MapReduce实践 Uber数据分析

public static class ExtractTripMapper extends Mapper<Object, Text, Text, IntWritable>
{
    private IntWritable tripNum; // trip 值
    String specifyDate = "MM/DD/YYYY";
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("M/d/y");  // date转化格式
    LocalDate date;
    String dayOfWeek;

    public void map(Object key, Text value, Context context) throws IOException, InterruptedException
    {
        String[] splitArray = value.toString().split(","); // 对字符串进行切分
        specifyDate = splitArray[1];
        // 使用try来处理不和谐的数据
        try{
            date = LocalDate.parse(specifyDate,formatter);
            dayOfWeek = date.getDayOfWeek().toString();
            tripNum =  new IntWritable(new Integer(splitArray[3]));
        }
        catch (DateTimeParseException e){
            e.printStackTrace();
            return;
        }

        context.write(new Text(splitArray[0] + "+" + dayOfWeek), tripNum);
    }
}

public static class SumReducer extends Reducer<Text, IntWritable, Text, IntWritable>
{
    public void reduce(Text key, Iterable<IntWritable> values, Context context)
            throws IOException, InterruptedException
    {
        int sum = 0;
        for (IntWritable val : values)
        {
            sum += val.get();
        }
        context.write(key, new IntWritable(sum));
    }
}