MongoDB Helper的简单封装

db.properties

#mongodb数据库配置文件

#数据库server所在的ip地址

ip=127.0.0.1 

#mongodb服务port号

port=27017

#要连接的库

dbName=yc

#username

uname=

#password

password=

#默认的连接集合

collectionName=voting



DBHelper

package com.yc.votingsys.dao;

import java.net.UnknownHostException;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

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;

import com.mongodb.WriteResult;

import com.yc.votingsys.utils.LogUtil;

import com.yc.votingsys.utils.StringUtil;

public class DBHelper {

private static Mongo mongo=null;

private DB db=null;

private DBCollection collection=null;

/**

 * 连接到server

 */

static{

try {

mongo= new Mongo(MyPro.getInstance().getProperty("id"),Integer.parseInt( MyPro.getInstance().getProperty("port"))
);

} catch (UnknownHostException e) {

LogUtil.log.error(e.toString());

e.printStackTrace();

} catch (MongoException e) {

LogUtil.log.error(e.toString());

e.printStackTrace();

}  

}

/**

 * 获取数据库连接

 * @param dbName：数据库名

 * @param uname：登陆数据库的username

 * @param pwd：登录password

 * @return：成功返回true

 */

public boolean getDb(String dbName,String uname,String pwd){

db=mongo.getDB(MyPro.getInstance().getProperty("dbName"));

//校验用户password是否正确 

if(!StringUtil.isNull(uname) && !StringUtil.isNull(pwd)){ //假设给定了username和password

if (!db.authenticate(uname, pwd.toCharArray())){  

LogUtil.log.error("username或password错误，连接MongoDB数据库失败....");

return false;

}else{  

LogUtil.log.error("连接MongoDB数据库成功...."); 

return true;

}

}else{ //假设没有给定，则读取配置文件里配置的username和password

String unames=MyPro.getInstance().getProperty("uname");

String pwds=MyPro.getInstance().getProperty("password");

//校验用户password是否正确 

if(!StringUtil.isNull(unames) && !StringUtil.isNull(pwds)){

if (!db.authenticate(unames, pwds.toCharArray())){  

LogUtil.log.error("username或password错误，连接MongoDB数据库失败....");

return false;

}else{  

LogUtil.log.error("连接MongoDB数据库成功...."); 

return true;

}

}else{

return true;

}

}

}

/**

 * 关闭数据库连接

 * @param mongo：server

 * @param db：数据库

 */

public void closeAll(Mongo mongo,DB db){

if(db!=null){

db.requestDone();

}

//
if(mongo!=null){

//
mongo.close();

//
}

}

/**

 * 获取指定的集合

 * @param collectionName：集合名称

 * @param dbName：数据库名

 * @param uname：登陆数据库的username

 * @param pwd：登录password

 * @return：返回获取到的集合

 */

public DBCollection getDBCollection(String collectionName,String dbName,String uname,String pwd){

if(getDb(dbName,uname,pwd)){ //连接数据库成功

db.requestStart(); //启动

if(collectionName==null){

collectionName=MyPro.getInstance().getProperty("collectionName");

}

collection=db.getCollection(collectionName); //获取指定的集合

}else{

throw new RuntimeException("数据库连接失败。请检查username和password...");

}

return collection;

}

/**

 * 加入对象

 * @param map

 * @param collection

 * @return

 */

public int addObject(Map<String,Object> map,String collectionName){

WriteResult result=null;

try {

if(collectionName==null){

collection=this.getDBCollection(null, null, null, null);

}else{

collection=this.getDBCollection(collectionName, null, null, null);

}

result=collection.save(  new BasicDBObject(map) );

} catch (Exception e) {

LogUtil.log.error(e); 

e.printStackTrace();

} finally{

this.closeAll(mongo, db);

}

return result.getN();

