cosmos DB概述及使用

1、优势
1)吞吐量和 存储可弹性缩放
2)低延迟
3)多模型,多API
4)无需架构和索引管理
5)静态和动态加密

2、使用
2.1、查询数据

select * from c where c.id = ‘’

2.2、 使用同步(Sync)API管理数据库资源
1)CosmosClient初始化.

client = new CosmosClientBuilder()
            .endpoint(AccountSettings.HOST)
            .key(AccountSettings.MASTER_KEY)
            //  Setting the preferred location to Cosmos DB Account region
            //  West US is just an example. User should set preferred location to the Cosmos DB region closest to the application
            .preferredRegions(Collections.singletonList("China East 2"))
            .consistencyLevel(ConsistencyLevel.EVENTUAL)
            .buildClient();

2)CosmosDatabase的创建

//  Create database if not exists
        //  
        CosmosDatabaseResponse cosmosDatabaseResponse = client.createDatabaseIfNotExists(databaseName);
        database = client.getDatabase(cosmosDatabaseResponse.getProperties().getId());

3)CosmosContainer的创建

 //  Create container if not exists
        //  
        CosmosContainerProperties containerProperties =
            new CosmosContainerProperties(containerName, "/lastName");

        //  Create container with 400 RU/s
        CosmosContainerResponse cosmosContainerResponse =
            database.createContainerIfNotExists(containerProperties, ThroughputProperties.createManualThroughput(400));
        container = database.getContainer(cosmosContainerResponse.getProperties().getId());

4)使用createItem方法创建项

//  Create item using container that we created using sync client

            //  Use lastName as partitionKey for cosmos item
            //  Using appropriate partition key improves the performance of database operations
            CosmosItemRequestOptions cosmosItemRequestOptions = new CosmosItemRequestOptions();
            CosmosItemResponse<Family> item = container.createItem(family, new PartitionKey(family.getLastName()), cosmosItemRequestOptions);
          

5、使用queryItems方法对JSON执行SQL查询

// Set some common query options
        CosmosQueryRequestOptions queryOptions = new CosmosQueryRequestOptions();
        //queryOptions.setEnableCrossPartitionQuery(true); //No longer necessary in SDK v4
        //  Set query metrics enabled to get metrics around query executions
        queryOptions.setQueryMetricsEnabled(true);

        CosmosPagedIterable<Family> familiesPagedIterable = container.queryItems(
            "SELECT * FROM Family WHERE Family.lastName IN ('Andersen', 'Wakefield', 'Johnson')", queryOptions, Family.class);

        familiesPagedIterable.iterableByPage(10).forEach(cosmosItemPropertiesFeedResponse -> {
            logger.info("Got a page of query result with {} items(s) and request charge of {}",
                    cosmosItemPropertiesFeedResponse.getResults().size(), cosmosItemPropertiesFeedResponse.getRequestCharge());

            logger.info("Item Ids {}", cosmosItemPropertiesFeedResponse
                .getResults()
                .stream()
                .map(Family::getId)
                .collect(Collectors.toList()));
        });

7)使用readItem方法执行点读取

familiesToCreate.forEach(family -> {
            //  
            try {
                CosmosItemResponse<Family> item = container.readItem(family.getId(), new PartitionKey(family.getLastName()), Family.class);
                double requestCharge = item.getRequestCharge();
                Duration requestLatency = item.getDuration();
                logger.info("Item successfully read with id {} with a charge of {} and within duration {}",
                    item.getItem().getId(), requestCharge, requestLatency);
            } catch (CosmosException e) {
                logger.error("Read Item failed with", e);
            }