flink 计算热门商品

た入场券 2023-01-04 13:11 235阅读 0赞

# flink计算热门商品 #

在实验一的基础上，继续进行这个实验

首先下载这个数据集

访问https://tianchi.aliyun.com/dataset/dataDetail?dataId=649

点击下载zip文件

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzMDM0NTA1_size_16_color_FFFFFF_t_70_pic_center]

下载完毕后解压，移动到resources目录下

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzMDM0NTA1_size_16_color_FFFFFF_t_70_pic_center 1]

在myflink包内新建一个HotItems类，代码如下

/*
     * Licensed to the Apache Software Foundation (ASF) under one
     * or more contributor license agreements.  See the NOTICE file
     * distributed with this work for additional information
     * regarding copyright ownership.  The ASF licenses this file
     * to you under the Apache License, Version 2.0 (the
     * "License"); you may not use this file except in compliance
     * with the License.  You may obtain a copy of the License at
     *
     *     http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    package myflink;
    
    import org.apache.flink.api.common.functions.AggregateFunction;
    import org.apache.flink.api.common.functions.FilterFunction;
    import org.apache.flink.api.common.state.ListState;
    import org.apache.flink.api.common.state.ListStateDescriptor;
    import org.apache.flink.api.java.io.PojoCsvInputFormat;
    import org.apache.flink.api.java.tuple.Tuple;
    import org.apache.flink.api.java.tuple.Tuple1;
    import org.apache.flink.api.java.typeutils.PojoTypeInfo;
    import org.apache.flink.api.java.typeutils.TypeExtractor;
    import org.apache.flink.configuration.Configuration;
    import org.apache.flink.core.fs.Path;
    import org.apache.flink.streaming.api.TimeCharacteristic;
    import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
    import org.apache.flink.streaming.api.functions.KeyedProcessFunction;
    import org.apache.flink.streaming.api.functions.timestamps.AscendingTimestampExtractor;
    import org.apache.flink.streaming.api.functions.windowing.WindowFunction;
    import org.apache.flink.streaming.api.windowing.time.Time;
    import org.apache.flink.streaming.api.windowing.windows.TimeWindow;
    import org.apache.flink.util.Collector;
    
    import java.io.File;
    import java.net.URI;
    import java.net.URL;
    import java.sql.Timestamp;
    import java.util.ArrayList;
    import java.util.Comparator;
    import java.util.List;
    
    public class HotItems {
        
    
        public static void main(String[] args) throws Exception {
        
    
            // 创建 execution environment
            StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
            // 告诉系统按照 EventTime 处理
            env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
            // 为了打印到控制台的结果不乱序，我们配置全局的并发为1，改变并发对结果正确性没有影响
            env.setParallelism(1);
    
            // UserBehavior.csv 的本地文件路径, 在 resources 目录下
    
            URL fileUrl = HotItems.class.getClassLoader().getResource("UserBehavior.csv");
            Path filePath = Path.fromLocalFile(new File(fileUrl.toURI()));
    
    
            // 抽取 UserBehavior 的 TypeInformation，是一个 PojoTypeInfo
            PojoTypeInfo<UserBehavior> pojoType = (PojoTypeInfo<UserBehavior>) TypeExtractor.createTypeInfo(UserBehavior.class);
            // 由于 Java 反射抽取出的字段顺序是不确定的，需要显式指定下文件中字段的顺序
            String[] fieldOrder = new String[]{
        "userId", "itemId", "categoryId", "behavior", "timestamp"};
            // 创建 PojoCsvInputFormat
            PojoCsvInputFormat<UserBehavior> csvInput = new PojoCsvInputFormat<>(filePath, pojoType, fieldOrder);
    
    
            env
                    // 创建数据源，得到 UserBehavior 类型的 DataStream
                    .createInput(csvInput, pojoType)
                    // 抽取出时间和生成 watermark
                    .assignTimestampsAndWatermarks(new AscendingTimestampExtractor<UserBehavior>() {
        
                        @Override
                        public long extractAscendingTimestamp(UserBehavior userBehavior) {
        
                            // 原始数据单位秒，将其转成毫秒
                            return userBehavior.timestamp * 1000;
                        }
                    })
                    // 过滤出只有点击的数据
                    .filter(new FilterFunction<UserBehavior>() {
        
                        @Override
                        public boolean filter(UserBehavior userBehavior) throws Exception {
        
                            // 过滤出只有点击的数据
                            return userBehavior.behavior.equals("pv");
                        }
                    })
                    .keyBy("itemId")
                    .timeWindow(Time.minutes(60), Time.minutes(5))
                    .aggregate(new CountAgg(), new WindowResultFunction())
                    .keyBy("windowEnd")
                    .process(new TopNHotItems(3))
                    .print();
    
            env.execute("Hot Items Job");
        }
    
        /** 求某个窗口中前 N 名的热门点击商品，key 为窗口时间戳，输出为 TopN 的结果字符串 */
        public static class TopNHotItems extends KeyedProcessFunction<Tuple, ItemViewCount, String> {
        
    
            private final int topSize;
    
            public TopNHotItems(int topSize) {
        
                this.topSize = topSize;
            }
    
            // 用于存储商品与点击数的状态，待收齐同一个窗口的数据后，再触发 TopN 计算
            private ListState<ItemViewCount> itemState;
    
