mongodb--java操作

一、mongodb客户端

　　mongodb提供诸多语言的客户端，也包括java的客户端。通过这些客户端，我们可以很方便地使用编写代码的方式对mongodb进行操作。这里使用java客户端进行示例。使用java客户端首先需要下载jmongodb数据库java驱动。驱动的源码地址为：https://github.com/mongodb/mongo-java-driver/ 。这里工程使用maven构建，需要添加的依赖如下：

<dependency>
　　<groupId>org.mongodb</groupId>
　　<artifactId>mongo-java-driver</artifactId>
　　<version>2.12.4</version>
</dependency>

二、示例

　　1、添加文档

DB db = null;

@Before
public void getDb() throws UnknownHostException {
MongoClient mongoClient = new MongoClient();
// mongoClient = new MongoClient("localhost");
// mongoClient = new MongoClient( "localhost" , 27017 );
// mongoClient = new MongoClient(Arrays.asList(new  ServerAddress("localhost", 27017), new ServerAddress("localhost", 27018), new ServerAddress("localhost", 27019)));

//需要验证的如下
// MongoCredential credential =  MongoCredential.createMongoCRCredential(userName, database, password);
// MongoClient mongoClient = new MongoClient(new ServerAddress(),  Arrays.asList(credential));

mongoClient.setWriteConcern(WriteConcern.JOURNALED);
System.out.println("===========DatabaseName=============");
for (String s : mongoClient.getDatabaseNames()) {
System.out.println(s);
}
db = mongoClient.getDB("testdb");
}

@Test
public void addDoc() {
DBCollection coll = db.getCollection("person");
BasicDBObject doc = new BasicDBObject("name", "张三")//
.append("age", 20)//
.append("gender", "mail")//
.append("brithday", new Date())
//
.append("info",
new BasicDBObject("location_x", 203).append(
"location_y", 303));
WriteResult result = coll.insert(doc);
System.out.println(result);

for (int i = 0; i < 10; i++) {
BasicDBObject document = new BasicDBObject("name", "zhangsan" + i)//
.append("age", 18 + i)//
.append("brithday", new Date());
WriteResult result2 = coll.insert(document);
System.out.println(result2);
}

}

　　2、查询文档

@Test
public void findDoc() {
DBCollection coll = db.getCollection("person");
DBObject person = coll.findOne();// 获取集合中的第一个文档
System.out.println("===============findOne======================");
System.out.println(person);

// 根据条件查询;db.person.find({age:18});
DBObject query = new BasicDBObject("age", 18);
DBObject person2 = coll.findOne(query);
System.out.println(person2);

System.out
.println("===============findByCondtion======================");
// age小于25; db.person.find({age:{$lt:25}});
query = new BasicDBObject("age", new BasicDBObject("$lt", 25));
DBCursor cursor = coll.find(query);

try {
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
} finally {
cursor.close();
}
System.out.println("===============findAll======================");
// 查询所有并按照age升序;db.person.find().sort({age:1});
cursor = coll.find().sort(new BasicDBObject("age", -1));// 1升序,-1降序
try {
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
} finally {
cursor.close();
}
}

　　3、更新文档

@Test
public void updateDoc() {
DBCollection coll = db.getCollection("person");
BasicDBObject query = new BasicDBObject("name", "张三");
DBObject update = coll.findOne(query);
update.put("info", new BasicDBObject("location_x", 1999).append(
"location_y", 2999));
// 方法一
DBObject person = coll.findAndModify(query, update);// 返回的是未更改前的文档对象
System.out.println(person);
// 方法二
update.put("info", new BasicDBObject("location_x", 19998).append(
"location_y", 29998));
WriteResult result = coll.update(query, update);
System.out.println(result);
}

　　4、删除文档

@Test
public void deleteDoc() {
DBCollection coll = db.getCollection("person");
BasicDBObject query = new BasicDBObject("name", "zhangsan8");

// 方法一
query = new BasicDBObject("name", "zhangsan9");
DBObject person = coll.findAndRemove(query);// 返回的是删除的文档对象
System.out.println(person);

// 方法二
query = new BasicDBObject("name", "zhangsan9");
WriteResult result = coll.remove(query);
System.out.println(result);
}

　　5、集合相关操作

@Test
public void testCollection() {
Set<String> colls = db.getCollectionNames();// 数据库中的所有集合name
for (String s : colls) {
System.out.println(s);
}
System.out.println("=======================================");

// 创建一个collection,并在collection中添加document
DBCollection coll = db.createCollection("testCollection",
new BasicDBObject("capped", true).append("size", 1048576));
System.out.println(coll);

coll = db.getCollection("testCollection");

// collection中的索引
List<DBObject> list = coll.getIndexInfo();
for (DBObject o : list) {
System.out.println(o);
}

coll.drop();
}