mongo morphia

ling3 · 发表于 2015-11-11 09:24:50

NoSQL 之 Morphia 操作 MongoDB2012-02-17 13:49:26 我来说两句收藏

我要投稿上文章 http://www.iyunv/database/201202/119911.html

介绍到了在MongoDB的控制台完成MongoDB的数据操作、以及通过Java MongoDB 的驱动完成在Java中对MongoDB的操作，通过前两篇文章我们对MongoDB有了全面、深刻的认识和理解。现在我们就看看利用Morphia库来操作MongoDB。

开发环境：

System：Windows

IDE：eclipse、MyEclipse 8

Database：mongoDB

开发依赖库：

JavaEE5、mongo-2.5.3.jar、junit-4.8.2.jar, morphia-0.99.jar

Email：hoojo_@126.com

Blog：http://blog.iyunv.com/IBM_hoojo

http://hoojo.cnblogs.com/

一、准备工作
1、首先，下载mongoDB对Java支持的驱动包

驱动包下载地址：https://github.com/mongodb/mongo-java-driver/downloads

mongoDB对Java的相关支持、技术：http://www.mongodb.org/display/DOCS/Java+Language+Center

驱动源码下载：https://download.github.com/mongodb-mongo-java-driver-r2.6.1-7-g6037357.zip

在线查看源码：https://github.com/mongodb/mongo-java-driver

Morphia jar包下载：http://code.google.com/p/morphia/downloads/list

2、下面建立一个JavaProject工程，导入下载下来的驱动包。即可在Java中使用Morphia，目录如下：

二、Java操作MongoDB示例
在本示例之前你需要启动mongod.exe的服务，在你安装mongoDB的目录中，找到mongod.exe启动服务后，下面的程序才能顺利执行；

1、Java操作mongoDB数据库，操作索引

Mongo mongo = new Mongo();

这样就创建了一个MongoDB的数据库连接对象，它默认连接到当前机器的localhost地址，端口是27017。

DB db = mongo.getDB(“test”);

这样就获得了一个test的数据库，如果mongoDB中没有创建这个数据库也是可以正常运行的。如果你读过上一篇文章就知道，mongoDB可以在没有创建这个数据库的情况下，完成数据的添加操作。当添加的时候，没有这个库，mongoDB会自动创建当前数据库。

得到了db，下一步我们要获取一个“聚集集合DBCollection”，通过db对象的getCollection方法来完成。

DBCollection users = db.getCollection("users");

这样就获得了一个DBCollection，它相当于我们数据库的“表”。

查询所有数据

DBCursor cur = users.find();

while (cur.hasNext()) {

System.out.println(cur.next());

}

用BasicDBObjectBuilder，向users对象中添加数据

user = BasicDBObjectBuilder.start("id", 1546555)

.append("name", "jojo").add("address", "gz")

.append("email", "hoojo_@126.com")

.get();

插入数据

users.insert(user);

可以利用JSON工具来序列化对象数据

JSON.serialize(cur)

完整源码

package com.hoo.test;

import java.net.UnknownHostException;
import com.hoo.entity.User;
import com.hoo.util.BasicDBObjectUtils;
import com.mongodb.BasicDBObjectBuilder;
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.util.JSON;

/**
* function: Mongo实例对象的相关方法测试
* @author hoojo
* @createDate 2011-5-24 下午02:42:29
* @file MongoDBTest.java
* @package com.hoo.test
* @project MongoDB
* @blog http://blog.iyunv.com/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
public class MongoDBTest {

public static void main(String[] args) throws UnknownHostException, MongoException {
 Mongo mg = new Mongo();

 System.out.println("查询所有的Database的名称");
 for (String name : mg.getDatabaseNames()) {
 System.out.println("dbName: " + name);
 }

 System.out.println("查询test库中的所有collection集合（表）名称");
 DB db = mg.getDB("test");
 for (String name : db.getCollectionNames()) {
 System.out.println("collectionName: " + name);
 }

