導(dǎo)入依賴

在pom文件中添加以下依賴织盼，其中mongo-java-driver提供了java操作mongoDB的基本API吆豹，而morphia則是在其之上封裝了Java對(duì)象和BSON對(duì)象的映射關(guān)系惋增。

<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongo-java-driver</artifactId>
    <version>3.2.1</version>
</dependency>

<dependency>
    <groupId>org.mongodb.morphia</groupId>
    <artifactId>morphia</artifactId>
    <version>1.0.1</version>
</dependency>

構(gòu)建Datastore對(duì)象

// mongo客戶端用于連接服務(wù)端的地址串
String mongoClientURIString = 
    "mongodb://192.168.0.100,192.168.14.101/?replicaSet=test&readPreference=nearest";
MongoClientURI mongoClientURI = new MongoClientURI(mongoClientURIString);
// 構(gòu)建出mongo客戶端對(duì)象
MongoClient mongoClient = new MongoClient(mongoClientURI);
Morphia morphia = new Morphia();
// 告訴morphia到哪個(gè)包下面去找實(shí)體類
morphia.mapPackage("com.elong.web.gcCollection.model");
// 構(gòu)建Datastore對(duì)象古胆，其中`gcLog`是數(shù)據(jù)庫(kù)名稱
Datastore datastore = morphia.createDatastore(mongoClient, "gcLog");
// 確保索引生效
datastore.ensureIndexes();

為實(shí)體加上注解

通常一個(gè)實(shí)體映射為mongo中的一個(gè)collection雹洗，我們通過(guò)注解的方式告訴morphia這個(gè)映射關(guān)系渐北。@Entity("gcLogItem")表示這個(gè)類對(duì)應(yīng)mongo中的名為gcLogItem的collection阿逃；@Id表示這個(gè)屬性對(duì)應(yīng)主鍵字段。

注解的其它用法參見這里。

@Entity("gcLogItem")
public class BaseGcItem {
    @Id
    private String id;

    private String host;

    /**
     * other fields go here ...
     */

    /**
     * getters and setters methods go here ...
     */
}

通過(guò)Datastore對(duì)象操作mongoDB

構(gòu)建完Datastore對(duì)象以后就可以利用這個(gè)對(duì)象提供的API來(lái)操作mongoDB了恃锉。詳細(xì)用法搀菩，請(qǐng)看這里。

下面這些例子展示了一些用法：

@Repository
public class GcLogItemDaoImpl implements GcLogItemDao {

    @Autowired
    private DbClient dbClient;

    @Override
    public String insert(BaseGcItem gcItem) {
        Datastore datastore = dbClient.getDatastore();
        return (String)datastore.save(gcItem).getId();
    }

    @Override
    public Iterator<Key<BaseGcItem>> insert(List<BaseGcItem> gcItemList) {
        Datastore datastore = dbClient.getDatastore();
        return datastore.save(gcItemList).iterator();
    }

    @Override
    public List<BaseGcItem> getAll() {
        Query<BaseGcItem> query = dbClient.getDatastore()
            .createQuery(BaseGcItem.class);
        return query.asList();
    }

    @Override
    @SuppressWarnings("unchecked")
    public List<String> getDistinctHost() {
        DBCollection dbCollection = dbClient.getDatastore()
            .getCollection(BaseGcItem.class);
        return (List<String>)dbCollection.distinct("host");
    }

    @Override
    public List<BaseGcItem> getByHost(String host) {
        Query<BaseGcItem> query = dbClient.getDatastore()
            .createQuery(BaseGcItem.class)
            .field("host").equal(host)
            .order("-timestampOfGc");
        return query.asList();
    }


    @Override
    public List<BaseGcItem> getByGcItemType(GcItemType gcItemType) {
        Query<BaseGcItem> query = dbClient.getDatastore()
            .createQuery(BaseGcItem.class)
            .field("gcItemType").equal(gcItemType)
            .order("-timestampOfGc");
        return query.asList();
    }

    @Override
    public int removeByDateRange(Date startDate, Date endDate) {
        Datastore datastore = dbClient.getDatastore();
        Query<BaseGcItem> query = datastore
            .createQuery(BaseGcItem.class)
            .field("timestampOfGc").greaterThanOrEq(startDate)
            .field("timestampOfGc").lessThan(endDate);
        return datastore.delete(query).getN();
    }

}