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();
    }