先看一下Spring对MongoDB的配置文件mongo.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"xmlns:mongo="http://www.springframework.org/schema/data/mongo"xsi:schemaLocation="http://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-3.0.xsdhttp://www.springframework.org/schema/data/mongohttp://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsdhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd"><context:component-scan base-package="com.cher7.mongo" />
<!--replicaSetMongo 为配置多个mongos或配置多个relicasetmongo,但是所配置的必须为同一类型--><mongo:mongo id="replicaSetMongo" replica-set="${mongodb.host}"> <!-- 每个IP的连接数--><mongo:options connections-per-host="100"threads-allowed-to-block-for-connection-multiplier="50"auto-connect-retry="true"/></mongo:mongo><bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate"><constructor-arg name="mongo" ref="replicaSetMongo" /><!--mongo的数据库名称--><constructor-arg name="databaseName" value="${mongodb.dataname}" /></bean><beans profile="test"><context:property-placeholder location="classpath:config/mongodb.properties"/></beans>
</beans>

mongodb.properties代码为：

#mongodb.host=192.168.65.4:10000,192.168.65.5:10000 #此处均为mongos
mongodb.dataname=cher7

很多同学用Spring封装的MongoDB包时都会对多个MongoDB的负载均衡疑惑，Spring到底是如何做负载均衡呢？由于本文中心不是解析此问题，只做稍微解释：Spring启动了多个线程，每个线程的工作为ping一下要连接的Mongo库，取连接时间最短的Mongo为客户端提供服务。有兴趣的同学可以自己查看一下源码，此处不再详述。

