Hadoop 自定义序列化MapReduce实战

旧城等待， 2022-09-05 00:14 211阅读 0赞

#### 前言 ####

我笑了，跑个mapReduce，执行了三十秒

#### 自定义序列化 ####

这次实现手机号上行下行流量的求和，模拟使用MapReduce实现

#### Bean ####

import org.apache.hadoop.io.Writable;
    
    import java.io.DataInput;
    import java.io.DataOutput;
    import java.io.IOException;
    
    //1 继承 Writable 接口
    public class FlowBean implements Writable {
        
        private long upFlow; //上行流量
        private long downFlow; //下行流量
        private long sumFlow; //总流量
    
        //2 提供无参构造
        public FlowBean() {
        
        }
    
        //3 提供三个参数的 getter 和 setter 方法
        public long getUpFlow() {
        
            return upFlow;
        }
    
        public void setUpFlow(long upFlow) {
        
            this.upFlow = upFlow;
        }
    
        public long getDownFlow() {
        
            return downFlow;
        }
    
        public void setDownFlow(long downFlow) {
        
            this.downFlow = downFlow;
        }
    
        public long getSumFlow() {
        
            return sumFlow;
        }
    
        public void setSumFlow(long sumFlow) {
        
            this.sumFlow = sumFlow;
        }
    
        public void setSumFlow() {
        
            this.sumFlow = this.upFlow + this.downFlow;
        }
    
        //4 实现序列化和反序列化方法,注意顺序一定要保持一致
        @Override
        public void write(DataOutput dataOutput) throws IOException {
        
            dataOutput.writeLong(upFlow);
            dataOutput.writeLong(downFlow);
            dataOutput.writeLong(sumFlow);
        }
    
        @Override
        public void readFields(DataInput dataInput) throws IOException {
        
            this.upFlow = dataInput.readLong();
            this.downFlow = dataInput.readLong();
            this.sumFlow = dataInput.readLong();
        }
    
        //5 重写 ToString
        @Override
        public String toString() {
        
            return upFlow + "\t" + downFlow + "\t" + sumFlow;
        }
    }

#### Mapper——处理的是每行数据 ####

import org.apache.hadoop.io.LongWritable;
    import org.apache.hadoop.io.Text;
    import org.apache.hadoop.mapreduce.Mapper;
    
    import java.io.IOException;
    
    public class FlowMapper extends Mapper<LongWritable, Text, Text, FlowBean> {
        
        // 输入的value
        private Text outK = new Text();
        // 输出的value
        private FlowBean outV = new FlowBean();
    
        @Override
        protected void map(LongWritable key, Text value, Mapper.Context context)
                throws IOException, InterruptedException {
        
            //1 获取一行数据,转成字符串
            // 18833025128 100 200
            String line = value.toString();
            //2 切割数据
            String[] split = line.split(" ");
            //3 抓取我们需要的数据:手机号,上行流量,下行流量
            String phone = split[0];
            String up = split[1];
            String down = split[2];
            //4 封装 outK outV
            outK.set(phone);
            outV.setUpFlow(Long.parseLong(up));
            outV.setDownFlow(Long.parseLong(down));
            outV.setSumFlow(Long.parseLong(up)+Long.parseLong(down));
            System.out.println("mapper.................结束");
            System.out.println(outV);
            //5 写出 outK outV
            context.write(outK, outV);
        }
    }

#### Reducer——对Mapper的将结果进行整合 ####

import org.apache.hadoop.io.Text;
    import org.apache.hadoop.mapreduce.Reducer;
    import java.io.IOException;
    
    
    public class FlowReducer extends Reducer<Text,FlowBean, Text,FlowBean> {
        
        @Override
        protected void reduce(Text key, Iterable<FlowBean> values, Context context) throws IOException, InterruptedException {
        
           // 给定的是key以及集合的累加
            FlowBean flowBean = new FlowBean();
            long upFlow = 0;
            long downFlow = 0;
            long sumFlow = 0;
            for (FlowBean f:values){
        
                upFlow +=f.getUpFlow();
                downFlow +=f.getDownFlow();
                sumFlow +=f.getSumFlow();
            }
            flowBean.setUpFlow(upFlow);
            flowBean.setDownFlow(downFlow);
            flowBean.setSumFlow(sumFlow);
    
            System.out.println("reducer................结束");
            System.out.println(flowBean);
            context.write(key,flowBean);
        }
    }

#### Driver——任务驱动类，用于执行任务 ####

import org.apache.hadoop.conf.Configuration;
    import org.apache.hadoop.fs.Path;
    import org.apache.hadoop.io.Text;
    
    import org.apache.hadoop.mapreduce.Job;
    import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
    import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
    
    import java.io.FileOutputStream;
    import java.io.IOException;
    
    
    public class FlowDriver {
        
        // 这里为了直观显示参数 使用了硬编码的形式，实际开发中可以通过外部传参
        private static final String HDFS_URL = "hdfs://192.168.56.80:9000";
        private static final String HADOOP_USER_NAME = "root";
    
        // 需要打包并在服务器上执行  hadoop jar hadoop-word-count-1.0.jar  com.heibaiying.flow.FlowDriver
        public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
        
            // 获取job
            Configuration configuration = new Configuration();
            System.setProperty("HADOOP_USER_NAME", HADOOP_USER_NAME);
            // 指明HDFS的地址
            configuration.set("fs.defaultFS", HDFS_URL);
            Job job = Job.getInstance(configuration);
            // 设置jar
            job.setJarByClass(FlowDriver.class);
            // 关键mapper、reducer
            job.setMapperClass(FlowMapper.class);
            job.setReducerClass(FlowReducer.class);
            // 设置mapper输出的key和value
            job.setMapOutputKeyClass(Text.class);
    
            job.setOutputValueClass(FlowBean.class);
            // 设置最终输出的key、value类型
            job.setOutputKeyClass(Text.class);
            job.setOutputValueClass(FlowBean.class);
            FileInputFormat.setInputPaths(job,new Path("/test/text.txt"));
            FileOutputFormat.setOutputPath(job,new Path("/test/text1.txt"));
            boolean b = job.waitForCompletion(true);
            System.out.println(b);
        }
    }

#### 测试 ####

准备文件text.txt，内容为18888888 100 200  
需要打包到hadoop集群上，执行

hadoop jar hadoop-word-count-1.0.jar  com.heibaiying.flow.FlowDriver

输出为自定义bean  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzg4OTg0MQ_size_16_color_FFFFFF_t_70]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzg4OTg0MQ_size_16_color_FFFFFF_t_70]: /images/20220829/f5eea1702a334e4fa502d2277b84c3b2.png