Rust与Java DynamoDB、MySQL CRM、tokio-pg、SVM、Custors实战指南
基于Rust、Java和DynamoDB的实用示例
以下是一些基于Rust和DynamoDB的实用示例，涵盖从基础操作到高级功能的实现方式。示例使用官方AWS SDK aws-sdk-dynamodb 或社区库如 rusoto_dynamodb。
基础操作：表管理
创建表
use aws_sdk_dynamodb::{Client, Error};
async fn create_table(client: &Client, table_name: &str) -> Result<(), Error> {let response = client.create_table().table_name(table_name).key_schema(aws_sdk_dynamodb::types::KeySchemaElement::builder().attribute_name("id").key_type(aws_sdk_dynamodb::types::KeyType::Hash).build(),).attribute_definitions(aws_sdk_dynamodb::types::AttributeDefinition::builder().attribute_name("id").attribute_type(aws_sdk_dynamodb::types::ScalarAttributeType::S).build(),).billing_mode(aws_sdk_dynamodb::types::BillingMode::PayPerRequest).send().await?;println!("Table created: {:?}", response.table_description);Ok(())
}
删除表
async fn delete_table(client: &Client, table_name: &str) -> Result<(), Error> {client.delete_table().table_name(table_name).send().await?;println!("Table deleted");Ok(())
}
数据操作：增删改查
插入数据
async fn put_item(client: &Client, table_name: &str, id: &str, value: &str) -> Result<(), Error> {let item = serde_dynamo::to_item(serde_json::json!({"id": id,"value": value}))?;client.put_item().table_name(table_name).set_item(Some(item)).send().await?;Ok(())
}
批量写入
async fn batch_write(client: &Client, table_name: &str, items: Vec<serde_json::Value>) -> Result<(), Error> {let writes = items.into_iter().map(|item| {aws_sdk_dynamodb::types::WriteRequest::builder().put_request(aws_sdk_dynamodb::types::PutRequest::builder().set_item(Some(serde_dynamo::to_item(item).unwrap())).build(),).build()}).collect::<Vec<_>>();client.batch_write_item().request_items(table_name, writes).send().await?;Ok(())
}
查询数据
async fn get_item(client: &Client, table_name: &str, id: &str) -> Result<(), Error> {let response = client.get_item().table_name(table_name).key("id", aws_sdk_dynamodb::types::AttributeValue::S(id.to_string())).send().await?;println!("Item: {:?}", response.item);Ok(())
}
高级功能
条件更新
async fn conditional_update(client: &Client, table_name: &str, id: &str, new_value: &str) -> Result<(), Error> {client.update_item().table_name(table_name).key("id", aws_sdk_dynamodb::types::AttributeValue::S(id.to_string())).update_expression("SET #v = :newval").condition_expression("#v = :oldval").expression_attribute_names("#v", "value").expression_attribute_values(":newval", aws_sdk_dynamodb::types::AttributeValue::S(new_value.to_string())).expression_attribute_values(":oldval", aws_sdk_dynamodb::types::AttributeValue::S("old_value".to_string())).send().await?;Ok(())
}
事务操作
async fn transact_write(client: &Client, table_name: &str, id1: &str, id2: &str) -> Result<(), Error> {client.transact_write_items().transact_items(aws_sdk_dynamodb::types::TransactWriteItem::builder().put(aws_sdk_dynamodb::types::Put::builder().table_name(table_name).item("id", aws_sdk_dynamodb::types::AttributeValue::S(id1.to_string())).item("value", aws_sdk_dynamodb::types::AttributeValue::S("data1".to_string())).build(),).build(),).transact_items(aws_sdk_dynamodb::types::TransactWriteItem::builder().delete(aws_sdk_dynamodb::types::Delete::builder().table_name(table_name).key("id", aws_sdk_dynamodb::types::AttributeValue::S(id2.to_string())).build(),).build(),).send().await?;Ok(())
}
索引与查询优化
全局二级索引查询
async fn query_gsi(client: &Client, table_name: &str, index_name: &str, value: &str) -> Result<(), Error> {let response = client.query().table_name(table_name).index_name(index_name).key_condition_expression("#v = :val").expression_attribute_names("#v", "value").expression_attribute_values(":val", aws_sdk_dynamodb::types::AttributeValue::S(value.to_string())).send().await?;println!("Query results: {:?}", response.items);Ok(())
}
分页处理
async fn paginated_scan(client: &Client, table_name: &str) -> Result<(), Error> {let mut last_evaluated_key = None;loop {let response = client.scan().table_name(table_name).set_exclusive_start_key(last_evaluated_key).limit(10).send().await?;println!("Page items: {:?}", response.items);last_evaluated_key = response.last_evaluated_key;if last_evaluated_key.is_none() {break;}}Ok(())