继续上述。mongo.xml文件中对外提供了mongoTemplate对象，该对象即可对Mongo库进行增删改查各项操作。

本人对此作了小小封装：

package com.cher7.mongo;import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Sort;
import org.springframework.data.domain.Sort.Order;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.data.mongodb.core.query.Query;import com.cher7.util.Reflections;/*** @ClassName: BaseMongoManager* @Description:* @author zc* @date 2014-5-8 下午3:50:22* */
public class BaseMongoManager<E> {/** 日志对象 */protected static final Logger logger = Logger.getLogger(BaseMongoManager.class);@Autowiredprivate MongoTemplate mongoTemplate;public void setMongoTemplate(MongoTemplate mongoTemplate) {this.mongoTemplate = mongoTemplate;}/*** Entity的类型*/protected Class<E> entityClass;public BaseMongoManager() {this.entityClass = Reflections.getSuperClassGenricType(getClass());}/*** * @Title: findAll* @Description: 查询表格所有的数据* @return List<E> 当前实体对应的表格的所有数据。*/public List<E> findAll() {return this.findAll(null);}/*** @Title: findAll* @Description: 查询表格所有的数据* @param clazz*            该表所对应的实体* @param collcetionName*            表格名称* @return List<E>*/public List<E> findAll(String collcetionName) {if (StringUtils.isBlank(collcetionName)) {collcetionName = mongoTemplate.getCollectionName(Reflections.getSuperClassGenricType(getClass()));if (StringUtils.isBlank(collcetionName)) {collcetionName = this.entityClass.getSimpleName().toLowerCase();}logger.info("findAll's param collcetionName is null,so it default is "+ collcetionName);}return mongoTemplate.findAll(entityClass, collcetionName);}/*** * @Title: findCount* @Description:查询当前实体对应表格的所有数据的条数* @return long 总条数* @throws*/public long findCount() {long count = 0;count = mongoTemplate.count(new Query(), entityClass);return count;}/**** * @Title: insert* @Description: 入库* @param e*            实体数据* @param collectionName*            表名*/public void insert(E e, String collectionName) {mongoTemplate.insert(e, collectionName);}/*** * @Title: insert* @Description: 入库* @param e*            实体数据*/public void insert(E e) {mongoTemplate.insert(e);}/*** 生产查询语句* * @Title: createCriteria* @Description: 根据不同条件生产SQL* @param gtMap* @param ltMap* @param eqMap* @param gteMap* @param lteMap* @param regexMap* @param inMap* @param neMap* @return Criteria 查询的语句* @throws*/@SuppressWarnings("rawtypes")public Criteria createCriteria(Map<String, Object> gtMap,Map<String, Object> ltMap, Map<String, Object> eqMap,Map<String, Object> gteMap, Map<String, Object> lteMap,Map<String, String> regexMap, Map<String, Collection> inMap,Map<String, Object> neMap) {Criteria c = new Criteria();List<Criteria> listC= new ArrayList<Criteria>();Set<String> _set = null;if (gtMap != null && gtMap.size() > 0) {_set = gtMap.keySet();for (String _s : _set) {listC.add( Criteria.where(_s).gt(gtMap.get(_s)));}}if (ltMap != null && ltMap.size() > 0) {_set = ltMap.keySet();for (String _s : _set) {listC.add(  Criteria.where(_s).lt(ltMap.get(_s)));}}if (eqMap != null && eqMap.size() > 0) {_set = eqMap.keySet();for (String _s : _set) {listC.add(  Criteria.where(_s).is(eqMap.get(_s)));}}if (gteMap != null && gteMap.size() > 0) {_set = gteMap.keySet();for (String _s : _set) {listC.add( Criteria.where(_s).gte(gteMap.get(_s)));}}if (lteMap != null && lteMap.size() > 0) {_set = lteMap.keySet();for (String _s : _set) {listC.add(  Criteria.where(_s).lte(lteMap.get(_s)));}}if (regexMap != null && regexMap.size() > 0) {_set = regexMap.keySet();for (String _s : _set) {listC.add(  Criteria.where(_s).regex(regexMap.get(_s)));}}if (inMap != null && inMap.size() > 0) {_set = inMap.keySet();for (String _s : _set) {listC.add(  Criteria.where(_s).in(inMap.get(_s)));}}if (neMap != null && neMap.size() > 0) {_set = neMap.keySet();for (String _s : _set) {listC.add( Criteria.where(_s).ne(neMap.get(_s)));}}if(listC.size() > 0){Criteria [] cs = new Criteria[listC.size()];c.andOperator(listC.toArray(cs));}return c;}public Criteria createCriteria(Map<String, Object> eqMap) {return this.createCriteria(null, null, eqMap, null, null, null, null,null);}public Criteria createCriteria(Map<String, Object> eqMap,Map<String, Object> neMap) {return this.createCriteria(null, null, eqMap, null, null, null, null,neMap);}/*** * @Title: findCount* @Description: 根据各种条件查询总数* @param gtMap* @param ltMap* @param eqMap* @param gteMap* @param lteMap* @param regexMap* @param inMap* @param neMap* @return long 总数* @throws*/@SuppressWarnings("rawtypes")public long findCount(Map<String, Object> gtMap, Map<String, Object> ltMap,Map<String, Object> eqMap, Map<String, Object> gteMap,Map<String, Object> lteMap, Map<String, String> regexMap,Map<String, Collection> inMap, Map<String, Object> neMap) {long count = 0;Criteria c = this.createCriteria(gtMap, ltMap, eqMap, gteMap, lteMap,regexMap, inMap, neMap);Query query = null;if (c == null) {query = new Query();} else {query = new Query(c);}count = mongoTemplate.count(query, entityClass);return count;}/**** * @Title: findCount* @Description: 根据创建的条件查询总数* @param  queryC* @return long    返回类型* @throws*/public long findCount(Criteria queryC){Query