mongodb java API查询例子

mongovue中查询字段PcBlackRegion，不包含'台湾'的所有数据：

{"PcBlackRegion":{'$regex' : '^((?!台湾).)*$', '$options' : 'i'}，查询结果中如果只想包含qipuId,PcBlackRegion则只需要在fields字段中包含：{"qipuId":1,"PcBlackRegion":1}

官网链接：https://www.mkyong.com/mongodb/java-mongodb-query-document/

Java MongoDB : Query document

By mkyong | May
10, 2011 | Updated : April 2, 2013 | Viewed : 144,320 times +1,021 pv/w

In this tutorial, we show you few common ways to get or query document from collection.

Test Data

Insert 5 dummy documents for testing.

{ "_id" : { "$oid" : "id"} , "number" : 1 , "name" : "mkyong-1"}
{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "mkyong-2"}
{ "_id" : { "$oid" : "id"} , "number" : 3 , "name" : "mkyong-3"}
{ "_id" : { "$oid" : "id"} , "number" : 4 , "name" : "mkyong-4"}
{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "mkyong-5"}

1. Find() examples

1.1 Get first matched document only.

DBObject doc = collection.findOne();
System.out.println(dbObject);

Output

{ "_id" : { "$oid" : "id"} , "number" : 1 , "name" : "mkyong-1"}

1.2 Get all matched documents.

DBCursor cursor = collection.find();
while(cursor.hasNext()) {
System.out.println(cursor.next());
}

Output

{ "_id" : { "$oid" : "id"} , "number" : 1 , "name" : "mkyong-1"}
{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "mkyong-2"}
{ "_id" : { "$oid" : "id"} , "number" : 3 , "name" : "mkyong-3"}
{ "_id" : { "$oid" : "id"} , "number" : 4 , "name" : "mkyong-4"}
{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "mkyong-5"}

1.3 Get single field from matched document.

BasicDBObject allQuery = new BasicDBObject();
BasicDBObject fields = new BasicDBObject();
fields.put("name", 1);

DBCursor cursor = collection.find(allQuery, fields);
while (cursor.hasNext()) {
System.out.println(cursor.next());
}

Output

{ "_id" : { "$oid" : "id"} , "name" : "mkyong-1"}
{ "_id" : { "$oid" : "id"} , "name" : "mkyong-2"}
{ "_id" : { "$oid" : "id"} , "name" : "mkyong-3"}
{ "_id" : { "$oid" : "id"} , "name" : "mkyong-4"}
{ "_id" : { "$oid" : "id"} , "name" : "mkyong-5"}

2. Find() and Comparison

2.1 Get all documents where 

number = 5

.

BasicDBObject whereQuery = new BasicDBObject();
whereQuery.put("number", 5);
DBCursor cursor = collection.find(whereQuery);
while(cursor.hasNext()) {
System.out.println(cursor.next());
}

Output

{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "mkyong-5"}

2.2 

$in

 example – Get documents where 

number
in 2, 4 and 5

.

BasicDBObject inQuery = new BasicDBObject();
List<Integer> list = new ArrayList<Integer>();
list.add(2);
list.add(4);
list.add(5);
inQuery.put("number", new BasicDBObject("$in", list));
DBCursor cursor = collection.find(inQuery);
while(cursor.hasNext()) {
System.out.println(cursor.next());
}

Output

{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "mkyong-2"}
{ "_id" : { "$oid" : "id"} , "number" : 4 , "name" : "mkyong-4"}
{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "mkyong-5"}

2.3 

$gt $lt

 example – Get documents where 

5
> number > 2 

.

BasicDBObject gtQuery = new BasicDBObject();
gtQuery.put("number", new BasicDBObject("$gt", 2).append("$lt", 5));
DBCursor cursor = collection.find(gtQuery);
while(cursor.hasNext()) {
System.out.println(cursor.next());
}

Output

{ "_id" : { "$oid" : "id"} , "number" : 3 , "name" : "mkyong-3"}
{ "_id" : { "$oid" : "id"} , "number" : 4 , "name" : "mkyong-4"}

2.4 

$ne

 example – Get documents where 

number
!= 4 

.

BasicDBObject neQuery = new BasicDBObject();
neQuery.put("number", new BasicDBObject("$ne", 4));
DBCursor cursor = collection.find(neQuery);
while(cursor.hasNext()) {
System.out.println(cursor.next());
}

Output

{ "_id" : { "$oid" : "id"} , "number" : 1 , "name" : "mkyong-1"}
{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "mkyong-2"}
{ "_id" : { "$oid" : "id"} , "number" : 3 , "name" : "mkyong-3"}
{ "_id" : { "$oid" : "id"} , "number" : 5 , "name" : "mkyong-5"}

3. find() and Logical

3.1 

$and

 example – get documents where 

number
= 2 and name = 'mkyong-2'

.

BasicDBObject andQuery = new BasicDBObject();
List<BasicDBObject> obj = new ArrayList<BasicDBObject>();
obj.add(new BasicDBObject("number", 2));
obj.add(new BasicDBObject("name", "mkyong-2"));
andQuery.put("$and", obj);

System.out.println(andQuery.toString());

DBCursor cursor = collection.find(andQuery);
while (cursor.hasNext()) {
System.out.println(cursor.next());
}

Output

{ "$and" : [ { "number" : 2} , { "name" : "mkyong-2"}]}

{ "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "mkyong-2"}

4. find() and Regex

Find document with regular expression pattern.
4.1 

$regex

 example – get documents where 

name
like pattern 'Mky.*-[1-3]', case insensitive

.

