Sono disponibili altri esempi per SDK AWS nel repository GitHub della documentazione degli esempi per SDK AWS.
Esempi di codice per DynamoDB con SDK AWS
Gli esempi di codice seguenti mostrano come utilizzare Amazon DynamoDB con un Software Development Kit (SDK) AWS.
Nozioni di base: esempi di codice che mostrano come eseguire le operazioni essenziali all’interno di un servizio.
Le azioni sono estratti di codice da programmi più grandi e devono essere eseguite nel contesto. Sebbene le operazioni mostrino come richiamare le singole funzioni del servizio, è possibile visualizzarle contestualizzate negli scenari correlati.
Scenari: esempi di codice che mostrano come eseguire un’attività specifica chiamando più funzioni all’interno dello stesso servizio o combinate con altri Servizi AWS.
I contributi della community AWS sono esempi creati e gestiti da più team AWS. Per fornire un feedback, utilizza il meccanismo disponibile nei repository collegati.
Nozioni di base
Gli esempi di codice seguenti mostrano come iniziare a utilizzare DynamoDB.
- .NET
-
- SDK per .NET (v4)
-
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
using Microsoft.Extensions.DependencyInjection;
namespace DynamoDBActions;
/// <summary>
/// A simple example that demonstrates basic DynamoDB operations.
/// </summary>
public class HelloDynamoDB
{
/// <summary>
/// HelloDynamoDB lists the existing DynamoDB tables for the default user.
/// </summary>
/// <param name="args">Command line arguments</param>
/// <returns>Async task.</returns>
static async Task Main(string[] args)
{
// Set up dependency injection for Amazon DynamoDB.
using var host = Microsoft.Extensions.Hosting.Host.CreateDefaultBuilder(args)
.ConfigureServices((_, services) =>
services.AddAWSService<IAmazonDynamoDB>()
)
.Build();
// Now the client is available for injection.
var dynamoDbClient = host.Services.GetRequiredService<IAmazonDynamoDB>();
try
{
var request = new ListTablesRequest();
var tableNames = new List<string>();
var paginatorForTables = dynamoDbClient.Paginators.ListTables(request);
await foreach (var tableName in paginatorForTables.TableNames)
{
tableNames.Add(tableName);
}
Console.WriteLine("Welcome to the DynamoDB Hello Service example. " +
"\nLet's list your DynamoDB tables:");
tableNames.ForEach(table =>
{
Console.WriteLine($"Table: {table}");
});
}
catch (AmazonDynamoDBException ex)
{
Console.WriteLine($"An Amazon DynamoDB service error occurred while listing tables. {ex.Message}");
}
catch (Exception ex)
{
Console.WriteLine($"An error occurred while listing tables. {ex.Message}");
}
}
}
- C++
-
- SDK per C++
-
Codice per il file CMake CMakeLists.txt.
# Set the minimum required version of CMake for this project.
cmake_minimum_required(VERSION 3.13)
# Set the AWS service components used by this project.
set(SERVICE_COMPONENTS dynamodb)
# Set this project's name.
project("hello_dynamodb")
# Set the C++ standard to use to build this target.
# At least C++ 11 is required for the AWS SDK for C++.
set(CMAKE_CXX_STANDARD 11)
# Use the MSVC variable to determine if this is a Windows build.
set(WINDOWS_BUILD ${MSVC})
if (WINDOWS_BUILD) # Set the location where CMake can find the installed libraries for the AWS SDK.
string(REPLACE ";" "/aws-cpp-sdk-all;" SYSTEM_MODULE_PATH "${CMAKE_SYSTEM_PREFIX_PATH}/aws-cpp-sdk-all")
list(APPEND CMAKE_PREFIX_PATH ${SYSTEM_MODULE_PATH})
endif ()
# Find the AWS SDK for C++ package.
find_package(AWSSDK REQUIRED COMPONENTS ${SERVICE_COMPONENTS})
if (WINDOWS_BUILD AND AWSSDK_INSTALL_AS_SHARED_LIBS)
# Copy relevant AWS SDK for C++ libraries into the current binary directory for running and debugging.
# set(BIN_SUB_DIR "/Debug") # if you are building from the command line you may need to uncomment this
# and set the proper subdirectory to the executables' location.
AWSSDK_CPY_DYN_LIBS(SERVICE_COMPONENTS "" ${CMAKE_CURRENT_BINARY_DIR}${BIN_SUB_DIR})
endif ()
add_executable(${PROJECT_NAME}
hello_dynamodb.cpp)
target_link_libraries(${PROJECT_NAME}
${AWSSDK_LINK_LIBRARIES})
Codice per il file origine hello_dynamodb.cpp.
#include <aws/core/Aws.h>
#include <aws/dynamodb/DynamoDBClient.h>
#include <aws/dynamodb/model/ListTablesRequest.h>
#include <iostream>
/*
* A "Hello DynamoDB" starter application which initializes an Amazon DynamoDB (DynamoDB) client and lists the
* DynamoDB tables.
