Javascript 如何将mongo查询转换为java代码

我有一些复杂的javascript代码来查询MongoShell中的数据。我怎么能不费吹灰之力就得到这个java等价物呢？我已经阅读了很多教程，但似乎都需要付出巨大的努力才能获得与查询相同的结果

var trendForDate = new Date('2016-01-08T18:30:00.000Z');
 var oneMonthBack = new Date(trendForDate.getTime() - 1000 * 60 * 60 * 24 * 31);
 var trendToDate = new Date(trendForDate.getTime() + 1000 * 60 * 60 * 24);
 var loyal = "loyal";
 var newCustomer = "newCustomer";
 var loyalLost = "loyalLost";
 var dormant = "dormant";
 var lost = "lost";
 var usersForOrderDate = db.order.find({
     "status": "DELIVERED",
     "orderDate.interval_start": {
         $gte: trendForDate,
         $lt: trendToDate
     }
 }).map(function(o) {
     return o.customer
 });
 db.order.mapReduce(function() {
     emit(this.customer, {
         count: 1,
         orderDate: this.orderDate.interval_start
     })
 }, function(key, values) {
     var sum = 0;
     var lastOrderDate;
     var category;
     values.forEach(function(value) {
         if (value['orderDate']) {
             lastOrderDate = value['orderDate'];
         } else {
             lastOrderDate = value['lastOrderDate'];
         }
         sum += value['count'];
     });
     if (sum >= 5 & lastOrderDate > oneMonthBack) {
         category = loyal;
     }
     if (sum <= 4 & sum >= 1 & lastOrderDate > oneMonthBack) {
         category = newCustomer;
     }
     if (sum >= 5 & lastOrderDate < oneMonthBack) {
         category = loyalLost;
     }
     if (sum <= 4 & sum > 1 & lastOrderDate < oneMonthBack) {
         category = dormant;
     }
     if (sum == 1 & lastOrderDate < oneMonthBack) {
         category = lost;
     }
     return {
         count: sum,
         lastOrderDate: lastOrderDate,
         category: category
     };
 }, {
     query: {
         status: "DELIVERED",
         "orderDate.interval_start": {
             $lt: trendForDate
         }
     },
     out: {
         merge: "customerTrend"
     },
     finalize: function(key, value) {
         if (value.count == 1) {
             value.category = lost;
         }
         return value;
     },
     scope: {
         oneMonthBack: oneMonthBack,
         trendDate: trendForDate,
         loyal: loyal,
         newCustomer: newCustomer,
         loyalLost: loyalLost,
         dormant: dormant,
         lost: lost
     }
 });
 print(trendForDate);
 print(trendToDate);
 db.customerTrend.aggregate([{
     $match: {
         _id: {
             $in: usersForOrderDate
         }
     }
 }, {
     $group: {
         "_id": "$value.category",
         "users": {
             $sum: 1
         }
     }
 }]);

要运行以进行查询的示例文档

{ "_id" : ObjectId("546b1018e4b0ce7d5ee021ce"), "customer" : ObjectId("546b0fdde4b0ce7d5ee021cc"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2014-11-17T18:30:00Z"), "interval_end" : ISODate("2014-11-17T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1416249000000"), "jodaField_dayOfMonth" : 17, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 11, "jodaField_year" : 2014 }, "status" : "DELIVERED" }
{ "_id" : ObjectId("546b6d87e4b0ce7d5ee021e0"), "customer" : ObjectId("545f64e7e4b07a0a501276db"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2014-11-17T18:30:00Z"), "interval_end" : ISODate("2014-11-17T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1416249000000"), "jodaField_dayOfMonth" : 17, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 11, "jodaField_year" : 2014 }, "status" : "DELIVERED" }
{ "_id" : ObjectId("546c13e3e4b0ce7d5ee021f0"), "customer" : ObjectId("54696c64e4b07f3c07010b4a"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2014-11-18T18:30:00Z"), "interval_end" : ISODate("2014-11-18T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1416335400000"), "jodaField_dayOfMonth" : 18, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 11, "jodaField_year" : 2014 }, "status" : "DELIVERED" }
{ "_id" : ObjectId("546c2357e4b0ce7d5ee021fb"), "customer" : ObjectId("546c2208e4b0ce7d5ee021f9"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2014-11-18T18:30:00Z"), "interval_end" : ISODate("2014-11-18T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1416335400000"), "jodaField_dayOfMonth" : 18, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 11, "jodaField_year" : 2014 }, "status" : "DELIVERED" }
{ "_id" : ObjectId("54b0db4ee4b08e29cd9309e0"), "customer" : ObjectId("549e790fe4b09508addfcc34"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2015-01-09T18:30:00Z"), "interval_end" : ISODate("2015-01-09T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1420828200000"), "jodaField_dayOfMonth" : 9, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 1, "jodaField_year" : 2015 }, "status" : "DELIVERED" }
.....

