我在MongoDB中使用MapReduce時遇到了錯誤

首先我使用Windows XP 32位操作系統，MongoDB作爲NoSQL DB和Eclipse作爲編輯器程序。我從我的學校得到了關於MapReduce的任務，因此我決定使用mapreduce查找多少工作年齡和非工作人口。我用這個代碼來輸入數據，並保存爲Insert.java：我在MongoDB中使用MapReduce時遇到了錯誤

package mongox; 

import com.mongodb.BasicDBObject; 
import com.mongodb.Mongo; 
import com.mongodb.DB; 
import com.mongodb.DBCollection; 

public class Insert { 
    public static void main(String[] args) { 
    try{ 
     Mongo mongox = new Mongo(); 
     DB db = mongox.getDB("DBPublic"); 
     DBCollection koleksi = db.getCollection("lancestorvalley"); 
     BasicDBObject object = new BasicDBObject(); 

     object = new BasicDBObject(); 
     object.put("NIK", "7586930211"); 
     object.put("Name", "Richard Bou"); 
     object.put("Sex", "M"); 
     object.put("Age", "31"); 
     object.put("Blood", "A"); 
     object.put("Status", "Married"); 
     object.put("Education", "Bachelor degree"); 
     object.put("Employment", "Labor"); 
     koleksi.insert(object); 
    } 
    catch(Exception e){ 
     System.out.println(e.toString()); 
    } 
} 
}

我使用此代碼爲MapReduce和保存爲Mapreduce.java：

package mongox; 

    import com.mongodb.DB; 
    import com.mongodb.DBCollection; 
    import com.mongodb.DBObject; 
    import com.mongodb.MapReduceCommand; 
    import com.mongodb.MapReduceOutput; 
    import com.mongodb.Mongo; 

    public class Mapreduce { 
    public static void main(String[] args) { 
    try{ 
     Mongo mongox = new Mongo("localhost", 27017); 
     DB db = mongox.getDB("DBPublic"); 
     DBCollection koleksi = db.getCollection("lancestorvalley"); 

     String map = "function() { "+ 
     "var category; " + 
     "if (this.Age >= 15 && this.Age <=59) "+ 
     "category = 'Working-Age Population'; " + 
     "else " + 
     "category = 'Non-Working-Age Population'; "+ 
     "emit(category, {Nama: this.Nama});}"; 

     String reduce = "function(key, values) { " + 
     "var sum = 0; " + 
     "values.forEach(function(doc) { " + 
     "sum += 1; "+ 
     "}); " + 
     "return {data: sum};} "; 

     MapReduceCommand cmd = new MapReduceCommand(koleksi, map, reduce, 
       null, MapReduceCommand.OutputType.INLINE, null); 
     MapReduceOutput out = koleksi.mapReduce(cmd); 

     for (DBObject o : out.results()) { 
      System.out.println(o.toString()); 
      } 
    } 
    catch(Exception e){ 
     e.printStackTrace();; 
    } 
    } 
    }

我已經輸入5000個數據，當我運行Mapreduce.java的輸出是：

{ "_id" : "Non-Working-age population" , "value" : { "data" : 41.0}} 
    { "_id" : "Working-age Population" , "value" : { "data" : 60.0}}

我的代碼在Mapreduce.java中有什麼問題嗎？爲什麼輸出結果只有數據大約是5000？希望有人能幫助我，謝謝面前的傢伙

來源

2014-09-11 Kelvin Rosv

這會更好用聚合完成。查看[reduce function requirements]（http://docs.mongodb.org/manual/reference/command/mapReduce/#mapreduce-reduce-cmd）。 Map/reduce可以在同一個鍵上多次運行reduce函數，並且需要一個數組作爲值。 – wdberkeley 2014-09-15 15:49:00

MongoDB的文檔明確地規定以下，這可能是未預期的行爲的原因：

Platform Support 

Starting in version 2.2, MongoDB does not support Windows XP. Please use a more recent version of Windows to use more recent releases of MongoDB.

此外：

MongoDB for Windows 32-bit runs on any 32-bit version of Windows newer than Windows XP. 32-bit versions of MongoDB are only intended for older systems and for use in testing and development systems. 32-bit versions of MongoDB only support databases smaller than 2GB.

來源

2014-09-11 13:16:55 vmr

我試過在Windows 7（相同的代碼和5000數據），並且輸出也出錯（與Windows XP相同）:( – 2014-09-12 12:15:36

我在MongoDB中使用MapReduce時遇到了錯誤

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