MongoDB Java 通用方法

最近寫了一個針對MongoDB的一些常用操作的公共類，希望對初學者有幫助。

package model.dao;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.log4j.Logger;
import org.bson.types.ObjectId;
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;
/**

MongoDB Manager
@author Ken Chau
/
public class MongoDBManager {
   private static Logger log = Logger.getLogger(MongoDBManager.class);
private static Mongo mg = null;
   private static DB db = null;
private final static MongoDBManager instance = new MongoDBManager();
/**

實例化
@return
@throws Exception
*/
public static MongoDBManager getInstance() throws Exception {

 return instance;

}
static {
   try {

    mg = new Mongo(HOST, PORT);
   db=mg.getDB(DB);

} catch (Exception e) {

    log.error("Can't connect MongoDB!");
   e.printStackTrace();

}
}
/**

獲取集合（表）
@param collection
*/
public static DBCollection getCollection(String collection) {
   return db.getCollection(collection);
}
/**

----------------------------------分割線--------------------------------------
*/
/**

插入
@param collection
@param map
*/
public void insert(String collection , Map<String, Object> map) {
   try {

    DBObject dbObject = map2Obj(map);
    getCollection(collection).insert(dbObject);

} catch (MongoException e) {

    log.error("MongoException:" + e.getMessage());

}
}
/**

批量插入
@param collection
@param list
*/
public void insertBatch(String collection ,List<Map<String, Object>> list) {
   if (list == null || list.isEmpty()) {

    return;

}
   try {

    List<DBObject> listDB = new ArrayList<DBObject>();
    for (int i = 0; i < list.size(); i++) {
         DBObject dbObject = map2Obj(list.get(i));
         listDB.add(dbObject);
    }
    getCollection(collection).insert(listDB);

} catch (MongoException e) {

    log.error("MongoException:" + e.getMessage());

}
}
/**

刪除
@param collection
@param map
*/
public void delete(String collection ,Map<String, Object> map) {
   DBObject obj = map2Obj(map);
   getCollection(collection).remove(obj);
}
/**

刪除全部
@param collection
@param map
*/
public void deleteAll(String collection) {
 List<DBObject> rs = findAll(collection);
 if (rs != null && !rs.isEmpty()) {
  for (int i = 0; i < rs.size(); i++) {
       getCollection(collection).remove(rs.get(i));
  }

 }
}

/**

批量刪除
@param collection
@param list
*/
public void deleteBatch(String collection,List<Map<String, Object>> list) {
   if (list == null || list.isEmpty()) {

    return;

}
   for (int i = 0; i < list.size(); i++) {

    getCollection(collection).remove(map2Obj(list.get(i)));

}
}
/**

計算滿足條件條數
@param collection
@param map
*/
public long getCount(String collection,Map<String, Object> map) {
   return getCollection(collection).getCount(map2Obj(map));
}
/**

計算集合總條數
@param collection
@param map
*/
public long getCount(String collection) {
   return getCollection(collection).find().count();
}
/**

更新
@param collection
@param setFields
@param whereFields
*/
public void update(String collection,Map<String, Object> setFields,

    Map<String, Object> whereFields) {

DBObject obj1 = map2Obj(setFields);
   DBObject obj2 = map2Obj(whereFields);
   getCollection(collection).updateMulti(obj1, obj2);
}
/**

查找對象（根據主鍵_id）
@param collection
@param _id
*/
public DBObject findById(String collection,String _id) {
   DBObject obj = new BasicDBObject();
   obj.put("_id", ObjectId.massageToObjectId(_id));
   return getCollection(collection).findOne(obj);
}
/**

查找集合所有對象
@param collection
*/
public List<DBObject> findAll(String collection) {
   return getCollection(collection).find().toArray();
}
/**

查找（返回一個對象）
@param map
@param collection
*/
public DBObject findOne(String collection,Map<String, Object> map) {
   DBCollection coll = getCollection(collection);
   return coll.findOne(map2Obj(map));
}
/**

查找（返回一個List<DBObject>）
@param <DBObject>
@param map
@param collection
@throws Exception
*/
public List<DBObject> find(String collection,Map<String, Object> map) throws Exception {
   DBCollection coll = getCollection(collection);
   DBCursor c = coll.find(map2Obj(map));
   if (c != null)
    return c.toArray();

   else
    return null;

}</pre>