 System.out.println("添加测试数据");
 DBCollection users = db.getCollection("users");
 try {
 // 用自定义BasicDBObjectUtils工具类，将User Enity对象转换成DBObject
 DBObject user = BasicDBObjectUtils.castModel2DBObject(new User("345567", "jack", 22, "beijin"));
 users.insert(user);
 // 用BasicDBObjectBuilder构建一个DBObject对象
 user = BasicDBObjectBuilder.start("id", 1546555).append("name", "jojo").add("address", "gz").append("email", "hoojo_@126.com").get();
 users.insert(user);
 } catch (Exception e) {
 e.printStackTrace();
 }

 System.out.println("游标查询所有users集合数据");
 DBCursor cur = users.find();
 while (cur.hasNext()) {
 System.out.println(cur.next());
 }
 System.out.println("查询游标相关内容");
 System.out.println(cur.count());
 System.out.println(cur.getCursorId());
 System.out.println(cur.getOptions());
 System.out.println(cur.getQuery());
 System.out.println(cur.getSizes().listIterator());

 System.out.println(cur.itcount());
 //System.out.println(cur.length());
 System.out.println(cur.size());
 System.out.println(cur.numGetMores());
 System.out.println(cur.curr());
 //System.out.println(cur.toArray().get(0));

 System.out.println("显示游标查询到的所有内容：" + JSON.serialize(cur));
}
}

工具类，将带有getter、setter方法的Java类序列化成DBObject对象

package com.hoo.util;

import java.lang.reflect.Method;
import com.mongodb.BasicDBObject;
import com.mongodb.DBObject;

/**
* function: 将Entity/Model转换成DBObject
* @author hoojo
* @createDate 2011-5-30下午01:53:08
* @file BasicDBObjectUtil.java
* @package com.hoo.util
* @project MongoDB
* @blog http://blog.iyunv.com/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
publicclass BasicDBObjectUtils {
public static<T> DBObject castModel2DBObject(T entity) throws Exception {
 Method[] method = entity.getClass().getMethods();

 DBObject dbObject = new BasicDBObject();
 for (Method m : method) {
 //System.out.println(m.getName());
 if (m.getName().startsWith("get")) {
 String name = m.getName().replace("get", "");
 for (Method m2 : method) {
 if (m2.getName().equals("set" + name)) {
 name = name.substring(0, 1).toLowerCase() + name.substring(1);
 Object returnVal = m.invoke(entity, new Object[] {});
 if (returnVal != null) {
 //System.out.println(name + " : " + m.invoke(shipping, new Object[] {}));
 dbObject.put(name, returnVal);
 }
 }
 }
 }
 }
 System.out.println("dbObject: " + dbObject);
 return dbObject;
}
}

2、完成索引操作，首先建立一个MongoDB4IndexTest.java，基本测试代码如下：

package com.hoo.test;

import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import org.bson.types.ObjectId;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.mongodb.BasicDBObject;
import com.mongodb.Bytes;
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.QueryOperators;
import com.mongodb.util.JSON;

/**
* function: 实现MongoDB的Index操作
* @author hoojo
* @createDate 2011-6-2 下午03:21:23
* @file MongoDB4IndexTest.java
* @package com.hoo.test
* @project MongoDB
* @blog http://blog.iyunv.com/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
public class MongoDB4IndexTest {

private Mongo mg = null;
private DB db;
private DBCollection users;

@Before
public void init() {
 try {
 mg = new Mongo();
 //mg = new Mongo("localhost", 27017);
 } catch (UnknownHostException e) {
 e.printStackTrace();
 } catch (MongoException e) {
 e.printStackTrace();
 }
 //获取temp DB；如果默认没有创建，mongodb会自动创建
 db = mg.getDB("temp");
 //获取users DBCollection；如果默认没有创建，mongodb会自动创建
 users = db.getCollection("users");
}

