访问DataBase

当已经有一个初始化好的MongoClient后，通过如下方式来访问一个database，示例如下：

MongoDatabase memberInfoDatabase = mongoClient.getDatabase("MemberInfo");

访问集合

当获取一个MongoDatabase实例后，可以通过如下命令来得到要获取的集合：

MongoCollection<Document> coll = memberInfoDatabase.getCollection("gold_member");

显示的创建一个集合

也可以通过 createCollection()方法显示的创建一个集合，并在创建时候指定该集合的属性。

memberInfoDatabase.createCollection("testCollection", new CreateCollectionOptions().sizeInBytes(200000));

插入数据

Document doc0 = new Document("name", "万三")
        .append("age", 30)
        .append("sex", "male");
​
Document doc1 = new Document("name", "刘亚")
        .append("age", 42)
        .append("sex", "male");
​
Document doc2 = new Document("name", "王莹")
        .append("age", 22)
        .append("sex", "female");
​
List<Document> documents = new ArrayList<>();
documents.add(doc0);
documents.add(doc1);
documents.add(doc2);
goldMemberCollection.insertMany(documents);

删除数据

goldMemberCollection.deleteOne(eq("name", "刘亚"));

删除表

MongoCollection<Document> collection = memberInfoDatabase.getCollection("test");
collection.drop();

读数据

MongoCursor<String> cursor = (MongoCursor<String>) goldMemberCollection.find();
while (cursor.hasNext())  {
    Object result = cursor.next();
}
cursor.close();

带过滤条件的查询

MongoCursor<String> cursorCondition = (MongoCursor<String>)goldMemberCollection.find(
        new Document("name","zhangsan")
                .append("age", 5));
while (cursorCondition.hasNext())  {
    Object result = cursorCondition.next();
}
cursorCondition.close();

运行命令

执行buildInfo和collStats：

MongoClient mongoClientShell = (MongoClient) MongoClients.create();
MongoDatabase database = mongoClientShell.getDatabase("MemberInfo");
​
Document buildInfoResults = database.runCommand(new Document("buildInfo", 1));
System.out.println(buildInfoResults.toJson());
​
Document collStatsResults = database.runCommand(new Document("collStats", "restaurants"));
System.out.println(collStatsResults.toJson());

创建索引

MongoCollection<Document> collectionTest = memberInfoDatabase.getCollection("gold_member");
collectionTest.createIndex(Indexes.ascending("age"));