nirmalakumarsahu

Spring Boot with SFTP Integration

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Spring Boot SFTP

Spring Framework Framework

📑 Index

🔑 What is SFTP

SFTP stands for Secure File Transfer Protocol (also known as SSH File Transfer Protocol).

✨ It is a network protocol used to transfer files securely over a protected channel.

🔓 Unlike FTP (File Transfer Protocol), which sends data (including usernames and passwords) in plain text,

🔐 SFTP encrypts both commands and data using SSH (Secure Shell), making it much more secure.

📂➡️🔒 File moves safely from one system to another with full encryption.

🔑 Key Features of SFTP

🔄 SFTP vs FTP vs FTPS

Feature FTP (File Transfer Protocol) FTPS (FTP Secure) SFTP (SSH File Transfer Protocol)
Security No encryption (plain text) SSL/TLS encryption SSH encryption (very secure)
Port 21 (plus random data ports) 21 (plus TLS/SSL) 22 (single port)
Auth Username + Password Username + Password + Certs Username + Password / SSH keys
Protocol FTP only FTP + TLS Built on SSH

🛠️ Example Use Cases

⚙️ How SFTP Works

  1. Connection Initialization

    • The client (you) tries to connect to the SFTP server on port 22 (default for SSH/SFTP).

    • Example:

      sftp user@server.com

  2. Authentication

    • The server authenticates the client using either:

      • Password authentication (username + password), or
      • Public/Private key authentication (using .pem or .ppk files).

    • Keys are more secure because the private key never leaves your machine.

  3. Secure Channel Setup

    • Once authenticated, an SSH encrypted tunnel is established between client and server.
    • This ensures all commands and file data are encrypted.

  4. File Operations

    • Over the secure tunnel, the client can issue commands like:

      • ls → list files
      • cd → change directory
      • get file.txt → download file
      • put report.csv → upload file

    • Unlike FTP, these commands and the file contents are encrypted.

  5. Integrity & Acknowledgement

    • SFTP ensures that files are transferred completely.
    • If a transfer is interrupted, it can resume from where it left off.

  6. Disconnection

    • After the work is done, the client closes the session.

    • Example:

      bye

      🖥️ Example in Action (Linux/Windows Command Line)

# Connect to SFTP server
sftp -i ~/.ssh/id_rsa user@host.com

# Inside SFTP prompt
sftp> ls
sftp> cd /remote/path
sftp> put localfile.txt
sftp> get remotefile.csv
sftp> bye

🔐 In short: SFTP works by combining SSH security + file transfer commands in one protocol, so every action and data packet is encrypted and safe.

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🛠️ Why Use SFTP in Spring Boot?

In enterprise systems, you often need to:

Spring Boot applications integrate with SFTP servers to handle these scenarios.

📦 Library for SFTP in Spring Boot

We use JSch (Java Secure Channel) library:

Maven Central

<dependency>
    <groupId>com.github.mwiede</groupId>
    <artifactId>jsch</artifactId>
    <version>0.2.17</version>
</dependency>

🔑 Key Benefits of Using SFTP in Spring Boot

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🚀 Implementation

🏗️ Technology Stack

🖥️ Backend

📊 API Documentation

🛢️ Database

📂 File Transfer (SFTP)

🛠️ Build & Dependency Management

⚙️ Utilities

📂 Project Structure

spring-boot-sftp-integration
│── 📂 src/
│   └── 📂 main/
│       ├── 📂 java/
│       │   └── 📂 com/sahu/springboot/basics/
│       │       ├── 📂 config/
│       │       │   ├── 📄 OpenApiConfig.java
│       │       │   └── 📄 OpenApiProperties.java
│       │       │
│       │       ├── 📂 constant/
│       │       │   ├── 📄 ApiStatus.java
│       │       │   ├── 📄 AppConstants.java
│       │       │   ├── 📄 AuthenticationType.java
│       │       │   └── 📄 KeyFormat.java
│       │       │
│       │       ├── 📂 controller/rest/
│       │       │   ├── 📄 SftpConfigRestController.java
│       │       │   ├── 📄 SftpFileRestController.java
│       │       │   └── 📄 SftpKeyUtilRestController.java
│       │       │
│       │       ├── 📂 dto/
│       │       │   ├── 📄 ApiResponse.java
│       │       │   ├── 📄 SftpConfigRequest.java
│       │       │   ├── 📄 SftpConfigResponse.java
│       │       │   └── 📄 SftpDirectoryResponse.java
│       │       │
│       │       ├── 📂 exception/
│       │       │   ├── 📄 GlobalExceptionHandler.java
│       │       │   ├── 📄 InvalidSftpKeyFileException.java
│       │       │   ├── 📄 SftpConfigAlreadyExistException.java
│       │       │   ├── 📄 SftpConfigNotFoundException.java
│       │       │   └── 📄 SftpException.java
│       │       │
│       │       ├── 📂 model/
│       │       │   └── 📄 SftpConfig.java
│       │       │
│       │       ├── 📂 operation/
│       │       │   └── 📄 SftpConnectionHandler.java
│       │       │
│       │       ├── 📂 repository/
│       │       │   └── 📄 SftpConfigRepository.java
│       │       │
│       │       ├── 📂 service/
│       │       │   ├── 📂 impl/
│       │       │   │   ├── 📄 FileReaderServiceImpl.java
│       │       │   │   └── 📄 SftpConfigServiceImpl.java
│       │       │   │
│       │       │   ├── 📂 util/
│       │       │   │   └── 📄 SftpConfigUtil.java
│       │       │   │
│       │       │   ├── 📄 FileReaderService.java
│       │       │   └── 📄 SftpConfigService.java
│       │       │
│       │       ├── 📂 util/
│       │       │   ├── 📄 AseCryptUtil.java
│       │       │   └── 📄 SftpKeyConvertorUtil.java
│       │       │
│       │       ├── 📂 validation/
│       │       │   ├── 📄 PortValidator.java
│       │       │   ├── 📄 RemoteDirectoryValidator.java
│       │       │   ├── 📄 SftpConfigAuthValidator.java
│       │       │   ├── 📄 ValidPort.java
│       │       │   ├── 📄 ValidRemoteDirectory.java
│       │       │   └── 📄 ValidSftpConfigAuth.java
│       │       │
│       │       └── 📄 SpringBootSftpIntegrationApplication.java
│       │
│       └── 📂 resources/
│           └── 📄 application.yml
│
│── 📄 docker-compose.yml
└── 📄 pom.xml

🔗 Code Repository

You can find the complete code repository for this project on GitHub:

GitHub - spring-boot-sftp-integration

🚀 To Run the Spring Boot Application

1️⃣ 🐳 Using Docker Compose (for MySQL container)

docker-compose up -d

✅ This starts MySQL in a container (-d = detached mode). 🔍 Verify with:

docker ps

📌 DB is now available at localhost:3307. 🔑 Credentials (username, password, DB name) are in docker-compose.yml.

2️⃣ 💻 Run Directly in IntelliJ IDEA

  1. 📂 Open the Spring Boot project in IntelliJ.
  2. ▶️ In Project Explorer, right-click the main class: SpringBootSftpIntegrationApplication.java
  3. Select Run ‘SpringBootSftpIntegrationApplication’.
  4. 🐞 For debugging, click the Debug button instead of Run.
  5. 🌐 App will start on http://localhost:9897.

3️⃣ ⚡ Run with Maven Command (CLI)

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🎥 Video Reference

For a detailed running and demonstration of the application walkthrough,
watch the following YouTube video:

Watch the video

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📖 Read More ➡️