BasicDBObject regexQuery = new BasicDBObject();
regexQuery.put("name",
new BasicDBObject("$regex", "Mky.*-[1-3]")
.append("$options", "i"));

System.out.println(regexQuery.toString());

DBCursor cursor = collection.find(regexQuery);
while (cursor.hasNext()) {
System.out.println(cursor.next());
}

Output

{ "name" : { "$regex" : "Mky.*-[1-3]" , "$options" : "i"}}

{ "_id" : { "$oid" : "515ad59e3004c89329c7b259"} , "number" : 1 , "name" : "mkyong-1"}
{ "_id" : { "$oid" : "515ad59e3004c89329c7b25a"} , "number" : 2 , "name" : "mkyong-2"}
{ "_id" : { "$oid" : "515ad59e3004c89329c7b25b"} , "number" : 3 , "name" : "mkyong-3"}

There are more…

Read this MongoDB operator documentation for complete set of query operators
supported in MongoDB.

5. Full Example

package com.mkyong.core;

import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

/**
* Java MongoDB : Query document
*
* @author mkyong
*
*/
public class QueryApp {

public static void insertDummyDocuments(DBCollection collection) {

List<DBObject> list = new ArrayList<DBObject>();

Calendar cal = Calendar.getInstance();

for (int i = 1; i <= 5; i++) {

BasicDBObject data = new BasicDBObject();
data.append("number", i);
data.append("name", "mkyong-" + i);
// data.append("date", cal.getTime());

// +1 day
cal.add(Calendar.DATE, 1);

list.add(data);

}

collection.insert(list);

}

public static void main(String[] args) {

try {

Mongo mongo = new Mongo("localhost", 27017);
DB db = mongo.getDB("yourdb");

// get a single collection
DBCollection collection = db.getCollection("dummyColl");

insertDummyDocuments(collection);

System.out.println("1. Find first matched document");
DBObject dbObject = collection.findOne();
System.out.println(dbObject);

System.out.println("\n1. Find all matched documents");
DBCursor cursor = collection.find();
while (cursor.hasNext()) {
System.out.println(cursor.next());
}

System.out.println("\n1. Get 'name' field only");
BasicDBObject allQuery = new BasicDBObject();
BasicDBObject fields = new BasicDBObject();
fields.put("name", 1);

DBCursor cursor2 = collection.find(allQuery, fields);
while (cursor2.hasNext()) {
System.out.println(cursor2.next());
}

System.out.println("\n2. Find where number = 5");
BasicDBObject whereQuery = new BasicDBObject();
whereQuery.put("number", 5);
DBCursor cursor3 = collection.find(whereQuery);
while (cursor3.hasNext()) {
System.out.println(cursor3.next());
}

System.out.println("\n2. Find where number in 2,4 and 5");
BasicDBObject inQuery = new BasicDBObject();
List<Integer> list = new ArrayList<Integer>();
list.add(2);
list.add(4);
list.add(5);
inQuery.put("number", new BasicDBObject("$in", list));
DBCursor cursor4 = collection.find(inQuery);
while (cursor4.hasNext()) {
System.out.println(cursor4.next());
}

System.out.println("\n2. Find where 5 > number > 2");
BasicDBObject gtQuery = new BasicDBObject();
gtQuery.put("number", new BasicDBObject("$gt", 2).append("$lt", 5));
DBCursor cursor5 = collection.find(gtQuery);
while (cursor5.hasNext()) {
System.out.println(cursor5.next());
}

System.out.println("\n2. Find where number != 4");
BasicDBObject neQuery = new BasicDBObject();
neQuery.put("number", new BasicDBObject("$ne", 4));
DBCursor cursor6 = collection.find(neQuery);
while (cursor6.hasNext()) {
System.out.println(cursor6.next());
}

System.out.println("\n3. Find when number = 2 and name = 'mkyong-2' example");
BasicDBObject andQuery = new BasicDBObject();

List<BasicDBObject> obj = new ArrayList<BasicDBObject>();
obj.add(new BasicDBObject("number", 2));
obj.add(new BasicDBObject("name", "mkyong-2"));
andQuery.put("$and", obj);

System.out.println(andQuery.toString());

DBCursor cursor7 = collection.find(andQuery);
while (cursor7.hasNext()) {
System.out.println(cursor7.next());
}

System.out.println("\n4. Find where name = 'Mky.*-[1-3]', case sensitive example");
BasicDBObject regexQuery = new BasicDBObject();
regexQuery.put("name",
new BasicDBObject("$regex", "Mky.*-[1-3]")
.append("$options", "i"));

System.out.println(regexQuery.toString());

DBCursor cursor8 = collection.find(regexQuery);
while (cursor8.hasNext()) {
System.out.println(cursor8.next());
}

collection.drop();

System.out.println("Done");

} catch (UnknownHostException e) {
e.printStackTrace();
} catch (MongoException e) {
e.printStackTrace();
}

}
}