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Esempi di codice per l'utilizzo di DynamoDB AWS SDKs
I seguenti esempi di codice mostrano come utilizzare DynamoDB con AWS un kit di sviluppo software (). SDK
Le basi sono esempi di codice che mostrano come eseguire le operazioni essenziali all'interno di un servizio.
Le operazioni sono estratti di codice da programmi più grandi e devono essere eseguite nel contesto. Mentre le azioni mostrano come richiamare le singole funzioni di servizio, è possibile visualizzare le azioni nel loro contesto nei relativi scenari.
Gli scenari sono esempi di codice che mostrano come eseguire attività specifiche richiamando più funzioni all'interno di un servizio o combinandole con altre Servizi AWS.
Per un elenco completo di guide per AWS SDK sviluppatori ed esempi di codice, consultaUsare DynamoDB con AWS SDK. Questo argomento include anche informazioni su come iniziare e dettagli sulle SDK versioni precedenti.
Nozioni di base
Gli esempi di codice seguenti mostrano come iniziare a utilizzare DynamoDB.
- .NET
-
- AWS SDK for .NET
-
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
namespace DynamoDB_Actions;
public static class HelloDynamoDB
{
static async Task Main(string[] args)
{
var dynamoDbClient = new AmazonDynamoDBClient();
Console.WriteLine($"Hello Amazon Dynamo DB! Following are some of your tables:");
Console.WriteLine();
// You can use await and any of the async methods to get a response.
// Let's get the first five tables.
var response = await dynamoDbClient.ListTablesAsync(
new ListTablesRequest()
{
Limit = 5
});
foreach (var table in response.TableNames)
{
Console.WriteLine($"\tTable: {table}");
Console.WriteLine();
}
}
}
- C++
-
- SDKper C++
-
Codice per il CMakeLists file.txtCMake.
# 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
-
- SDKper 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
-
- SDKper JavaScript (v3)
-
Per maggiori dettagli sull'utilizzo di DynamoDB AWS SDK for JavaScript in, consulta Programmazione di DynamoDB con. 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
-
- SDKper 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
-
- SDKper 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
