1、DBCollection的管理
package com.boonya.mongo;
import java.util.Set;
import com.mongodb.DBCollection;
public class CollectionManager {
public static DBCollection getDbCollection(String collectionName){
return DBConnection.getInstance().getCollection(collectionName.equals("")?"myCollection":collectionName);
}
public String getCollectionNames(){
String strNames="";
Set<String> colls =DBConnection.getInstance().getCollectionNames();
for (String cname : colls) {
strNames+=cname+",";
}
return strNames;
}
}
2、并发操作管理
package com.boonya.mongo;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import com.mongodb.WriteConcern;
public class ConcurrencyManager {
private static DBCollection coll= CollectionManager.getDbCollection("myCollection");
/**
* If you want to ensure complete consistency in a “session” (maybe an http request),* you would want the driver to use the same socket,which you can achieve by using a
* “consistent request”. Call requestStart() before your operations and requestDone()
* to release the connection back to the pool:
* DB and DBCollection are completely thread safe. In fact,they are cached so you get
* the same instance no matter what
*/
public void insertData(){
DB db=DBConnection.getInstance();
db.requestStart();
try {
db.requestEnsureConnection();
//do something
} finally {
db.requestDone();
}
}
/**
* Since by default a connection is given back to the pool after each request,you may
* wonder how calling getLastError() works after a write. You should actually use a
* write concern like WriteConcern.SAFE instead of calling getLastError() manually.
* The driver will then call getLastError() before putting the connection back in the pool.
*
* WriteConcern.NONE No exceptions thrown.
* WriteConcern.NORMAL Exceptions are only thrown when the primary node is unreachable for
* a read,or the full replica set is unreachable.
* WriteConcern.SAFE Same as the above,but exceptions thrown when there is a server error
* on writes or reads. Calls getLastError().
* WriteConcern.REPLICAS_SAFE Tries to write to two separate nodes. Same as the above,but
* will throw an exception if two writes are not possible.
* WriteConcern.FSYNC_SAFE Same as WriteConcern.SAFE,but also waits for write to be written to disk.
*
*/
public void writeConcern(){
coll.insert(new BasicDBObject("name","boonya").append("age",21),WriteConcern.SAFE);
// is equivalent to
DB db=DBConnection.getInstance();
DBCollection coll=CollectionManager.getDbCollection("myCollection");
db.requestStart();
try {
coll.insert(new BasicDBObject("name",21));
DBObject err = db.getLastError();
System.out.println(err);
} finally {
db.requestDone();
}
}
}
3、数据库管理
package com.boonya.mongo;
import java.net.UnknownHostException;
import com.mongodb.MongoClient;
public class DatabaseManager {
public String getDatabaseNames() throws UnknownHostException{
String strNames="";
MongoClient mongoClient;
mongoClient = new MongoClient();
for (String name : mongoClient.getDatabaseNames()) {
strNames+=name+",";
}
return strNames;
}
public void dropDatabase(String databaseName) throws UnknownHostException{
MongoClient mongoClient = new MongoClient();
mongoClient.dropDatabase(databaseName);
}
}
4、文档管理
package com.boonya.mongo;
import java.util.ArrayList;
import java.util.List;
import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
public class DocumentManager {
private static DBCollection coll= CollectionManager.getDbCollection("myCollection");
public void insertADocument(){
BasicDBObject doc = new BasicDBObject("name","MongoDB").append("type","database")
.append("count",1)
.append("info",new BasicDBObject("x",203).append("y",102));
coll.insert(doc);
}
/**
* PRINT BELOW:
* { "_id" : "49902cde5162504500b45c2c",* "name" : "MongoDB",* "type" : "database",* "count" : 1,* "info" : { "x" : 203,"y" : 102}}
* @return
*/
public DBObject findTheFirstDocument(){
System.out.println("collection count:"+coll.getCount());
DBObject myDoc = coll.findOne();
System.out.println(myDoc);
return myDoc;
}
public List<DBObject> getADocumentsByCursor(){
List<DBObject> docs=new ArrayList<DBObject>();
DBCursor cursor =coll.find();
try {
while(cursor.hasNext()) {
DBObject obj=cursor.next();
System.out.println(obj);
docs.add(obj);
}
return docs;
} finally {
cursor.close();
}
}
/**
* PRINT LIKE THIS:
* { "_id" : "49903677516250c1008d624e","i" : 71 }
*/
public void queryADocument(){
BasicDBObject query = new BasicDBObject("i",71);
DBCursor cursor =coll.find();
cursor = coll.find(query);
try {
while(cursor.hasNext()) {
System.out.println(cursor.next());
}
} finally {
cursor.close();
}
}
public void editQueryRegular(){
//db.things.find({j: {$ne: 3},k: {$gt: 10} });
BasicDBObject query = new BasicDBObject("j",new BasicDBObject("$ne",3)
.append("k",new BasicDBObject("$gt",10)));
DBCursor cursor = coll.find(query);
try {
while(cursor.hasNext()) {
System.out.println(cursor.next());
}
} finally {
cursor.close();
}
}
public void getAsetDocument(){
BasicDBObject query = new BasicDBObject("i",50)); // e.g. find all where i > 50
// query = new BasicDBObject("i",20).
// append("$lte",30)); // i.e. 20 < i <= 30
DBCursor cursor = coll.find(query);
try {
while(cursor.hasNext()) {
System.out.println(cursor.next());
}
} finally {
cursor.close();
}
}
}
5、索引管理
package com.boonya.mongo;
import java.util.List;
import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
public class IndexManager {
private static DBCollection coll= CollectionManager.getDbCollection("myCollection");
public void createIndex(){
// create index on "i",ascending
coll.createIndex(new BasicDBObject("i",1));
}
public List<DBObject> getIndexList(){
List<DBObject> list = coll.getIndexInfo();
for (DBObject o : list) {
System.out.println(o);
list.add(o);
}
return list;
}
}
6、预读取机制
package com.boonya.mongo;
import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.ReadPreference;
public class ReadPreferences {
private static DBCollection coll= CollectionManager.getDbCollection("myCollection");
/**
* ReadPreference.primary();
* ReadPreference.primaryPreferred();
* ReadPreference.secondary();
* ReadPreference.secondaryPreferred();
* ReadPreference.nearest();
*/
public void read(){
DBObject query = new BasicDBObject("name","simple doc");
//Read from primary if available,otherwise a secondary.
ReadPreference preference = ReadPreference.primaryPreferred();
DBCursor cur = new DBCursor(coll,query,(DBObject) preference);
//Read from any member node from the set of nodes which respond the fastest.
//The responsiveness of a node is measured with pings. Any node whose ping
//time is within 15 milliseconds of the node with the lowest ping time is considered near.
DBObject result =coll.findOne(query,(DBObject) ReadPreference.nearest());
// initialize a properly tagged read preference
ReadPreference tagged_pref =ReadPreference.secondaryPreferred(new BasicDBObject("datacenter","Los Angeles"));
// include the tagged read preference in this request}}
DBObject result1=coll.findOne(new BasicDBObject("name","simple doc"),(DBObject) tagged_pref);
// read from either LA or US_West
DBObject tagSetOne = new BasicDBObject("datacenter","Los Angeles");
DBObject tagSetTwo = new BasicDBObject("region","US_West");
ReadPreference pref =ReadPreference.primaryPreferred(tagSetOne,tagSetTwo);
}
}