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您是否可以编辑您的问题以显示一些示例文档以及这些示例文档的预期聚合输出是什么？不考虑最终语言实现，如果您打算通过该函数调用在MongoDB服务器上运行

mapReduce

作业，则“mapper”和“reducer”实现仍将处于运行状态“JavaScript”。因此，如果我编写Perl/Python/C++甚至Java，那么函数仍然是用JavaScript编写的（通常作为“字符串”）并发送到服务器执行。因此没有任何变化。除了上面的代码显然已被破坏之外（您无法从“reducer”输出与“mapper”不同的结构），但这实际上是一个不同的问题。@chridam，编辑了这个问题以显示输出，即您想要的预期输出还是实际输出？一些要测试的示例文档如何？这是我得到的实际输出，我想要完全相同的输出

{ "_id" : ObjectId("546b1018e4b0ce7d5ee021ce"), "customer" : ObjectId("546b0fdde4b0ce7d5ee021cc"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2014-11-17T18:30:00Z"), "interval_end" : ISODate("2014-11-17T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1416249000000"), "jodaField_dayOfMonth" : 17, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 11, "jodaField_year" : 2014 }, "status" : "DELIVERED" }
{ "_id" : ObjectId("546b6d87e4b0ce7d5ee021e0"), "customer" : ObjectId("545f64e7e4b07a0a501276db"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2014-11-17T18:30:00Z"), "interval_end" : ISODate("2014-11-17T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1416249000000"), "jodaField_dayOfMonth" : 17, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 11, "jodaField_year" : 2014 }, "status" : "DELIVERED" }
{ "_id" : ObjectId("546c13e3e4b0ce7d5ee021f0"), "customer" : ObjectId("54696c64e4b07f3c07010b4a"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2014-11-18T18:30:00Z"), "interval_end" : ISODate("2014-11-18T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1416335400000"), "jodaField_dayOfMonth" : 18, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 11, "jodaField_year" : 2014 }, "status" : "DELIVERED" }
{ "_id" : ObjectId("546c2357e4b0ce7d5ee021fb"), "customer" : ObjectId("546c2208e4b0ce7d5ee021f9"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2014-11-18T18:30:00Z"), "interval_end" : ISODate("2014-11-18T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1416335400000"), "jodaField_dayOfMonth" : 18, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 11, "jodaField_year" : 2014 }, "status" : "DELIVERED" }
{ "_id" : ObjectId("54b0db4ee4b08e29cd9309e0"), "customer" : ObjectId("549e790fe4b09508addfcc34"), "orderDate" : { "jodaType" : "org.joda.time.DateTime", "interval_start" : ISODate("2015-01-09T18:30:00Z"), "interval_end" : ISODate("2015-01-09T18:30:00Z"), "jodaField_zone" : "UTC", "time" : NumberLong("1420828200000"), "jodaField_dayOfMonth" : 9, "jodaField_hourOfDay" : 18, "jodaField_minuteOfHour" : 30, "jodaField_millisOfSecond" : 0, "jodaField_monthOfYear" : 1, "jodaField_year" : 2015 }, "status" : "DELIVERED" }
.....