import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
@Override
public LineChartStatisticsResult sumCommentsGroupByCreatedDate(TimeRangedStatisticsRequest request) {
    // Emit UTC millis (only year, month, week and day are taken into account) of createdDate as key
    // Value is set to 1 to sum up later (reduce)
    String map = "function () {  " +
            "   var day = Date.UTC(this.createdDate.getFullYear(), this.createdDate.getMonth(), this.createdDate.getDate()); " +
            "   emit(day.toString(), 1); " +
            "}";
    // Reduce all the values for one "key" (for details about key, see above) by summing up each value.
    final String reduce = "function(key,values){ return values.length;}";

    Query filter = Query.query(Criteria.where("createdDate").gte(request.getStartDate()).lte(request.getEndDate()));

    MapReduceResults<KeyValuePair> sumResults = mongoTemplate.mapReduce(
            filter,
            COLLECTION_NAME,
            map,
            reduce,
            KeyValuePair.class
    );

    return toLineChartStatisticsResult(sumResults, request);
}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
private LineChartStatisticsResult toLineChartStatisticsResult(MapReduceResults<KeyValuePair> sumResults, TimeRangedStatisticsRequest request) {
    Map<String, Long> results = new LinkedHashMap<>();

    for (KeyValuePair vo : sumResults) {
        DateTime dateFromDbId;
        try {
            dateFromDbId = new DateTime(Long.parseLong(vo.getId()), DateTimeZone.UTC);
        } catch (NumberFormatException nfe) {
            throw new IllegalStateException("MapReduce emitted wrong format for id / key field. Expected UTC millis.", nfe);
        }

        results.put(StatisticsActionUtil.formatDate(dateFromDbId), vo.getValue());
    }

    return new LineChartStatisticsResult(
            CHART_NAME_SUM_COMMENTS,
            StatisticsActionUtil.fillMap(StatisticsActionUtil.getDefaultMap(request), results)
    );
}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
@Override
public Map<String, Integer> analyseIngredientsByPopularity()
{
    /*
     * This class references two JavaScript functions, the mapper and the
     * reducer, respectively.
     */
    MapReduceResults<IngredientAnalysis> results = mongoTemplate.mapReduce("menu",
            "classpath:ingredientsmap.js",
            "classpath:ingredientsreduce.js",
            IngredientAnalysis.class);

    Map<String, Integer> analysis = new HashMap<String, Integer>();

    for (IngredientAnalysis ingredientAnalysis : results)
    {
        analysis.put(ingredientAnalysis.getId(), ingredientAnalysis.getValue());
    }

    return analysis;
}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
@Override
public DailyStatistic aggregateDailyStatistics(String day) {
   
   // Build a query to pre-select the statistics that will be aggregated.
   Query query = new Query(Criteria.where("day").is(day));
   
   // Execute a MapReduce command.
   MapReduceResults<WrappedDailyStatistic> results = template.mapReduce(query, "dailyStatistic", 
         "classpath:mapDailyStatisticForADay.js", 
         "classpath:reduceDailyStatisticForADay.js", 
         WrappedDailyStatistic.class);
   
   // Output some debug messages.
   if (log.isDebugEnabled()){
      log.debug("aggregateDailyStatistics mapReduce for day " + day);
      log.debug("aggregateDailyStatistics mapReduce result counts: " + results.getCounts());
      for (WrappedDailyStatistic wdt : results){
         log.debug("aggregateDailyStatistics mapReduce result value: " + wdt.getValue());
      }
   }
   
   // We've got a result if we've got an output.
   if (results.getCounts().getOutputCount() > 0){
      return results.iterator().next().getValue();
   }
   
   // Build and return an empty object otherwise?
   DailyStatistic statistic = new DailyStatistic();
   statistic.setDay(day);
   statistic.setDailyCount(0);
   return statistic;
}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
@Override
public List<BarChartStatisticsResult> countCommentsGroupByProject(int projectCount) {

    final String map = "function(){ emit(this.project.$id , 1 ); } ";
    final String reduce = "function(key,values){ return values.length;}";

    MapReduceResults<KeyValuePair> results = mongoTemplate.mapReduce(COLLECTION_NAME, map, reduce, KeyValuePair.class);

    final List<KeyValuePair> sortedList = new ArrayList<>();
    for (KeyValuePair result : results) {
        sortedList.add(result);
    }

    Collections.sort(sortedList);

    List<BarChartStatisticsResult> res = new ArrayList<>(projectCount);
    for (KeyValuePair kv : sortedList) {
        ProjectEntity project = mongoTemplate.findOne(new Query(Criteria.where("id").is(kv.getId())), ProjectEntity.class);

        if (project != null) {
            res.add(new BarChartStatisticsResult(kv.getId(), project.getTitle(), kv.getValue()));
        }
        if (res.size() >= projectCount) {
            break;
        }
    }

    return res;
}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
@Override
public <E> MapReduceResults<E> mapReduce(String mapFunction, String reduceFunction, Class<E> entityClass) {
    return mongoTemplate.mapReduce(collection, mapFunction, reduceFunction, entityClass);
}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
public static void main(String[] args) {
	
	ApplicationContext ctx = new AnnotationConfigApplicationContext(
			AppConfig.class);	
	
	MongoOperations mongoOperation = (MongoOperations) ctx
			.getBean("mongoTemplate");
	
	MapReduceResults<CameraCount> mrResults = mongoOperation.mapReduce("photographers", "classpath:mapByCameraMakeModel.js", "classpath:reduce.js", CameraCount.class);
	
	for (CameraCount cameraCount : mrResults) {
	  System.out.println("make is " + cameraCount.getId().getMake());
	  System.out.println("model is " + cameraCount.getId().getModel());
	  System.out.println("count is " + cameraCount.getValue().getCount());
	}
	
	((ConfigurableApplicationContext)ctx).close();

}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
public static void main(String[] args) {

		ApplicationContext ctx = new AnnotationConfigApplicationContext(
				AppConfig.class);	
		
		MongoOperations mongoOperation = (MongoOperations) ctx
				.getBean("mongoTemplate");
	
		MapReduceResults<ValueObject> mrResults = mongoOperation.mapReduce("metadata", "classpath:mapByCameraModelFStop.js", "classpath:reduce.js", ValueObject.class);
		for (ValueObject valueObject : mrResults) {
		System.out.println(valueObject);
		}

		((ConfigurableApplicationContext)ctx).close();
	
	}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
private MapReduceResults<WidgetUsersMapReduceResult> executeUsersMapReduce() {
    return mongoOperations.mapReduce(PAGE_COLLECTION, USERS_MAP, USERS_REDUCE, getOptions(WIDGET_USERS), WidgetUsersMapReduceResult.class);
}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
private MapReduceResults<WidgetRatingsMapReduceResult> executeRatingsMapReduce() {
    return mongoOperations.mapReduce(WIDGET_COLLECTION, RATINGS_MAP, RATINGS_REDUCE, getOptions(WIDGET_RATINGS), WidgetRatingsMapReduceResult.class);
}
 

import org.springframework.data.mongodb.core.mapreduce.MapReduceResults; //导入依赖的package包/类
<E> MapReduceResults<E> mapReduce(String mapFunction, String reduceFunction, Class<E> entityClass);