使用morphia对基于mongodb应用开发

@Entity(value="stores",noClassnameStored=true)public class Store {@Idprivate ObjectId id;private String name;private String desc;@Embeddedpublic Place place;@Overridepublic String toString() { return "Store [desc=" + desc + ", id=" + id + ", name=" + name + ", place=" + place + "]";}public Store(){}public Store(String name, String desc, Place place) {this.name = name;this.desc = desc;this.place = place;}//省略getter,setters}

@Embeddedpublic class Place {private String name = "";@Indexed(IndexDirection.GEO2D)private double[] loc = null;public Place(String name, double[] loc) {this.name = name;this.loc = loc;}public Place() {}@Overridepublic String toString() {return "Place [loc=" + Arrays.toString(loc) + ", name=" + name + "]";}//省略getter,setters}

package morphia.dao;import java.util.List;import morphia.model.Place;import morphia.model.Store;import com.google.code.morphia.Datastore;import com.google.code.morphia.dao.BasicDAO;import com.google.code.morphia.query.Query;public class StoreDao extends BasicDAO<Store, String> {public StoreDao(Datastore ds) {super(ds);ds.ensureIndexes();ds.ensureCaps();}/** * 查找离 p 最近的5个店铺 * @param p * @return */public List<Store> findNearPlace(Place p) {return ds.createQuery(Store.class).field("place.loc").near(p.getLoc()[0], p.getLoc()[1]).limit(5).asList();}/** * 查找离 p 最近的5个肯德基店 * @param p * @return */public List<Store> findKFCNearPlace(Place p) {return ds.createQuery(Store.class).filter("name", "肯德基").field("place.loc").near(p.getLoc()[0], p.getLoc()[1]).limit(5).asList();}/** * 删除所有店铺 */public void deleteAllStore(){Query<Store> q = ds.createQuery(Store.class);ds.delete(q);}}

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??? 接下来就可以写测试类了：

package mongo.morphia.test;import java.util.List;import morphia.dao.PlaceDao;import morphia.dao.StoreDao;import morphia.model.Place;import morphia.model.Store;import com.google.code.morphia.Datastore;import com.google.code.morphia.Morphia;import com.mongodb.Mongo;public class StoreDaoTest {public static String[] STORE_TYPE = {"肯德基","麦当劳","必胜客","吉野家","蒸功夫"};public static StoreDaoTest m = new StoreDaoTest();static DaoHolder daoHolder = new DaoHolder();//测试保存，准备一千家店铺的数据public void testSave(){long start = System.currentTimeMillis();for( int i = 0; i < 1000; i++){double x = Math.round(Math.random() * 10000)/100.0D;double y = Math.round(Math.random() * 10000)/100.0D;Place p = new Place("Place_"+x+"_"+y,new double[]{x,y});Store s = new Store(STORE_TYPE[i%5],STORE_TYPE[i%5]+"@"+p.getName(),p);daoHolder.storeDao.save(s);}System.out.println(System.currentTimeMillis() - start);}//测试删除public void testDeleteAll(){System.out.println("Before delete the number of stores is: " + daoHolder.storeDao.count());daoHolder.storeDao.deleteAllStore();System.out.println("After delete the number of stores is: " + daoHolder.storeDao.count());}//根据地理位置查找public void testFindNearPlace(){Place p = new Place("somewhere",new double[]{23.5,67.8});System.out.println("Find 5 stores near "+ p.toString());List<Store> list = daoHolder.storeDao.findNearPlace(p);for( Store s : list)System.out.println(s.toString());System.out.println("Find 5 KFC stores near "+ p.toString());list = daoHolder.storeDao.findKFCNearPlace(p);for( Store s : list)System.out.println(s.toString());}//查找所有storepublic void testFindAll(){long start = System.currentTimeMillis();List<Store> list = daoHolder.storeDao.find().asList();for( Store s : list)System.out.println(s.toString());System.out.println(System.currentTimeMillis() - start);}static class DaoHolder{PlaceDao placeDao;StoreDao storeDao;public DaoHolder(){try {Mongo mongo = new Mongo("localhost",27017);Morphia morphia = new Morphia();Datastore ds = morphia.createDatastore(mongo, "testDB");placeDao = new PlaceDao(ds);storeDao = new StoreDao(ds);} catch (Exception e) {e.printStackTrace();}}}}