*
* main function
*
* Usage: 'hello_dynamodb'
*
*/
int main(int argc, char **argv) {
Aws::SDKOptions options;
// Optionally change the log level for debugging.
// options.loggingOptions.logLevel = Utils::Logging::LogLevel::Debug;
Aws::InitAPI(options); // Should only be called once.
int result = 0;
{
Aws::Client::ClientConfiguration clientConfig;
// Optional: Set to the AWS Region (overrides config file).
// clientConfig.region = "us-east-1";
Aws::DynamoDB::DynamoDBClient dynamodbClient(clientConfig);
Aws::DynamoDB::Model::ListTablesRequest listTablesRequest;
listTablesRequest.SetLimit(50);
do {
const Aws::DynamoDB::Model::ListTablesOutcome &outcome = dynamodbClient.ListTables(
listTablesRequest);
if (!outcome.IsSuccess()) {
std::cout << "Error: " << outcome.GetError().GetMessage() << std::endl;
result = 1;
break;
}
for (const auto &tableName: outcome.GetResult().GetTableNames()) {
std::cout << tableName << std::endl;
}
listTablesRequest.SetExclusiveStartTableName(
outcome.GetResult().GetLastEvaluatedTableName());
} while (!listTablesRequest.GetExclusiveStartTableName().empty());
}
Aws::ShutdownAPI(options); // Should only be called once.
return result;
}
- Java
-
- SDK per Java 2.x
-
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.services.dynamodb.model.ListTablesRequest;
import software.amazon.awssdk.services.dynamodb.model.ListTablesResponse;
import java.util.List;
/**
* Before running this Java V2 code example, set up your development
* environment, including your credentials.
*
* For more information, see the following documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
*/
public class ListTables {
public static void main(String[] args) {
System.out.println("Listing your Amazon DynamoDB tables:\n");
Region region = Region.US_EAST_1;
DynamoDbClient ddb = DynamoDbClient.builder()
.region(region)
.build();
listAllTables(ddb);
ddb.close();
}
public static void listAllTables(DynamoDbClient ddb) {
boolean moreTables = true;
String lastName = null;
while (moreTables) {
try {
ListTablesResponse response = null;
if (lastName == null) {
ListTablesRequest request = ListTablesRequest.builder().build();
response = ddb.listTables(request);
} else {
ListTablesRequest request = ListTablesRequest.builder()
.exclusiveStartTableName(lastName).build();
response = ddb.listTables(request);
}
List<String> tableNames = response.tableNames();
if (tableNames.size() > 0) {
for (String curName : tableNames) {
System.out.format("* %s\n", curName);
}
} else {
System.out.println("No tables found!");
System.exit(0);
}
lastName = response.lastEvaluatedTableName();
if (lastName == null) {
moreTables = false;
}
} catch (DynamoDbException e) {
System.err.println(e.getMessage());
System.exit(1);
}
}
System.out.println("\nDone!");
}
}
- JavaScript
-
- SDK per JavaScript (v3)
-
Per maggiori dettagli sull’utilizzo di DynamoDB in AWS SDK per JavaScript, consulta Programming DynamoDB with JavaScript.
import { ListTablesCommand, DynamoDBClient } from "@aws-sdk/client-dynamodb";
const client = new DynamoDBClient({});
export const main = async () => {
const command = new ListTablesCommand({});
const response = await client.send(command);
console.log(response.TableNames.join("\n"));
return response;
};
- Python
-
- SDK per Python (Boto3)
-
import boto3
# Create a DynamoDB client using the default credentials and region
dynamodb = boto3.client("dynamodb")
# Initialize a paginator for the list_tables operation
paginator = dynamodb.get_paginator("list_tables")
# Create a PageIterator from the paginator
page_iterator = paginator.paginate(Limit=10)
# List the tables in the current AWS account
print("Here are the DynamoDB tables in your account:")
# Use pagination to list all tables
table_names = []
for page in page_iterator:
for table_name in page.get("TableNames", []):
print(f"- {table_name}")
table_names.append(table_name)
if not table_names:
print("You don't have any DynamoDB tables in your account.")
else:
print(f"\nFound {len(table_names)} tables.")
- Ruby
-
- SDK per Ruby
-
require 'aws-sdk-dynamodb'
require 'logger'
# DynamoDBManager is a class responsible for managing DynamoDB operations
# such as listing all tables in the current AWS account.
class DynamoDBManager
def initialize(client)
@client = client
@logger = Logger.new($stdout)
end
# Lists and prints all DynamoDB tables in the current AWS account.
def list_tables
@logger.info('Here are the DynamoDB tables in your account:')
paginator = @client.list_tables(limit: 10)
table_names = []
paginator.each_page do |page|
page.table_names.each do |table_name|
@logger.info("- #{table_name}")
table_names << table_name
end
end
if table_names.empty?
@logger.info("You don't have any DynamoDB tables in your account.")
else
@logger.info("\nFound #{table_names.length} tables.")
end
end
end
if $PROGRAM_NAME == __FILE__
dynamodb_client = Aws::DynamoDB::Client.new
manager = DynamoDBManager.new(dynamodb_client)
manager.list_tables
end
