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