            @Override
            public void open(Configuration parameters) throws Exception {
        
                super.open(parameters);
                ListStateDescriptor<ItemViewCount> itemsStateDesc = new ListStateDescriptor<>(
                        "itemState-state",
                        ItemViewCount.class);
                itemState = getRuntimeContext().getListState(itemsStateDesc);
            }
    
            @Override
            public void processElement(
                    ItemViewCount input,
                    Context context,
                    Collector<String> collector) throws Exception {
        
    
                // 每条数据都保存到状态中
                itemState.add(input);
                // 注册 windowEnd+1 的 EventTime Timer, 当触发时，说明收齐了属于windowEnd窗口的所有商品数据
                context.timerService().registerEventTimeTimer(input.windowEnd + 1);
            }
    
            @Override
            public void onTimer(
                    long timestamp, OnTimerContext ctx, Collector<String> out) throws Exception {
        
                // 获取收到的所有商品点击量
                List<ItemViewCount> allItems = new ArrayList<>();
                for (ItemViewCount item : itemState.get()) {
        
                    allItems.add(item);
                }
                // 提前清除状态中的数据，释放空间
                itemState.clear();
                // 按照点击量从大到小排序
                allItems.sort(new Comparator<ItemViewCount>() {
        
                    @Override
                    public int compare(ItemViewCount o1, ItemViewCount o2) {
        
                        return (int) (o2.viewCount - o1.viewCount);
                    }
                });
                // 将排名信息格式化成 String, 便于打印
                StringBuilder result = new StringBuilder();
                result.append("====================================\n");
                result.append("时间: ").append(new Timestamp(timestamp-1)).append("\n");
                for (int i=0; i<allItems.size() && i < topSize; i++) {
        
                    ItemViewCount currentItem = allItems.get(i);
                    // No1:  商品ID=12224  浏览量=2413
                    result.append("No").append(i).append(":")
                            .append("  商品ID=").append(currentItem.itemId)
                            .append("  浏览量=").append(currentItem.viewCount)
                            .append("\n");
                }
                result.append("====================================\n\n");
    
                // 控制输出频率，模拟实时滚动结果
                Thread.sleep(1000);
    
                out.collect(result.toString());
            }
        }
    
        /** 用于输出窗口的结果 */
        public static class WindowResultFunction implements WindowFunction<Long, ItemViewCount, Tuple, TimeWindow> {
        
    
            @Override
            public void apply(
                    Tuple key,  // 窗口的主键，即 itemId
                    TimeWindow window,  // 窗口
                    Iterable<Long> aggregateResult, // 聚合函数的结果，即 count 值
                    Collector<ItemViewCount> collector  // 输出类型为 ItemViewCount
            ) throws Exception {
        
                Long itemId = ((Tuple1<Long>) key).f0;
                Long count = aggregateResult.iterator().next();
                collector.collect(ItemViewCount.of(itemId, window.getEnd(), count));
            }
        }
    
        /** COUNT 统计的聚合函数实现，每出现一条记录加一 */
        public static class CountAgg implements AggregateFunction<UserBehavior, Long, Long> {
        
    
            @Override
            public Long createAccumulator() {
        
                return 0L;
            }
    
            @Override
            public Long add(UserBehavior userBehavior, Long acc) {
        
                return acc + 1;
            }
    
            @Override
            public Long getResult(Long acc) {
        
                return acc;
            }
    
            @Override
            public Long merge(Long acc1, Long acc2) {
        
                return acc1 + acc2;
            }
        }
    
        /** 商品点击量(窗口操作的输出类型) */
        public static class ItemViewCount {
        
            public long itemId;     // 商品ID
            public long windowEnd;  // 窗口结束时间戳
            public long viewCount;  // 商品的点击量
    
            public static ItemViewCount of(long itemId, long windowEnd, long viewCount) {
        
                ItemViewCount result = new ItemViewCount();
                result.itemId = itemId;
                result.windowEnd = windowEnd;
                result.viewCount = viewCount;
                return result;
            }
        }
    
        /** 用户行为数据结构 **/
        public static class UserBehavior {
        
            public long userId;         // 用户ID
            public long itemId;         // 商品ID
            public int categoryId;      // 商品类目ID
            public String behavior;     // 用户行为, 包括("pv", "buy", "cart", "fav")
            public long timestamp;      // 行为发生的时间戳，单位秒
        }
    }

pom文件与实验一相同

然后点击运行，如果如下图

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzMDM0NTA1_size_16_color_FFFFFF_t_70_pic_center 2]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzMDM0NTA1_size_16_color_FFFFFF_t_70_pic_center]: /images/20221119/af6599ceb07f4fed87a0a83d80acfbf3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzMDM0NTA1_size_16_color_FFFFFF_t_70_pic_center 1]: /images/20221119/dd39ae4fde7b40dcadb32a2f7a859d85.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzMDM0NTA1_size_16_color_FFFFFF_t_70_pic_center 2]: /images/20221119/46a823547f834c8a8374841f8d57241d.png