Spring data mongoDB学习（2）

Spring链接MongoDB的两种方法
在用MongoDB和Spring时，第一件事就是用IoC容器创建一个com.mongodb.mongoDB对象。
1、利用基于bean 元数据的Java创建MongoDB的实例
2、利用基于bean 元数据的XML创建MongoDB的实例

首先，利用第一种方法：
下面利用Java创建Mongo实例。
1、利用com.mongodb.mongo创建Mongo实例 AppConfig类内容如下：

import java.net.UnknownHostException;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.mongodb.Mongo;

@Configuration
public class AppConfig {

    public @Bean Mongo mongo() throws UnknownHostException{
        return new Mongo("localhost");
    }

2、利用org.springframework.data.mongodb.core.MongoFactoryBean创建mongo   

    @Bean
    public MongoFactoryBean mongo(){
        MongoFactoryBean mongo = new MongoFactoryBean();
        mongo.setHost("localhost");
        return mongo;
        }

2、利用XML创建Mongo实例。
首先，找到app-context.xml文件，进行mongodb的一些配置

    <?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/context
          http://www.springframework.org/schema/context/spring-context-3.0.xsd
          *http://www.springframework.org/schema/data/mongo http://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsd*
          http://www.springframework.org/schema/beans
          http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
    <!-- Default bean name is 'mongo' -->
    <mongo:mongo host="localhost" port="27017"/>

</beans>

复制集的配置：

<mongo:mongo id="replicaSetMongo" replica-set="127.0.0.1:27017,localhost:27018"/>

建立新Spring项目，进行验证：
3、利用XML配置文件，如方法2.
在测试类里添加main方法如下：

public static void main(String[] args) throws Exception {
        MongoOperations mongoOps = new MongoTemplate(new SimpleMongoDbFactory(new Mongo(), "mongodb"));

        mongoOps.insert(new Company("zkwpr", 23));

        log.info(mongoOps.findOne(new Query(where("name").is("zkwpr")), Company.class));
    }

运行程序，发现插入成功！

总结：
1、Spring 和Mongo连接的方法，加上第一天学习的方法，总共有三种。
2、在不同的环境下，利用XML配置mongo的信息，需要注意xml文件的不同。
如：在Spring MVC中，就需要在root-context.xml里进行配置。配置内容为：

<?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/context
     http://www.springframework.org/schema/context/spring-context-3.0.xsd
     http://www.springframework.org/schema/data/mongo 
     http://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsd
     http://www.springframework.org/schema/beans 
     http://www.springframework.org/schema/beans/spring-beans.xsd">
   <context:annotation-config />
    <!-- Root Context: defines shared resources visible to all other web components -->
        <mongo:mongo host="localhost" port="27017"/>            
</beans>

在Spring MVC结合Maven项目中，就需要在applicationContext-data.xml中进行配置。配置内容如下：

![这里写图片描述](https://img-blog.youkuaiyun.com/20150318154802411)

<?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:jpa="http://www.springframework.org/schema/data/jpa"
    xmlns:mongo="http://www.springframework.org/schema/data/mongo"
    xsi:schemaLocation=
    "http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/context 
    http://www.springframework.org/schema/context/spring-context-4.0.xsd
    http://www.springframework.org/schema/data/jpa 
    http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
    http://www.springframework.org/schema/data/mongo 
    http://www.springframework.org/schema/data/mongo/spring-mongo-1.5.xsd">

   <context:annotation-config />

    <context:component-scan base-package="xxx.xxxxxx.xxxxxx" />

    <mongo:repositories base-package="xxx.xxxxxx.xxxxxx" />

    <!-- Default bean name is 'mongo' -->
    <mongo:mongo host="localhost" port="27017"/>

    <bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate">
        <constructor-arg ref="mongo"/>
        <constructor-arg name="databaseName" value="xxxxx"/>
    </bean>
</beans>