NoSQL 之 Morphia 操作 MongoDB

野性酷女 2022-06-06 01:07 211阅读 0赞

#### 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][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][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][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][https_github.com_mongodb_mongo-java-driver]

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

[![clip\_image002][clip_image002]][clip_image002_clip_image002]

#### 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][Link 1]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

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

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

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

@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

//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

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

@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

@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

@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

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

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

@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

@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

@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();

}

[https_github.com_mongodb_mongo-java-driver_downloads]: https://github.com/mongodb/mongo-java-driver/downloads
[http_www.mongodb.org_display_DOCS_Java_Language_Center]: http://www.mongodb.org/display/DOCS/Java+Language+Center
[https_download.github.com_mongodb-mongo-java-driver-r2.6.1-7-g6037357.zip]: https://download.github.com/mongodb-mongo-java-driver-r2.6.1-7-g6037357.zip
[https_github.com_mongodb_mongo-java-driver]: https://github.com/mongodb/mongo-java-driver
[http_code.google.com_p_morphia_downloads_list]: http://code.google.com/p/morphia/downloads/list
[clip_image002]: http://images.cnblogs.com/cnblogs_com/hoojo/201202/201202171024334656.jpg
[clip_image002_clip_image002]: /images/20220606/ea1fffeb3dc24af6b43b90bb24cafc6b.png
[Link 1]: http://www.cnblogs.com/hoojo/archive/2011/06/01/2066426.html