spring-batch-rs 0.3.4

---
title: Overview
description: Comprehensive guide to all available readers and writers in Spring Batch RS
sidebar:
  order: 1
---

import { Card, CardGrid, Tabs, TabItem } from '@astrojs/starlight/components';

Spring Batch RS provides a rich set of item readers and writers for various data sources and formats. All readers and writers use the builder pattern for easy, type-safe configuration.

## Available Features

Enable only the features you need to keep your dependencies minimal:

| Feature | Description | Status |
|---------|-------------|--------|
| `csv` | CSV file reading and writing | ✅ Stable |
| `json` | JSON file reading and writing | ✅ Stable |
| `xml` | XML file reading and writing | ✅ Stable |
| `mongodb` | MongoDB database integration | ✅ Stable |
| `rdbc-postgres` | PostgreSQL via RDBC | ✅ Stable |
| `rdbc-mysql` | MySQL/MariaDB via RDBC | ✅ Stable |
| `rdbc-sqlite` | SQLite via RDBC | ✅ Stable |
| `orm` | SeaORM integration | ✅ Stable |
| `fake` | Mock data generation | ✅ Stable |
| `logger` | Debug logging writer | ✅ Stable |

## File-Based Readers & Writers

<CardGrid>
  <Card title="CSV" icon="document">
    Read and write CSV files with configurable delimiters, headers, and quoting

    [Learn More →](/item-readers-writers/csv/)
  </Card>
  <Card title="JSON" icon="seti:json">
    Handle JSON arrays and objects with pretty printing support

    [Learn More →](/item-readers-writers/json/)
  </Card>
  <Card title="XML" icon="seti:xml">
    Process XML documents with custom root and item elements

    [Learn More →](/item-readers-writers/xml/)
  </Card>
</CardGrid>

## Database Readers & Writers

<CardGrid>
  <Card title="RDBC (Generic SQL)" icon="seti:db">
    Direct database access for PostgreSQL, MySQL, and SQLite using SQLx

    [Learn More →](/item-readers-writers/rdbc/)
  </Card>
  <Card title="SeaORM" icon="seti:db">
    Type-safe ORM with pagination and filtering

    [Learn More →](/item-readers-writers/orm/)
  </Card>
  <Card title="MongoDB" icon="seti:db">
    Native MongoDB document operations

    [Learn More →](/item-readers-writers/mongodb/)
  </Card>
</CardGrid>

## Utility Readers & Writers

<CardGrid>
  <Card title="Fake Data Generator" icon="star">
    Generate realistic mock data for testing

    [Learn More →](/item-readers-writers/fake/)
  </Card>
  <Card title="Logger Writer" icon="information">
    Debug output for development

    [Learn More →](/item-readers-writers/logger/)
  </Card>
</CardGrid>

## Quick Examples

### CSV Reader

```rust
use spring_batch_rs::item::csv::CsvItemReaderBuilder;
use serde::Deserialize;

#[derive(Deserialize)]
struct Product {
    id: u32,
    name: String,
    price: f64,
}

let reader = CsvItemReaderBuilder::<Product>::new()
    .has_headers(true)
    .delimiter(b',')
    .from_path("products.csv")?;
```

### JSON Writer

```rust
use spring_batch_rs::item::json::JsonItemWriterBuilder;

let writer = JsonItemWriterBuilder::<MyType>::new()
    .pretty_formatter(true)
    .from_path("output.json")?;
```

### Database Reader (RDBC)

```rust
use spring_batch_rs::item::rdbc::rdbc_reader::{RdbcItemReaderBuilder, RdbcRowMapper};
use sqlx::{AnyPool, Row};

struct ProductRowMapper;

impl RdbcRowMapper<Product> for ProductRowMapper {
    fn map_row(&self, row: &sqlx::any::AnyRow) -> Product {
        Product {
            id: row.get("id"),
            name: row.get("name"),
            price: row.get("price"),
        }
    }
}

let pool = AnyPool::connect("postgresql://user:pass@localhost/db").await?;

let reader = RdbcItemReaderBuilder::new()
    .pool(&pool)
    .query("SELECT id, name, price FROM products")
    .page_size(1000)
    .row_mapper(&ProductRowMapper)
    .build();
```

## Custom Readers & Writers

You can create custom implementations by implementing the respective traits:

<Tabs>
  <TabItem label="Custom Reader" icon="document">
    ```rust
    use spring_batch_rs::core::item::ItemReader;
    use spring_batch_rs::BatchError;

    struct MyCustomReader {
        data: Vec<String>,
        index: usize,
    }

    impl ItemReader<String> for MyCustomReader {
        fn read(&mut self) -> ItemReaderResult<String> {
            if self.index < self.data.len() {
                let item = self.data[self.index].clone();
                self.index += 1;
                Ok(Some(item))
            } else {
                Ok(None)  // No more items
            }
        }
    }
    ```
  </TabItem>

  <TabItem label="Custom Writer" icon="seti:db">
    ```rust
    use spring_batch_rs::core::item::ItemWriter;
    use spring_batch_rs::BatchError;

    struct MyCustomWriter {
        output: Vec<String>,
    }

    impl ItemWriter<String> for MyCustomWriter {
        fn write(&mut self, items: &[String]) -> ItemWriterResult {
            for item in items {
                self.output.push(item.clone());
                // Custom write logic here
            }
            Ok(())
        }
    }
    ```
  </TabItem>
</Tabs>

## Performance Considerations

### Chunk Size

Choose appropriate chunk sizes based on your data and memory:

```rust
// Small chunks (10-50): Memory-constrained environments
.chunk(25)

// Medium chunks (100-500): Balanced performance
.chunk(250)

// Large chunks (1000+): High-throughput scenarios
.chunk(1000)
```

### Database Pagination

For database readers, configure page sizes to optimize memory:

```rust
let reader = RdbcItemReaderBuilder::new()
    .page_size(500)  // Fetch 500 records at a time
    .build();
```

### Buffered I/O

File-based readers and writers use buffered I/O by default for optimal performance.

## Next Steps

Explore detailed documentation for each reader and writer type:

- [CSV →](/item-readers-writers/csv/)
- [JSON →](/item-readers-writers/json/)
- [XML →](/item-readers-writers/xml/)
- [RDBC (SQL Databases) →](/item-readers-writers/rdbc/)
- [SeaORM →](/item-readers-writers/orm/)
- [MongoDB →](/item-readers-writers/mongodb/)
- [Fake Data →](/item-readers-writers/fake/)
- [Logger →](/item-readers-writers/logger/)