@After
public void destory() {
 if (mg != null)
 mg.close();
 mg = null;
 db = null;
 users = null;
 System.gc();
}

public void print(Object o) {
 System.out.println(o);
}
}

3、下面完成对象Collection的index的操作

/**
* function: 测试Collection的index相关操作
* @author hoojo
* @createDate 2012-2-16 下午08:32:26
*/
@Test
public void testIndex() {
query();

for (DBObject index : coll.getIndexInfo()) {
 print("IndexInfo: " + index);
}

coll.dropIndexes();
//创建索引
coll.createIndex(new BasicDBObject("name", "idx_name"));
print(coll.findOne(new BasicDBObject("name", "haha")));
coll.createIndex(coll.findOne(new BasicDBObject("name", "haha")));
DBObject o = new BasicDBObject("unique", true);
//coll.createIndex(coll.findOne(), o);

// 修改索引，如果存在就修改不存在就添加
coll.ensureIndex(o);
coll.ensureIndex("age_1");
coll.ensureIndex(new BasicDBObject("age3_1", 6), new BasicDBObject("ts", -1));
coll.ensureIndex(new BasicDBObject("age_2", 1), new BasicDBObject( "ts" , 1 ));
coll.ensureIndex(new BasicDBObject("password", 2), new BasicDBObject( "z" , "idx" ));
coll.ensureIndex(new BasicDBObject("password", 1), new BasicDBObject( "etc" , "idx" ));
// 创建唯一索引
coll.ensureIndex(new BasicDBObject("emial", 2), new BasicDBObject("unique", false));
// 创建索引，指定索引名称default_index
coll.ensureIndex(new BasicDBObject("address", 1), new BasicDBObject( "name" , "default_index"));
// 创建索引对象，索引名称user_index
coll.ensureIndex(coll.findOne(new BasicDBObject("name", "hoho")), "user_index");
// 唯一索引
coll.ensureIndex(coll.findOne(new BasicDBObject("name", "hehe")), "users_index_unique", true);

// 查询所有索引
for (DBObject index : coll.getIndexInfo()) {
 print("IndexInfo: " + index);
}

print(DBCollection.genIndexName(coll.findOne()));

//coll.dropIndex(coll.findOne());
print(DBCollection.genIndexName(new BasicDBObject("password", 2)));
//coll.dropIndex(DBCollection.genIndexName(new BasicDBObject("password", 2)));
//coll.dropIndexes();
//coll.dropIndexes("assword_1");
}

三、Morphia基本操作
1、morphia可以利用annotation对JavaEntity进行注解，那样我们就可以用morphia操作JavaEntity对象

package com.hoo.entity;

import com.google.code.morphia.annotations.Entity;
import com.google.code.morphia.annotations.Id;

/**
* function: JavaEntity对象
* @author hoojo
* @createDate 2011-5-31上午11:45:21
* @file User.java
* @package com.hoo.entity
* @project Morphia
* @blog http://blog.iyunv.com/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
//利用morphia的annotation进行注解
@Entity
public class User {
@Id
private long id;

private String name;
private boolean sex;
private int age;
private String address;

public User() {
}
public User(long id, String name, boolean sex, int age, String address) {
 super();
 this.id = id;
 this.name = name;
 this.sex = sex;
 this.age = age;
 this.address = address;
}
//getter、setter

@Override
public String toString() {
 return this.id + "#" + this.name + "#" + this.age + "#" + this.sex + "#" + this.address;
}
}

2、对Morphia对象一些简单的使用，看看该对象提供了哪些基本的操作方法

package com.hoo.test.morphia;

import java.net.UnknownHostException;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.google.code.morphia.Datastore;
import com.google.code.morphia.EntityInterceptor;
import com.google.code.morphia.Morphia;
import com.google.code.morphia.mapping.MappedClass;
import com.google.code.morphia.mapping.Mapper;
import com.google.code.morphia.mapping.cache.EntityCache;
import com.hoo.entity.User;
import com.mongodb.BasicDBObjectBuilder;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

/**
* function: morphia对象的简单测试
* @author hoojo
* @createDate 2011-5-31上午11:30:20
* @file MorphiaTest.java
* @package com.hoo.test
* @project Morphia
* @blog http://blog.iyunv.com/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
public class MorphiaTest {
private Mongo mongo;
private Morphia morphia;