}

/**

 * 加入对象

 * @param map

 * @param collection

 * @return

 */

public int addObjects(Map<String,String> map,String collectionName){

WriteResult result=null;

try {

if(collectionName==null){

collection=this.getDBCollection(null, null, null, null);

}else{

collection=this.getDBCollection(collectionName, null, null, null);

}

result=collection.save(  new BasicDBObject(map) );

} catch (Exception e) {

LogUtil.log.error(e); 

e.printStackTrace();

} finally{

this.closeAll(mongo, db);

}

return result.getN();

}

/**

 * 查询单个结果

 * @param params

 * @param collectionName

 * @return

 */

public Map<String,Object> findOne(Map<String,String> params,String collectionName){

Map<String,Object> map=new HashMap<String,Object>();

try {

if(collectionName==null){

collection=this.getDBCollection(null, null, null, null);

}else{

collection=this.getDBCollection(collectionName, null, null, null);

}

DBObject object;

if(params!=null){

object=collection.findOne( new BasicDBObject(params) );

}else{

object=collection.findOne();

}

Set<String> keys=object.keySet();

for(String key:keys){

map.put(key, object.get(key));

}

}catch (MongoException e) {

LogUtil.log.error(e); 

e.printStackTrace();

}finally{

this.closeAll(mongo, db);

}

return map;

}

public Object findOneToObject(Map<String,String> params,String collectionName){

DBObject object = null;

try {

if(collectionName==null){

collection=this.getDBCollection(null, null, null, null);

}else{

collection=this.getDBCollection(collectionName, null, null, null);

}

if(params!=null){

object=collection.findOne( new BasicDBObject(params) );

}else{

object=collection.findOne();

}

}catch (MongoException e) {

LogUtil.log.error(e); 

e.printStackTrace();

}finally{

this.closeAll(mongo, db);

}

return object;

}

public List<Object> find(Map<String,Object> params,String collectionName){

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

try {

if(collectionName==null){

collection=this.getDBCollection(null, null, null, null);

}else{

collection=this.getDBCollection(collectionName, null, null, null);

}

DBCursor cursor;

if(params!=null){

cursor=collection.find(new BasicDBObject(params) );

}else{

cursor=collection.find();

}

DBObject object;

while(cursor.hasNext()){

object=cursor.next();

list.add(object);

}

}catch (MongoException e) {

LogUtil.log.error(e); 

e.printStackTrace();

}finally{

this.closeAll(mongo, db);

}

return list;

}

/**

 * 获取总记录条数

 * @param params：參数列表

 * @return：总记录数

 */

public int getTotal(Map<String,Object> params,String collectionName){

int total=0;

try {

if(collectionName==null){

collection=this.getDBCollection(null, null, null, null);

}else{

collection=this.getDBCollection(collectionName, null, null, null);

}

if(params!=null){

total=(int) collection.count( new BasicDBObject(params) );

}else{

total=(int) collection.count();

}

}catch (MongoException e) {

LogUtil.log.error(e); 

e.printStackTrace();

}finally{

this.closeAll(mongo, db);

}

return total;

}

/**

 * 更新信息

 * @param map：条件

 * @param params：改动的值

 * @param collectionName

 * @return

 */

public int update(Map<String,Object> map,Map<String,Map<String,Object>> params,String collectionName){

WriteResult result = null;

try {

if(collectionName==null){

collection=this.getDBCollection(null, null, null, null);

}else{

collection=this.getDBCollection(collectionName, null, null, null);

}

BasicDBObject object=new BasicDBObject();

if(params!=null){

Set<String> set=params.keySet();

for(String key:set){

object.append(key,params.get(key));

}

}

if(map!=null){

result=collection.update(new BasicDBObject(map),object);

}else{

result=collection.update(null,new BasicDBObject(params));

}

}catch (MongoException e) {

LogUtil.log.error(e); 

e.printStackTrace();

}finally{

this.closeAll(mongo, db);

}

return result.getN();

}

}