spring

mvc

model数据封装

view视图

controller接收返回

1. 请求方法映射：
   • @GetMapping：用于处理HTTP GET请求。
   • @PostMapping：用于处理HTTP POST请求。
   • @PutMapping：用于处理HTTP PUT请求。
   • @DeleteMapping：用于处理HTTP DELETE请求。
   • 可以根据不同的HTTP请求方法选择不同的注解，使代码更加清晰。
2. 路径变量：
   • 使用@PathVariable注解可以从URL路径中获取变量的值。
   • 例如，可以将路径中的用户ID作为参数传递给方法：@GetMapping("/users/{id}")
3. 请求参数：
   • 使用@RequestParam注解可以将请求参数的值绑定到方法的参数上。
   • 例如，可以通过以下方式获取名为name的请求参数：public String hello(@RequestParam("name") String name)
4. 请求体：
   • 使用@RequestBody注解可以将请求体的内容绑定到方法的参数上。
   • 例如，可以通过以下方式获取请求体的JSON数据：public String createUser(@RequestBody User user)
5. 响应状态码：
   • 可以使用@ResponseStatus注解指定方法的响应状态码。
   • 例如，可以通过以下方式设置方法的返回状态码为201 CREATED：@ResponseStatus(HttpStatus.CREATED)
6. 异常处理：
   • 可以使用@ControllerAdvice和@ExceptionHandler注解来处理全局异常。
   • 例如，可以创建一个全局异常处理器类，通过@ExceptionHandler注解来处理特定类型的异常。

the annotation

Spring Boot provides a wide range of annotations that facilitate the development of Spring-based applications. Here are some commonly used annotations in Spring Boot:

1. @SpringBootApplication: This annotation is used to mark the main class of a Spring Boot application. It combines @Configuration, @EnableAutoConfiguration, and @ComponentScan annotations, providing a convenient way to bootstrap a Spring application.

2. @Controller: This annotation is used to mark a class as a controller in the MVC pattern. It is typically used in combination with @RequestMapping to handle HTTP requests and produce HTTP responses.

3. @RestController: This annotation is a specialized version of @Controller that combines @Controller and @ResponseBody. It is commonly used for building RESTful APIs, where the return values from the methods are automatically serialized into the HTTP response body.

4. @RequestMapping: This annotation is used to map HTTP requests to specific methods or classes in a controller. It allows you to define the URL path, HTTP methods, request parameters, headers, and more to map the requests to the corresponding controller methods.

5. @PathVariable: This annotation is used to bind a method parameter to a path variable in the URL. It extracts the value from the URL and assigns it to the annotated parameter.

6. @RequestParam: This annotation is used to bind a method parameter to a request parameter in the URL. It extracts the value from the request’s query parameters and assigns it to the annotated parameter.

7. @Autowired: This annotation is used for automatic dependency injection. It allows Spring to automatically resolve and inject dependencies into a bean.

8. @Service: This annotation is used to mark a class as a service component. It is typically used to encapsulate business logic and is often used in combination with @Autowired for dependency injection.

9. @Repository: This annotation is used to mark a class as a repository component. It is typically used to interact with a database or other data sources. Spring Boot provides support for various data access technologies, such as JPA, JDBC, and NoSQL databases.

10. @Configuration: This annotation is used to mark a class as a configuration class. It is often used in conjunction with other annotations like @Bean to define beans and configure the application.

11. @Component: This annotation is a generic stereotype annotation used to mark a class as a Spring component. It is the base annotation for other specialized annotations like @Controller, @Service, and @Repository.

12. @Value: This annotation is used to inject values from external configuration sources, such as properties files or environment variables, into Spring beans.

13. @ConfigurationProperties annotation is a powerful annotation provided by Spring Boot that is used to bind external configuration properties to a Java class. It allows you to map properties from various sources, such as properties files, environment variables, command-line arguments, or YAML files, directly to fields or methods in a Java class.

14. @Nullable the @Nullable annotation is used to indicate that a parameter, field, or method return value can be null. It is primarily used as a form of documentation to convey the nullability behavior of the annotated element.

15. @RestController , it indicates that the class is responsible for handling HTTP requests and producing RESTful responses. The class typically contains methods annotated with @RequestMapping or other request-specific annotations, which are used to map incoming HTTP requests to specific methods in the class.