@Before
public void init() {
 try {
 mongo = new Mongo();
 } catch (UnknownHostException e) {
 e.printStackTrace();
 } catch (MongoException e) {
 e.printStackTrace();
 }
 morphia = new Morphia();
}

private void print(Object o) {
 if (o != null) {
 System.out.println(o.toString());
 }
}

/**
 * function: morphia对象的简单测试
 * @author hoojo
 */
@SuppressWarnings("deprecation")
@Test
public void testMorphia() {
 // 创建一个Datastore，过时的方法不推荐使用
 Datastore ds = morphia.createDatastore("myTestDB");
 print("createDatastore: " + ds);
 // 创建ds
 ds = morphia.createDatastore(mongo, "myTestDB");
 print("createDatastore: " + ds);
 // 创建一个带用户名、密码的ds
 //ds = morphia.createDatastore(mongo, "myTestDB", "admin", new char[] { '1', '2', '3', '4', '5', '6' });

 // 设置操作资源对象，这里设置User.class 就可以完成对User的一系列操作
 //morphia.map(User.class);
 //morphia.mapPackage("com.hoo.entity");//会把整个包下面的类都加载进来
 // 将对象转成DBObject
 print("toDBObject: " + morphia.toDBObject(new User(System.currentTimeMillis(), "jackson", true, 22, null)));
 // 将参数2转换成参数1的类型
 print("fromDBObject: " + morphia.fromDBObject(User.class, BasicDBObjectBuilder.start("sex", true).get()));
 print("getMapper: " + morphia.getMapper());
 print("isMapped: " + morphia.isMapped(User.class));

}

/**
 * function: 对Mapper对象相关操作
 * @author hoojo
 * @createDate 2012-2-16下午10:20:38
 */
@Test
public void testMapper() {
 Mapper mapper = morphia.getMapper();
 // 添加对象映射
 print("addMappedClass: " + mapper.addMappedClass(User.class));
 //print(mapper.addMappedClass(mapper.addMappedClass(User.class));

 // 创建实体缓存
 print("createEntityCache: " + mapper.createEntityCache());
 print(mapper.getCollectionName("myTestDB"));
 print(mapper.getConverters());
 User user = new User(System.currentTimeMillis(), "jackson", true, 22, null);
 user.setId(1306814012734L);
 print(mapper.getId(user));

 for (EntityInterceptor ei : mapper.getInterceptors()) {
 System.out.println("EntityInterceptor: " + ei);
 }

 // 查询主键
 print("getKey: " + mapper.getKey(user));
 // 所有已经映射的class
 for (MappedClass mc : mapper.getMappedClasses()) {
 System.out.println("getMappedClasses: " + mc);
 }

 print("mcMap: " + mapper.getMCMap());

 print("getOptions: " + mapper.getOptions());
 print("keyToRef: " + mapper.keyToRef(mapper.getKey(user)));
 print("refToKey: " + mapper.refToKey(mapper.keyToRef(mapper.getKey(user))));
}

/**
 * function: 实体缓存
 * @author hoojo
 */
@Test
public void testEntityCache() {
 EntityCache ec = morphia.getMapper().createEntityCache();
 print("EntityCache: " + ec);
 Datastore ds = morphia.createDatastore(mongo, "myTestDB");
 User user = new User(System.currentTimeMillis(), "jackson", true, 22, null);
 user.setId(1306814012734L);

 // 添加实体
 ec.putEntity(ds.getKey(user), user);
 // 代理
 ec.putProxy(ds.getKey(user), user);

 print("getKey: " + ds.getKey(user));
 print("getProxy: " + ec.getProxy(ds.getKey(user)));
 print("getEntity: " + ec.getEntity(ds.getKey(user)));

 print(ec.exists(ds.getKey(user)));

 print("stats: " + ec.stats());
}

@After
public void destory() {
 mongo = null;
 morphia = null;
 System.gc();
}
}

四、利用Morphia完成对Datastore对象的CRUD操作
1、首先添加如下准备代码，随后的方法直接添加到该文件中即可

package com.hoo.test.ds;

import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.google.code.morphia.Datastore;
import com.google.code.morphia.Key;
import com.google.code.morphia.Morphia;
import com.google.code.morphia.query.UpdateOperations;
import com.hoo.entity.User;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