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????首先， 通过调用StoreDaoTest.m.testSave()保存一千家店铺，用来做数据准备。

???? 其次，通过调用StoreDaoTest.m.testFindAll()查看数据是否ok，当然也可以通过shell窗口查看。

???? 现在可以通过?StoreDaoTest.m.testFindNearPlace()来查找地方p附近的相关店铺了，在这个方法中，我查了两次，一次是查找离p[loc=[23.5, 67.8], name=somewhere]最近的任意五个店铺，dao中这样写：

ds.createQuery(Store.class).field("place.loc").near(p.getLoc()[0], p.getLoc()[1]).limit(5).asList();

第二次是查找离p[loc=[23.5, 67.8], name=somewhere]最近的五个肯德基店铺，dao中这样写：

ds.createQuery(Store.class).filter("name", "肯德基")

.field("place.loc").near(p.getLoc()[0], p.getLoc()[1]).limit(5).asList();

输出结果：

Find 5 stores near Place [loc=[23.5, 67.8], name=somewhere]
Store [desc=麦当劳@Place_24.42_67.77, id=4ef9cc2cec9dcb16b1b552d2, name=麦当劳, place=Place [loc=[24.42, 67.77], name=Place_24.42_67.77]]
Store [desc=蒸功夫@Place_24.32_70.0, id=4ef9cc2dec9dcb16b1b553b6, name=蒸功夫, place=Place [loc=[24.32, 70.0], name=Place_24.32_70.0]]
Store [desc=必胜客@Place_24.08_64.89, id=4ef9cc2dec9dcb16b1b5544f, name=必胜客, place=Place [loc=[24.08, 64.89], name=Place_24.08_64.89]]
Store [desc=肯德基@Place_21.05_65.88, id=4ef9cc2dec9dcb16b1b5539e, name=肯德基, place=Place [loc=[21.05, 65.88], name=Place_21.05_65.88]]
Store [desc=吉野家@Place_25.78_65.66, id=4ef9cc2cec9dcb16b1b551f3, name=吉野家, place=Place [loc=[25.78, 65.66], name=Place_25.78_65.66]]
Find 5 KFC stores near Place [loc=[23.5, 67.8], name=somewhere]
Store [desc=肯德基@Place_21.05_65.88, id=4ef9cc2dec9dcb16b1b5539e, name=肯德基, place=Place [loc=[21.05, 65.88], name=Place_21.05_65.88]]
Store [desc=肯德基@Place_21.13_74.42, id=4ef9cc2dec9dcb16b1b5550b, name=肯德基, place=Place [loc=[21.13, 74.42], name=Place_21.13_74.42]]
Store [desc=肯德基@Place_20.26_77.73, id=4ef9cc2cec9dcb16b1b55204, name=肯德基, place=Place [loc=[20.26, 77.73], name=Place_20.26_77.73]]
Store [desc=肯德基@Place_32.55_73.14, id=4ef9cc2cec9dcb16b1b552ae, name=肯德基, place=Place [loc=[32.55, 73.14], name=Place_32.55_73.14]]
Store [desc=肯德基@Place_19.01_77.68, id=4ef9cc2cec9dcb16b1b55209, name=肯德基, place=Place [loc=[19.01, 77.68], name=Place_19.01_77.68]]

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???? 最后当然也可以通过StoreDaoTest.m.testDeleteAll() 删除所有测试数据。例子很简单，是我这个礼拜学习的一个小结吧，不罗嗦了。当然很多mongodb的操作命令就不记录了，有用到了再查吧，接下来会去学习一下spring data整合mongodb。

1 楼 thaIm 2011-12-28 写的蛮有条理，学习ing~~