Mongodb driver for java 使用样例，mongodb样例,MongoDB的数据==

Mongodb driver for java 使用样例，mongodb样例,MongoDB的数据==

MongoDB的数据

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{ "_id" : ObjectId("54d3509f30c0ed0f308ed1ef"), "cust_id" : "A123", "amount" : 500.0, "status" : "A"}{ "_id" : ObjectId("54d350a830c0ed0f308ed1f0"), "cust_id" : "A123", "amount" : 250.0, "status" : "A"}{ "_id" : ObjectId("54d350b430c0ed0f308ed1f1"), "cust_id" : "A123", "amount" : 250.0, "status" : "A"}{ "_id" : ObjectId("54d350be30c0ed0f308ed1f2"), "cust_id" : "B212", "amount" : 200.0, "status" : "A"}{ "_id" : ObjectId("54d350c030c0ed0f308ed1f3"), "cust_id" : "B212", "amount" : 200.0, "status" : "A"}{ "_id" : ObjectId("54d350d030c0ed0f308ed1f4"), "cust_id" : "A123", "amount" : 300.0, "status" : "D"}

import org.bson.Document;import com.mongodb.BasicDBObject;import com.mongodb.DBCollection;import com.mongodb.DBObject;import com.mongodb.MapReduceCommand;import com.mongodb.MapReduceOutput;import com.mongodb.MongoClient;import com.mongodb.client.FindIterable;import com.mongodb.client.MapReduceIterable;import com.mongodb.client.MongoCollection;import com.mongodb.client.MongoCursor;import com.mongodb.client.MongoDatabase;import com.mongodb.util.JSON;public class MongoDBClientTest { private static MongoClient mongoClient; private static MongoDatabase db; static {  mongoClient = new MongoClient("localhost", 27017);  db = mongoClient.getDatabase("local"); } public MongoDBClientTest() {  super(); } public static void main(String[] args) {  MongoDBClientTest clientTest = new MongoDBClientTest();  clientTest.testQuery();  clientTest.testInsert();  clientTest.testDelete();  clientTest.testToJsonObject();  clientTest.testMapReduce(); }//test search private void testQuery() {  System.err.println("===========going to select==========");  MongoCollection collection = db.getCollection("posts");  BasicDBObject query = new BasicDBObject("cust_id", "B212");  BasicDBObject returnField1 = new BasicDBObject("cust_id", 1);  BasicDBObject returnField2 = new BasicDBObject("status", 1);  FindIterable iterable = collection.find(query);  MongoCursor cursor = iterable.iterator();  while (cursor.hasNext()) {   org.bson.Document user = cursor.next();   System.out.println(user.get("cust_id"));   System.out.println(user.toString());  }  cursor.close(); }//test insert private void testInsert() {  System.err.println("===========going to insert==========");  MongoCollection collection = db.getCollection("posts");  Document doc = new Document();  doc.put("cust_id", "A111");  doc.put("amount", 210);  doc.put("status", "C");  collection.insertOne(doc);  FindIterable iterable = collection.find();  MongoCursor cursor = iterable.iterator();  while (cursor.hasNext()) {   org.bson.Document user = cursor.next();   // System.out.println(user.get("cust_id"));   System.out.println(user.toString());  } }//test delete private void testDelete() {  System.err.println("===========going to delete==========");  MongoCollection collection = db.getCollection("posts");  BasicDBObject query = new BasicDBObject("status", "C");  collection.deleteMany(query);  FindIterable iterable = collection.find();  MongoCursor cursor = iterable.iterator();  while (cursor.hasNext()) {   org.bson.Document user = cursor.next();   System.out.println(user.toString());  } }//test string to json object private void testToJsonObject() {  System.err.println("===========to json object==========");  String jsonString = "{  'title' : 'NoSQL Overview', 'description' : 'No sql database is very fast', 'by_user' : 'tutorials point', 'url' : 'http://www.tutorialspoint.com', 'tags' : [ 'mongodb', 'database', 'NoSQL' ], 'likes' : 10 }";  BasicDBObject doc = (BasicDBObject) JSON.parse(jsonString);  System.out.println(doc);  System.out.println(doc.get("tags").getClass().getCanonicalName()); }//test the map reduce private void testMapReduce() {  System.err.println("===========test map reduce==========");  MongoCollection collection = db.getCollection("posts");  String map = "function(){emit(this.cust_id,this.amount);}";  String reduce = "function(key, values){return Array.sum(values)}";  // MapReduceCommand cmd = new MapReduceCommand(collection, map, reduce,  // null, MapReduceCommand.OutputType.INLINE, null);  MapReduceIterable out = collection.mapReduce(map, reduce);  MongoCursor cursor = out.iterator();  while (cursor.hasNext()) {   System.out.println(cursor.next());  }  BasicDBObject query=new BasicDBObject("status","C");  DBCollection dbcol = mongoClient.getDB("local").getCollection("posts");  MapReduceCommand cmd = new MapReduceCommand(dbcol, map, reduce,    "outputCollection", MapReduceCommand.OutputType.INLINE, query);  MapReduceOutput out2 = dbcol.mapReduce(cmd);  for (DBObject o : out2.results()) {   System.out.println(o.toString());  }  System.out.println("Done"); }}