/**
* function: Datastore增删改查操作
* @author hoojo
* @createDate 2011-5-31下午06:29:04
* @fileDatastore DatastoreTest.java
* @package com.hoo.test.ds
* @project Morphia
* @blog http://blog.iyunv.com/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
public class DatastoreTest {
private Mongo mongo;
private Morphia morphia;
private Datastore ds;

@Before
public void init() {
 try {
 mongo = new Mongo();
 } catch (UnknownHostException e) {
 e.printStackTrace();
 } catch (MongoException e) {
 e.printStackTrace();
 }
 morphia = new Morphia();
 morphia.map(User.class);
 ds = morphia.createDatastore(mongo, "temp");
}

private void print(Object o) {
 if (o != null) {
 System.out.println(o.toString());
 }
}

/**
* function: 查询所有
* @author hoojo
* @createDate 2012-2-16 下午10:36:13
*/
private void query() {
 Iterable<User> it = ds.createQuery(User.class).fetch();
 while(it.iterator().hasNext()) {
 print("fetch: " + it.iterator().next());
 }
}

@After
public void destory() {
 mongo = null;
 morphia = null;
 ds = null;
 System.gc();
}
}

2、增删改CUD操作

/**
* function: CUD增删改
* @author hoojo
* @createDate 2012-2-16 下午10:46:08
*/
@Test
public void testCUD() {
// 添加测试数据
for (int i = 0; i < 50; i++) {
 User u = new User(System.currentTimeMillis() + i, "test-" + i, ((i % 2 == 0)? true: false), 18 + i, "china-gz#" + i);
 print(ds.save(u));
}
//ds.delete(ds.createQuery(User.class));

List<User> users = new ArrayList<User>();
users.add(new User(1306907246518L, "zhangsan", true, 22, "china-gz"));
User user = new User(System.currentTimeMillis() + 3, "zhaoliu", true, 29, "china-beijin");
users.add(user);
users.add(new User(System.currentTimeMillis() + 6, "wangwu", true, 24, "china-shanghai"));
users.add(new User(System.currentTimeMillis() + 9, "lisi", true, 26, "china-wuhan"));
//添加集合
print("save: " + ds.save(users));

//添加数组
print("save: " + ds.save(users.toArray()));

this.query();
print("getKey: " + ds.find(User.class, "id", 1306907246518L).getKey());

//修改操作
UpdateOperations<User> uo = ds.createUpdateOperations(User.class);

print("update: " + ds.update(ds.find(User.class, "id", 1306907246518L).getKey(), uo).getUpdatedCount());
uo.add("name", "zhaoliuliu").set("age", 29).set("sex", true).add("address", "gzz");
print("update: " + ds.update(ds.find(User.class, "id", 1306907246518L).getKey(), uo).getUpdatedCount());

print("update: " + ds.update(ds.createQuery(User.class).field("id").equal(1306907246518L), uo).getUpdatedCount());
print("update: " + ds.update(ds.find(User.class, "id", 1306907246518L), uo).getUpdatedCount());

uo = ds.createUpdateOperations(User.class);
uo.set("name", "zhaoqq").set("age", 29).set("sex", true).add("address", "fzz");
print("update: " + ds.update(ds.find(User.class, "id", 1306907246518L).get(), uo).getUpdatedCount());

print("update: " + ds.update(ds.createQuery(User.class).field("id").equal(1306907246518L), uo, true).getUpdatedCount());