16. @PreAuthorize, you can define an expression that specifies the conditions under which the method can be executed. This expression typically evaluates the permissions or roles required for accessing the method.

17. @InitBinder@InitBinder is a feature provided by the Spring MVC framework in Java. It is used to customize the data binding process for request parameters in Spring web applications.it is invoked by the framework to initialize a WebDataBinder instance, which is responsible for binding request parameters to method parameters or form backing objects.

These are just a few of the many annotations available in the Spring Boot ecosystem. Spring Boot provides a rich set of annotations that enable developers to simplify and streamline the development of Spring applications.

file name meanings

Certainly! Here are more detailed explanations focusing on the naming conventions and contents of specific file types commonly found in a Spring Boot application:

1. Configuration Classes (e.g., Config.java):

   • Configuration classes are typically named with a suffix of “Config” or “Configuration” (e.g., AppConfig.java, DatabaseConfiguration.java). These classes use annotations like @Configuration, @Bean, or @ComponentScan to define and configure beans, dependencies, and other application settings. They play a crucial role in the Spring framework’s dependency injection mechanism.

2. Controller Classes (e.g., UserController.java):

   • Controller classes handle incoming HTTP requests and define the application’s RESTful endpoints. They are often named with a suffix of “Controller” (e.g., UserController.java, ProductController.java). These classes use annotations like @RestController and @RequestMapping to map requests to specific methods and return appropriate responses.

3. Service Classes (e.g., UserService.java):

   • Service classes encapsulate the business logic of an application and are responsible for processing data and performing operations. They are named with a suffix of “Service” (e.g., UserService.java, OrderService.java). Service classes often use annotations like @Service and may collaborate with repositories, other services, or external APIs to fulfill their responsibilities.

4. Repository/DAO Classes (e.g., UserRepository.java):

   • Repository or DAO (Data Access Object) classes provide an abstraction layer for interacting with databases or other persistent storage systems. They are responsible for querying, saving, and retrieving data. These classes are typically named with a suffix of “Repository” or “DAO” (e.g., UserRepository.java, ProductDAO.java). Spring provides various annotations like @Repository and interfaces like CrudRepository to simplify the implementation of these classes.

5. Entity/Model Classes (e.g., User.java):

   • Entity or model classes represent the domain objects or data structures used in the application. They typically mirror the structure of the underlying database tables or external data sources. Entity classes are commonly named with a singular noun (e.g., User.java, Product.java) and may use annotations like @Entity, @Table, or @Column to define their mapping to the database schema.

6. Exception Classes (e.g., CustomException.java):

   • Exception classes are used to handle and propagate specific errors or exceptional situations within the application. They provide detailed information about the error and may contain custom logic for handling such scenarios. Exception classes are often named with a descriptive name that reflects the specific type of exception or error being handled (e.g., CustomException.java, NotFoundException.java).

7. Utility/Helper Classes (e.g., DateUtils.java):

   • Utility or helper classes provide reusable methods or functions that assist in common tasks or provide additional functionality. They are typically named with a descriptive name that reflects the purpose or functionality they provide (e.g., DateUtils.java, StringUtils.java). Utility classes are often composed of static methods or constants and are used across different parts of the application.

These naming conventions help to provide clarity and maintain consistency within a Spring Boot application. By following these conventions, developers can easily identify the purpose and functionality of different files, making the codebase more organized and understandable.

常用的 Spring Boot 注解及其作用：

1. 依赖注入和组件管理：
   @SpringBootApplication：

主要用于启动类，标识一个 Spring Boot 应用的入口。
包含了 @Configuration、@EnableAutoConfiguration 和 @ComponentScan。
@Controller、@RestController：

用于定义控制器类，处理 HTTP 请求。
@RestController 相当于 @Controller + @ResponseBody。
@Service、@Component：

用于定义服务层组件。
@Service 是 @Component 的特化，表示服务层组件。
@Repository：

用于定义数据访问层组件（如 DAO）。
@Autowired：

自动注入 Bean，用于在属性、构造方法或方法参数上标注，实现依赖注入。
2. Web 开发相关：
@RequestMapping、@GetMapping、@PostMapping：

用于定义请求映射，处理不同 HTTP 方法的请求。
@GetMapping、@PostMapping 等是 @RequestMapping 的简化版本。
@RequestParam、@PathVariable、@RequestBody：