}
实用工具
数据序列化工具
use serde::{Serialize, Deserialize};
#[derive(Serialize, Deserialize)]
struct Item {id: String,value: String,
}
async fn serialize_item(client: &Client, table_name: &str, item: Item) -> Result<(), Error> {let item_av = serde_dynamo::to_item(item)?;client.put_item().table_name(table_name).set_item(Some(item_av)).send().await?;Ok(())
}
错误处理
async fn handle_errors(client: &Client, table_name: &str) {match get_item(client, table_name, "nonexistent_id").await {Ok(_) => println!("Item found"),Err(aws_sdk_dynamodb::types::SdkError::ServiceError { err, .. }) => {println!("DynamoDB error: {:?}", err);}Err(e) => println!("Unexpected error: {:?}", e),}
}
以上示例覆盖了DynamoDB的核心功能，可根据实际需求调整参数或组合使用。完整项目建议参考AWS SDK官方文档和serde_dynamo库的序列化能力。
Java与Amazon DynamoDB交互
以下是Java与Amazon DynamoDB交互的实用示例，涵盖基础操作到高级功能，均使用AWS SDK for Java 2.x版本实现。
基础操作示例
创建DynamoDB客户端
DynamoDbClient client = DynamoDbClient.builder().region(Region.US_EAST_1).credentialsProvider(ProfileCredentialsProvider.create("default")).build();
创建表
CreateTableRequest request = CreateTableRequest.builder().attributeDefinitions(AttributeDefinition.builder().attributeName("id").attributeType(ScalarAttributeType.S).build()).keySchema(KeySchemaElement.builder().attributeName("id").keyType(KeyType.HASH).build()).provisionedThroughput(ProvisionedThroughput.builder().readCapacityUnits(10L).writeCapacityUnits(10L).build()).tableName("Users").build();client.createTable(request);
插入数据
PutItemRequest request = PutItemRequest.builder().tableName("Users").item(Map.of("id", AttributeValue.builder().s("user123").build(),"name", AttributeValue.builder().s("John Doe").build(),"age", AttributeValue.builder().n("30").build())).build();client.putItem(request);
获取单条数据
GetItemRequest request = GetItemRequest.builder().tableName("Users").key(Map.of("id", AttributeValue.builder().s("user123").build())).build();GetItemResponse response = client.getItem(request);
批量写入
List<WriteRequest> writeRequests = new ArrayList<>();
writeRequests.add(WriteRequest.builder().putRequest(PutRequest.builder().item(Map.of("id", AttributeValue.builder().s("user456").build(),"name", AttributeValue.builder().s("Jane Smith").build())).build()).build());BatchWriteItemRequest request = BatchWriteItemRequest.builder().requestItems(Map.of("Users", writeRequests)).build();client.batchWriteItem(request);
查询与扫描示例
简单查询
QueryRequest request = QueryRequest.builder().tableName("Orders").keyConditionExpression("customerId = :cid").expressionAttributeValues(Map.of(":cid", AttributeValue.builder().s("cust100").build())).build();QueryResponse response = client.query(request);
带过滤的扫描
ScanRequest request = ScanRequest.builder().tableName("Products").filterExpression("price > :minPrice").expressionAttributeValues(Map.of(":minPrice", AttributeValue.builder().n("50").build())).build();ScanResponse response = client.scan(request);
分页查询
QueryRequest request = QueryRequest.builder().tableName("Messages").limit(10).exclusiveStartKey(lastEvaluatedKey).build();QueryResponse response = client.query(request);
Map<String, AttributeValue> lastKey = response.lastEvaluatedKey();
高级功能示例
事务操作
TransactWriteItemsRequest request = TransactWriteItemsRequest.builder().transactItems(TransactWriteItem.builder().put(Put.builder().tableName("Inventory").item(/* item data */).build()).build(),TransactWriteItem.builder().update(Update.builder().tableName("Orders").key(/* key */).updateExpression("SET status = :s").expressionAttributeValues(/* values */).build()).build()).build();client.transactWriteItems(request);
条件更新
UpdateItemRequest request = UpdateItemRequest.builder().tableName("Accounts").key(Map.of("accountId", AttributeValue.builder().s("acc123").build())).updateExpression("SET balance = balance + :deposit").conditionExpression("attribute_exists(accountId)").expressionAttributeValues(Map.of(":deposit", AttributeValue.builder().n("100.00").build())).build();client.updateItem(request);
