.connect(stream2).process(new CoProcessFunction<Order, Order, Tuple2<Order, Order>>() {
 
	// 流1的状态
	ValueState<Order> state1;
	// 流2的状态
	ValueState<Order> state2;
	
	// 定义一个用于删除定时器的状态
	ValueState<Long> timeState;
	
	@Override
	public void open(Configuration parameters) throws Exception {
		super.open(parameters);
		// 初始化状态
		state1 = getRuntimeContext().getState(new ValueStateDescriptor<>("state1", Order.class));
		state2 = getRuntimeContext().getState(new ValueStateDescriptor<>("state2", Order.class));
		timeState = getRuntimeContext().getState(new ValueStateDescriptor<>("timeState", Long.class));
	}
	
	// 流1的处理逻辑
	@Override
	public void processElement1(Order value, Context ctx, Collector<Tuple2<Order, Order>> out) throws Exception {
		Order  value2 = state2.value();
		// 流2不为空表示流2先来了，直接将两个流拼接发到下游
		if (value2 != null) {
			out.collect(Tuple2.of(value, value2));
			// 清空流2对用的state信息
			state2.clear();
			// 流2来了就可以删除定时器了，并把定时器的状态清除
			ctx.timerService().deleteEventTimeTimer(timeState.value());
			timeState.clear();
		} else {
			// 流2还没来，将流1放入state1中，
			state1.update(value);
			// 并注册一个1分钟的定时器，流1中的 eventTime + 60s
			long time = value.getTime() + 60000;
			timeState.update(time);
			ctx.timerService().registerEventTimeTimer(time);
		}
	}
	
	// 流2的处理逻辑与流1的处理逻辑类似
	@Override
	public void processElement2(Order value, Context ctx, Collector<Tuple2<Order, Order>> out) throws Exception {
		Order value1 = state1.value();
		if (value1 != null) {
			out.collect(Tuple2.of(value1, value));
			state1.clear();
			ctx.timerService().deleteEventTimeTimer(timeState.value());
			timeState.clear();
		} else {
			state2.update(value);
			long time = value.getTime()+ 60000;
			timeState.update(time);
			ctx.timerService().registerEventTimeTimer(time);
		}
	}
	
	@Override
	public void onTimer(long timestamp, OnTimerContext ctx, Collector<Tuple2<Order, Order>> out) throws Exception {
		super.onTimer(timestamp, ctx, out);
		// 定时器触发了，即1分钟内没有收到两个流
		// 流1不为空，则将流1侧切输出
		if (state1.value() != null) {
		ctx.output(outputTag1, state1.value());
		}
	
		// 流2不为空，则将流2侧切输出
		if (state2.value() != null) {
		ctx.output(outputTag2, state2.value());
		}
	
		state1.clear();
		state2.clear();
	}
});

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