// 修改第一个对象
print("updateFirst: " + ds.updateFirst(ds.createQuery(User.class).field("id").equal(1306907246518L), uo).getUpdatedCount());
//当参数createIfMissing为true的时候，如果修改的对象不存在就会添加这条数据，如果为false的情况下，不存在也不添加
print("updateFirst: " + ds.updateFirst(ds.createQuery(User.class).field("id").equal(1306907246519L), uo, true).getUpdatedCount());
user.setId(1306907246518L);
print("updateFirst: " + ds.updateFirst(ds.createQuery(User.class).field("id").equal(1306907246518L), user, true).getUpdatedCount());

user.setId(1306916670518L);
// 合并
print("merge: " + ds.merge(user).getId());
this.query();

//删除
print("delete: " + ds.delete(ds.createQuery(User.class).field("id").equal(1306907246518L)).getN());
print("delete: " + ds.delete(ds.find(User.class, "age", 29).get()).getN());
//print("delete: " + ds.delete(User.class, 1306911594631L).getN());
//print("delete: " + ds.delete(User.class, users).getN());
//ds.delete(ds.createQuery(User.class));
this.query();
}

3、Find查询操作

/**
* function: find查询
* @author hoojo
* @createDate 2012-2-16 下午10:45:55
*/
@Test
public void testFind() {
print("find: " + ds.find(User.class).asList());
//like
print("find-contains: " + ds.find(User.class).field("name").contains("test-1").asList());
//忽略大小写
print("find-containsIgnoreCase: " + ds.find(User.class).field("name").containsIgnoreCase("ja").asList());

print("find-endsWith: " + ds.find(User.class).field("name").endsWith("22").asList());
print("find-endsWithIgnoreCase: " + ds.find(User.class).field("name").endsWithIgnoreCase("CK").asList());

//过滤null或是没有name属性的
print("find-doesNotExist: " + ds.find(User.class).field("name").doesNotExist().asList());
//查询name有值的数据
print("find-doesNotExist: " + ds.find(User.class).field("name").exists().asList());
//age > 48
print("find-greaterThan: " + ds.find(User.class).field("age").greaterThan(66).asList());
//age >= 48
print("find-greaterThan: " + ds.find(User.class).field("age").greaterThanOrEq(66).asList());

List<Integer> ageList = new ArrayList<Integer>();
ageList.add(22);
ageList.add(55);
ageList.add(66);
//all
print("find-hasAllOf: " + ds.find(User.class).field("age").hasAllOf(ageList).asList());
//in
print("find-hasAnyOf: " + ds.find(User.class).field("age").hasAnyOf(ageList).asList());
//not in
print("find-hasNoneOf: " + ds.find(User.class).field("age").hasNoneOf(ageList).asList());
//elemMatch
//print("find-hasThisElement: " + ds.find(User.class).field("age").hasThisElement(55).asList());
print("find-hasThisOne: " + ds.find(User.class).field("age").hasThisOne(55).asList());

print("find-in: " + ds.find(User.class).field("age").in(ageList).asList());
print("find-lessThan: " + ds.find(User.class).field("age").lessThan(20).asList());
print("find-lessThanOrEq: " + ds.find(User.class).field("age").lessThanOrEq(18).asList());

//print("find-lessThanOrEq: " + ds.find(User.class).field("age").near(.2, .8).asList());

print("find: " + ds.find(User.class, "id", 1306813979609L).get());
print("find: " + ds.find(User.class, "age", 28, 1, 2).asList());

print("findAndDelete: " + ds.findAndDelete(ds.createQuery(User.class).field("id").equal(1306813979609L)));
print("find: " + ds.find(User.class).asList());
}

4、Query查询操作

/**
* function: query查询
* @author hoojo
* @createDate 2012-2-16 下午10:40:10
*/
@Test
public void testQuery() {
// 查询所有
print("query: " + ds.createQuery(User.class).asList());
// 查询主键
print("query key: " + ds.createQuery(User.class).asKeyList());
// 结果集数量
print("query: " + ds.createQuery(User.class).countAll());
// 抓取查询所有记录
Iterable<User> it = ds.createQuery(User.class).fetch();
while(it.iterator().hasNext()) {
 print("fetch: " + it.iterator().next());
}

// null
it = ds.createQuery(User.class).fetchEmptyEntities();
while(it.iterator().hasNext()) {
 print("fetchEmptyEntities: " + it.iterator().next());
}