用于获取请求参数、路径变量或请求体中的数据。
@ResponseBody、@ResponseStatus：

@ResponseBody 表示方法返回值直接作为响应体。
@ResponseStatus 定义方法返回的 HTTP 状态码。
@RestControllerAdvice、@ExceptionHandler：

用于全局异常处理，捕获 Controller 层抛出的异常并进行统一处理。
3. 数据访问和事务管理：
@Repository、@Transactional：

@Repository 用于标识数据访问组件。
@Transactional 用于声明事务性方法。
@Entity、@Table、@Column：

用于定义 JPA 实体和表的映射关系。
4. 定时任务和异步处理：
@Scheduled：

用于定义定时任务。
@Async：

用于标记异步方法，使方法调用变为异步执行。
5. 配置和属性相关：
@Configuration、@Bean：

用于定义配置类和 Bean。
@Configuration 标识配置类，@Bean 用于声明 Bean。
@Value、@ConfigurationProperties：

用于注入配置属性。
6. Spring Security 相关：
@EnableWebSecurity、@Secured、@PreAuthorize：
用于配置和管理 Spring Security。
7. 其他常用注解：
@EnableScheduling：

开启 Spring 的定时任务支持。
@EnableAsync： @EnableAsync ：

开启 Spring 的异步方法支持。
@EnableCaching：

开启 Spring 的缓存支持。
@Conditional、@Profile：

用于条件化地配置 Bean 或组件。

org.springframework 提供的一些主要模块和组件：

Spring Core 模块：

提供了 Spring Framework 的核心功能，包括 IoC（Inversion of Control，控制反转）和 DI（Dependency Injection，依赖注入）容器。
核心功能包括 ApplicationContext、BeanFactory、BeanDefinition 等，用于管理和组织应用程序中的对象（Bean）。
Spring AOP 模块：

提供了面向切面编程（AOP）的支持，允许通过切面将横切关注点（如日志、事务管理等）与核心业务逻辑分离。
包括切面、切点、通知、代理等相关组件。
Spring Data 模块：

提供了简化数据库访问的方式，支持集成多种持久化技术（如 JPA、Hibernate、JDBC 等）。
包括 Spring Data JPA、Spring Data JDBC、Spring Data Redis 等子模块。
Spring Web 模块：

提供了构建 Web 应用程序的功能和组件，支持开发 RESTful 服务和传统的 Web 应用。
包括 Spring MVC、Spring WebFlux、WebSocket 支持等。
Spring Security 模块：

提供了身份认证和授权的功能，用于保护应用程序的安全性。
支持基于角色或权限的访问控制、表单登录、OAuth2 认证等。
Spring Boot 模块：

提供了简化 Spring 应用程序开发的工具和约定，包括自动配置、快速启动、外部化配置等。
让开发人员可以快速搭建和部署独立的、生产级别的 Spring 应用程序。
Spring Batch 模块：

提供了大数据量批处理作业的支持，用于处理大规模数据的定时、批量任务。
Spring Integration 模块：

提供了消息驱动的、事件驱动的编程模型，支持构建企业集成应用。
Spring Messaging 模块：

提供了对消息传递和消息处理的支持，包括 JMS、WebSocket 等协议的集成。
Spring Test 模块：

提供了测试 Spring 应用程序的支持，包括单元测试、集成测试和端到端测试。

Swagger

一个开源框架，可让您为 RESTful API 描述、记录和生成客户端 SDK。
它提供了一种使用 JSON 或 YAML 文件（称为 Swagger 规范）来定义 API 的结构和行为的方法。
使用Swagger，您可以轻松生成交互式API文档，自动生成多种编程语言的客户端SDK，并进行API测试和验证。
通过使用 Swagger，您可以为 API 使用者提供清晰且全面的文档，从而改善开发人员体验。
{In the context of Spring Boot, Docket is a class provided by the Springfox library, which is used for configuring and customizing the documentation of your RESTful APIs using the Swagger framework. Swagger is a popular tool for designing, building, and documenting APIs.}

DB

Druid 是阿里巴巴开源的一个数据库连接池和监控组件，它提供了高性能、可扩展、可监控的数据库连接池，支持 JDBC 和非 JDBC 数据源，同时还集成了强大的数据库连接池监控功能。