The code copy is as follows:
package mymaven;
import java.net.UnknownHostException;
import java.util.Set;
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;
public class Test {
public static void main(String[] args) throws UnknownHostException, MongoException {
Mongo mongo = new Mongo("172.27.9.104", 27017); // Connect to the database
DB db = mongo.getDB("mytestdb"); // Database
Set<String> cols = db.getCollectionNames(); // Get all collections in the database (similar to getting tables in relational databases)
// Print out the collection in the database, here it should be null
for (String s: cols) {
System.out.println(s);
}
DBCollection collection = db.getCollection("mytestcoll"); // Create a collection
collection.drop(); // Delete the collection and automatically rebuild when inserting data
BasicDBObject obj = new BasicDBObject(); // Initialize a basic DB object, the DB object inserted into the database is
obj.put("from", "blog.ihomer.net"); // Put in several key-value pairs
obj.put("to", "forum.ithomer.net");
obj.put("subject", "ithomer.net");
collection.insert(obj); // Insert object
DBObject dbobj = collection.findOne(); // View a record, findOne()=find().limit(1);
System.out.println(dbobj); // Print out the data you just inserted
// Insert 10 {ranking:i} data
for (int i = 0; i < 10; i++) {
collection.insert(new BasicDBObject().append("ranking", i));
}
System.out.println("count: " + collection.getCount()); // Print the total number of data in the collection
DBCursor cursor = collection.find(); // Then we use this cursor to iterate over the collection
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
// Simple conditional query, query records with ranking of 1
BasicDBObject query = new BasicDBObject();
query.put("ranking", 1);
cursor = collection.find(query);
System.out.println("collection find({/"ranking/":1}):");
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
// Complex conditional query, query records with ranking greater than or equal to 5 and less than 9
query = new BasicDBObject();
query.put("ranking", new BasicDBObject("$gte", 5).append("$lt", 9));
cursor = collection.find(query);
System.out.println("collection find({/"ranking/":[5-9)}):");
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
// mongo.dropDatabase("mytestdb"); // Finally delete our test database
}
}
Running results:
The code copy is as follows:
mytestcoll
system.indexes
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10107"} , "from" : "blog.ihomer.net" , "to" : "forum.ihomer.net" , "subject" : "ihomer.net"}
count: 11
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10107"} , "from" : "blog.ihomer.net" , "to" : "forum.ihomer.net" , "subject" : "ihomer.net"}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10108"} , "ranking" : 0}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10109"} , "ranking" : 1}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010a"} , "ranking" : 2}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010b"} , "ranking" : 3}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010c"} , "ranking" : 4}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010d"} , "ranking" : 5}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010e"} , "ranking" : 6}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010f"} , "ranking" : 7}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10110"} , "ranking" : 8}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10111"} , "ranking" : 9}
collection find({"ranking":1}):
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10109"} , "ranking" : 1}
collection find({"ranking":[5-9)}):
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010d"} , "ranking" : 5}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010e"} , "ranking" : 6}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010f"} , "ranking" : 7}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10110"} , "ranking" : 8}
Example of mongodb array:
The code copy is as follows:
@SuppressWarnings("unchecked")
public static void loadMediaTags(List<MediaEntity> mediaEntityList) {
mediaEntityList.clear();
try {
Mongo mongo = new Mongo(CosineCluster.gMongo_HOST, CosineCluster.gMongo_PORT);
DB db = mongo.getDB(CosineCluster.gMongo_DB);
DBCollection collection = db.getCollection(CosineCluster.gMongo_Coll_Media);
DBCursor cursor = collection.find();
int index = 0;
long startTime = System.currentTimeMillis();
while(cursor.hasNext()){
BasicDBObject obj = (BasicDBObject) cursor.next();
long id = obj.getLong("_id");
ArrayList<String> tagList = (ArrayList<String>) obj.get("tag");// tag
ArrayList<String> keywordList = (ArrayList<String>)obj.get("keyword");// keyword
ArrayList<Integer> copyrightList = (ArrayList<Integer>)obj.get("copyright");// copyright
MediaEntity mediaEntity = new MediaEntity();
mediaEntity.setId(id);
// tag
for(int j=0; j<tagList.size(); j++) {
mediaEntity.addTag(tagList.get(j));
int tagId = getTagInt(tagList.get(j));
mediaEntity.addTag(tagId);
}
// actors
ArrayList<DBObject> actorsObjList = (ArrayList<DBObject>)obj.get("actors");// actors
for(int j=0; j<actorsObjList.size(); j++) {
mediaEntity.addActor((String) actorsObjList.get(j).get("name"));
int actorId = getActorInt((String)actorsObjList.get(j).get("name"));
mediaEntity.addActor(actorId);
}
// director
ArrayList<DBObject> directorObjList = (ArrayList<DBObject>)obj.get("director");// director
for(int j=0; j<directorObjList.size(); j++) {
mediaEntity.addDirector((String) directorObjList.get(j).get("name"));
int directorId = getDirectorInt((String) directorObjList.get(j).get("name"));
mediaEntity.addDirector(directorId);
}
// keyword
for(int j=0; j<keywordList.size(); j++) {
mediaEntity.addKeyword(keywordList.get(j));
int keywordId = getKeywordInt(keywordList.get(j));
mediaEntity.addKeyword(keywordId);
}
// copyright
for(int j=0; j<copyrightList.size(); j++) {
mediaEntity.addCopyright(copyrightList.get(j));
}
mediaEntityList.add(mediaEntity);
index++;
if(index > 100) {
break;
}
System.out.println(index + " --- mediaEntity : " + mediaEntity.toString());
}
long costTime = System.currentTimeMillis() - startTime;
System.out.println("load data costTime = " + index + "; costTime = " + costTime/1000f);
} catch (Exception e) {
e.printStackTrace();
}
}
public static int getTagInt(String tag) {
int tagIntId = -1;
try {
MongoClient mongo = new MongoClient(CosineCluster.gMongo_HOST, CosineCluster.gMongo_PORT);
DB db = mongo.getDB(CosineCluster.gMongo_DB);
DBCollection tagmapCollection = db.getCollection("recommend_tag_map");
DBCursor cursor = tagmapCollection.find(new BasicDBObject("name", tag));
if(cursor == null || cursor.toArray().size() <= 0) {// Process mapping keywords less than 2 or n, the same below
return tagIntId;
}
DBObject obj = cursor.toArray().get(0);
String name = tag;
tagIntId = (Integer) obj.get("id");
int num = (Integer) obj.get("num");
mongo.close();
} catch (UnknownHostException e) {
e.printStackTrace();
}
return tagIntId;
}
public static int getActorInt(String actor) {
int actorIntId = -1;
try {
MongoClient mongo = new MongoClient(CosineCluster.gMongo_HOST, CosineCluster.gMongo_PORT);
DB db = mongo.getDB(CosineCluster.gMongo_DB);
DBCollection tagmapCollection = db.getCollection("recommend_actor_map");
DBCursor cursor = tagmapCollection.find(new BasicDBObject("name", actor));
if(cursor == null || cursor.toArray().size() <= 0) {
return actorIntId;
}
DBObject obj = cursor.toArray().get(0);
String name = actor;
actorIntId = (Integer) obj.get("id");
int num = (Integer) obj.get("num");
mongo.close();
} catch (UnknownHostException e) {
e.printStackTrace();
}
return actorIntId;
}