// all key
Iterable<Key<User>> itkeys = ds.createQuery(User.class).fetchKeys();
while(itkeys.iterator().hasNext()) {
 print("fetchKeys: " + itkeys.iterator().next());
}

// age > 24
print("query: " + ds.createQuery(User.class).filter("age > ", 24).asList());
// age in (20, 28)
print("query: " + ds.createQuery(User.class).filter("age in ", newint[] { 20, 28 }).asList());

// limit 3
print("query: " + ds.createQuery(User.class).limit(3).asList());
// 分页类似MySQL
print("query: " + ds.createQuery(User.class).offset(11).limit(5).asList());
// order排序，默认asc
print("query: " + ds.createQuery(User.class).order("age").asList());
//desc
print("query: " + ds.createQuery(User.class).order("-age").asList());
// 组合排序order by age, name
print("query: " + ds.createQuery(User.class).order("age, name").asList());

print("query: " + ds.createQuery(User.class).queryNonPrimary().asList());
print("query: " + ds.createQuery(User.class).queryPrimaryOnly().asList());
//如果include 为true就表示取该属性的值，其他的默认null，反之为false则该属性为null，取其他的值
print("query: " + ds.createQuery(User.class).retrievedFields(false, "age").asList());
}

5、get和count查询

/**
* function: get查询
* @author hoojo
* @createDate 2012-2-16 下午10:39:09
*/
@Test
public void testGet() {
User user = new User();
user.setId(1306916670518L);
print("get: " + ds.get(user));
List<Long> ids = new ArrayList<Long>();
ids.add(1306907246519L);
ids.add(1306916670524L);
// 通过id集合查询相当于in ()
print("get: " + ds.get(User.class, ids).asList());
// id查询
print("get: " + ds.get(User.class, 1306916670524L));
}

/**
* function: count查询
* @author hoojo
* @createDate 2012-2-16 下午10:38:02
*/
@Test
public void testGetCount() {
User user = new User();
user.setId(1306916670518L);
print("getCount: " + ds.getCount(user));
print("getCount: " + ds.getCount(User.class));

List<Long> ids = new ArrayList<Long>();
ids.add(1306907246519L);
ids.add(1306916670524L);
print("getCount: " + ds.getCount(ds.get(User.class, ids)));

// age > 22的记录
print("getCount: " + ds.getCount(ds.createQuery(User.class).filter("age > ", 22)));
// 所有
print("countAll: " + ds.get(User.class, ids).countAll());
print("countAll: " + ds.find(User.class).countAll());
}

6、其他操作

@Test
public void testOthers() {
query();
/** 索引*/
ds.ensureIndexes();
// 同时用annotation也可以给指定的属性建立索引
// 只需用在JavaEntity建立索引的属性上添加annotation
/*@Indexed(value = IndexDirection.ASC, name = "address_index")
String address;
// 建立唯一索引
@Indexed(value = IndexDirection.ASC, name = "bandName", unique = true)
String name;*/

ds.ensureCaps();
User user = new User();
user.setId(1306916670518L);
print("getDB: " + ds.getDB());
print("getDefaultWriteConcern: " + ds.getDefaultWriteConcern());
print("DBColl: " + ds.getCollection(User.class)); // 查询User对象对应的集合
Key<User> key = ds.getKey(user); // 主键
print("getKey: " + key);
print("exists: " + ds.exists(user)); //是否存在该对象
print("exists: " + ds.exists(ds.getKey(user)));

print("getByKey: " + ds.getByKey(User.class, key));
List<Key<User>> keys = new ArrayList<Key<User>>();
keys.add(key);
user.setId(1306916670521L);
keys.add(ds.getKey(user));
print("getByKey: " + ds.getByKeys(keys));
print("getByKey: " + ds.getByKeys(User.class, keys));

query();
}

用Morphia操作对象相对比较简单，它对MongoDB对Java的操作进行了一些封装，特别是查询这方面的。有没有感觉像是在用Hibernate？

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