二级索引示例
全局二级索引查询
QueryRequest request = QueryRequest.builder().tableName("Products").indexName("CategoryIndex").keyConditionExpression("category = :cat").expressionAttributeValues(Map.of(":cat", AttributeValue.builder().s("Electronics").build())).build();client.query(request);
错误处理示例
处理ConditionalCheckFailedException
try {UpdateItemRequest request = /* request with condition */;client.updateItem(request);
} catch (ConditionalCheckFailedException e) {System.err.println("Item did not meet the expected conditions");
}
性能优化示例
启用分页自动迭代
QueryIterable queryIterable = client.queryPaginator(QueryRequest.builder().tableName("LargeTable").build());queryIterable.items().forEach(item -> {// 处理每个item
});
其他实用示例
获取表描述信息
DescribeTableRequest request = DescribeTableRequest.builder().tableName("Users").build();DescribeTableResponse response = client.describeTable(request);
TableDescription table = response.table();
删除表
DeleteTableRequest request = DeleteTableRequest.builder().tableName("TempTable").build();client.deleteTable(request);
更新表吞吐量
UpdateTableRequest request = UpdateTableRequest.builder().tableName("HighTrafficTable").provisionedThroughput(ProvisionedThroughput.builder().readCapacityUnits(50L).writeCapacityUnits(50L).build()).build();client.updateTable(request);
以上示例覆盖DynamoDB核心操作场景，实际使用时需根据具体业务需求调整参数和异常处理逻辑。建议结合AWS官方文档进行更深入的功能探索。
基于Rust和MySQL的CRM系统实例
以下是一个基于Rust和MySQL的CRM系统实例，包含功能的代码示例。这些示例涵盖了从数据库连接到复杂查询的典型CRM操作。
数据库连接与初始化
use mysql::*;
use mysql::prelude::*;let url = "mysql://username:password@localhost:3306/crm_db";
let pool = Pool::new(url)?;
let mut conn = pool.get_conn()?;
客户表创建
conn.query_drop(r"CREATE TABLE IF NOT EXISTS customers (id INT AUTO_INCREMENT PRIMARY KEY,name VARCHAR(255) NOT NULL,email VARCHAR(255) UNIQUE,phone VARCHAR(50),created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP)"
)?;
插入新客户
let new_customer = ("John Doe", "john@example.com", "+123456789");
conn.exec_drop("INSERT INTO customers (name, email, phone) VALUES (?, ?, ?)",new_customer
)?;
批量插入客户
let customers = vec![("Alice Smith", "alice@example.com", "+987654321"),("Bob Johnson", "bob@example.com", "+1122334455")
];conn.exec_batch("INSERT INTO customers (name, email, phone) VALUES (?, ?, ?)",customers.iter().map(|c| (c.0, c.1, c.2))
)?;
查询所有客户
let customers: Vec<(i32, String, String, String)> = conn.query_map("SELECT id, name, email, phone FROM customers",|(id, name, email, phone)| (id, name, email, phone)
)?;
按ID查询客户
let customer_id = 1;
let customer: Option<(String, String)> = conn.query_first("SELECT name, email FROM customers WHERE id = ?",(customer_id,)
)?;
更新客户信息
conn.exec_drop("UPDATE customers SET phone = ? WHERE id = ?",("+15555555555", 1)
)?;
删除客户
conn.exec_drop("DELETE FROM customers WHERE id = ?",(2,)
)?;
交易记录表
conn.query_drop(r"CREATE TABLE IF NOT EXISTS transactions (id INT AUTO_INCREMENT PRIMARY KEY,customer_id INT NOT NULL,amount DECIMAL(10,2) NOT NULL,date DATE NOT NULL,FOREIGN KEY (customer_id) REFERENCES customers(id))"
)?;
添加交易记录
let transaction = (1, 199.99, "2023-05-15");
conn.exec_drop("INSERT INTO transactions (customer_id, amount, date) VALUES (?, ?, ?)",transaction
)?;
客户交易统计
let stats: Vec<(String, f64)> = conn.query_map(r"SELECT c.name, SUM(t.amount) as total FROM customers c JOIN transactions t ON c.id = t.customer_id GROUP BY c.id",|(name, total)| (name, total)
)?;
分页查询客户
let page = 1;
let per_page = 10;
let offset = (page - 1) * per_page;let customers: Vec<(String, String)> = conn.query_map("SELECT name, email FROM customers LIMIT ? OFFSET ?",(per_page, offset),|(name, email)| (name, email)
)?;
搜索客户
let search_term = "%john%";
let results: Vec<(String, String)> = conn.query_map("SELECT name, email FROM customers WHERE name LIKE ? OR email LIKE ?",(search_term, search_term),|(name, email)| (name, email)
)?;
客户活动记录表
conn.query_drop(r"CREATE TABLE IF NOT EXISTS activities (id INT AUTO_INCREMENT PRIMARY KEY,customer_id