Introduce the basic concepts and advantages of Docker, as well as its practical application in application development

Docker is an open source containerization platform that allows developers to package applications and the components they depend on (such as libraries and runtime environments) into a portable, self-contained container. This container can run in any environment that supports Docker, including development, testing, production and other environments. The basic concepts of Docker include the following aspects:

1. Image: An image is a read-only template that contains all the information about an application and the components it depends on.

2. Container: A container is a runnable instance created based on an image and contains all the resources needed to run an application.

3. Repository: A repository is a place where images are stored. It can be a public cloud warehouse (such as Docker Hub) or a private warehouse.

Key benefits of Docker include:

1. Lightweight: Docker containers are more lightweight than virtual machines, can be created and started quickly, and occupy less system resources.

2. Portability: Docker containers can run in any environment that supports Docker, ensuring application portability. At the same time, because Docker can be consistent between the local development environment and the production environment, application running problems caused by environmental differences can be avoided.

3. Rapid deployment: Docker containers can be deployed quickly, a container can be started or stopped in a few seconds, and can be managed and expanded through automated tools.

There are many practical applications of Docker in application development. These include:

1. Development environment management: Docker can help developers quickly build a local development environment and reduce the cost and workload of environment configuration.

2. Application deployment: Docker can help package applications into containers for easy deployment and expansion.

3. Automated testing: Docker can help developers quickly create a test environment and ensure consistency between the test environment and the production environment.

4. Microservice architecture: Docker can help developers quickly deploy and manage microservices, improving the flexibility and scalability of the system.