query = new Query(queryC);return mongoTemplate.count(query, entityClass);}/*** * @Title: findCount* @Description: 根据多个种条件 or 的方式查询* @param orList*            or的查询条件的集合* @return long* @throws*/public long findCount(Criteria... orList) {long count = 0;Criteria c = new Criteria();Query query = null;if (orList != null && orList.length > 0) {c.orOperator(orList);}query = new Query(c);count = mongoTemplate.count(query, entityClass);return count;}@SuppressWarnings("rawtypes")public long findCount(Map<String, Object> gtMap, Map<String, Object> ltMap,Map<String, Object> eqMap, Map<String, String> regexMap,Map<String, Collection> inMap) {return this.findCount(gtMap, ltMap, eqMap, null, null, regexMap, inMap,null);}public long findCountByContainRegex(Map<String, Object> gtMap,Map<String, Object> ltMap, Map<String, Object> eqMap,Map<String, String> regexMap) {return this.findCount(gtMap, ltMap, eqMap, regexMap, null);}/*** * @Title: findListByPage* @Description: 根据分页+条件获取对应的实体集合* @param eqMap* @param gtMap* @param ltMap* @param gteMap* @param lteMap* @param regexMap* @param inMap* @param orders*            排序集合* @param pageIndex*            页码* @param pageSize*            每页条数* @return List<E> 实体集合* @throws*/@SuppressWarnings("rawtypes")public List<E> findListByPage(Map<String, Object> eqMap,Map<String, Object> gtMap, Map<String, Object> ltMap,Map<String, Object> gteMap, Map<String, Object> lteMap,Map<String, String> regexMap, Map<String, Collection> inMap,Map<String, Object> neMap, List<Order> orders, int pageIndex,int pageSize) {List<E> list = null;Criteria c = this.createCriteria(gtMap, ltMap, eqMap, gteMap, lteMap,regexMap, inMap, neMap);Sort sort = null;if (orders != null && orders.size() > 0) {sort = new Sort(orders);}Query query = null;if (c == null) {query = new Query();} else {query = new Query(c);}if (sort != null) {query = query.with(sort);}if (pageSize > 0) {query.skip((pageIndex - 1) * pageSize);query.limit(pageSize);}list = mongoTemplate.find(query, entityClass);return list;}/*** @Title: findOneObject* @Description: 符合条件的某一条数据* @param eqMap* @param gtMap* @param ltMap* @param gteMap* @param lteMap* @param regexMap* @param inMap* @return E 返回该数据对应的实体*/@SuppressWarnings("rawtypes")public E findObject(Map<String, Object> eqMap, Map<String, Object> gtMap,Map<String, Object> ltMap, Map<String, Object> gteMap,Map<String, Object> lteMap, Map<String, String> regexMap,Map<String, Collection> inMap) {E e = null;List<E> list = this.findList(eqMap, gtMap, ltMap, gteMap, lteMap,regexMap, inMap, null, null);if (list != null && list.size() > 0) {e = list.get(0);}return e;}/*** * @Title: findList* @Description: 多个查询条件or方式组合查询* @param orList* @return List<E>* @throws*/public List<E> findList(Criteria... orList) {return this.findListByPage(null, 0, 0, orList);}/*** * @Title: findListByOrder* @Description: 多个查询条件or方式组合查询* @param orList* @param orders* @return List<E>* @throws*/public List<E> findListByOrder(List<Order> orders, Criteria... orList) {return this.findListByPage(orders, 0, 0, orList);}/*** * @Title: findListByPage* @Description: 根据查询条件直接查询* @param  c* @param  orders* @param  pageIndex* @param  pageSize* @return List<E>    * @throws*/public List<E> findListByPage(Criteria c, List<Order> orders, int pageIndex,int pageSize){Query query = new Query(c);Sort sort = null;if (orders != null && orders.size() > 0) {sort = new Sort(orders);}if (sort != null) {query = query.with(sort);}if (pageSize > 0) {query.skip((pageIndex - 1) * pageSize);query.limit(pageSize);}return mongoTemplate.find(query, entityClass);}public List<E> findListByOrder(Criteria c, List<Order> orders){return this.findListByPage(c, orders, 0, 0);}public List<E> findList(Criteria c){return this.findListByPage(c, null, 0, 0);}/*** * @Title: findObject* @Description: 根据查询条件查询某一个object* @param  c* @return E    * @throws*/public E findObject(Criteria c){List<E> list = this.findList(c);if(list!=null && list.size()>0){return list.get(0);}return null;}/*** * @Title: findListByPage* @Description: 多个查询条件or方式组合查询* @param orList*            or的查询条件的集合* @param orders排序规则* @param pageIndex*            第几页* @param pageSize每页多少条* @return List<E> 符合条件的集合* @throws*/public List<E> findListByPage(List<Order> orders, int pageIndex,int pageSize, Criteria... orList) {List<E> list = null;Criteria c = new Criteria();Query query = null;if (orList != null && orList.length > 0) {c.orOperator(orList);}query = new Query(c);Sort sort = null;if (orders != null && orders.size() > 0) {sort = new Sort(orders);query = query.with(sort);}if (pageSize > 0) {query.skip((pageIndex - 1) * pageSize);query.limit(pageSize);}list = mongoTemplate.find(query, entityClass);return list;}@SuppressWarnings("rawtypes")public List<E> findListNotContainOrder(Map<String, Object> eqMap,Map<String, Object> gtMap, Map<String, Object> ltMap,Map<String, Object> gteMap, Map<String, Object> lteMap,Map<String, String> regexMap, Map<String, Collection> inMap,Map<String, Object> neMap) {return this.findList(eqMap, gtMap, ltMap, gteMap, lteMap, regexMap,inMap, neMap, null);}}