What are the common annotations for springboot?

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springboot common annotations

1, @SpringBootApplication

Includes @Configuration, @EnableAutoConfiguration, @ComponentScan

is usually used in the main class superior.

2. @Repository

is used to mark data access components, that is, DAO components.

3. @Service

is used to mark business layer components.

4. @RestController

is used to mark control layer components (such as actions in struts), including @Controller and @ResponseBody

5. @ResponseBody

means that the return result of this method is directly written into the HTTP response body

is generally used when obtaining data asynchronously. After using @RequestMapping, The return value is usually parsed as a jump path. After adding @responsebody, the return result will not be parsed

as a jump path, but will be written directly into the HTTP response body. For example, if you obtain json data asynchronously and add @responsebody, the json data will be returned directly.

6. @Component

refers to components in general. When components are difficult to classify, we can use this annotation to annotate them.

7, @ComponentScan

Component scan. Equivalent to 611dfb857b03b245adf9fd6566a6e09a, if classes with @Component @Controller @Service and other annotations are scanned,

these classes will be registered as beans.

8. @Configuration

points out that this class is the information source of Bean configuration, which is equivalent to 3c9fdce8078791299ca92e41bddc2b8fa6748f3712e7c0e1f60ffca24b3db7b0 in XML. It is usually added in On the main category.

9. @Bean

is equivalent to 60e23eb984d18edbb092da6b8f295aba4bb0e59fd50cbfe6f6ce2215b9d94243 in XML. It is placed above the method instead of the class, which means to generate A bean and managed by spring.

10. @EnableAutoConfiguration

Let Spring Boot automatically configure the Spring framework based on the dependencies declared by the application, usually added to the main class.

11, @AutoWired

byType method. Use the configured beans to complete the assembly of properties and methods. It can annotate class member variables, methods and constructors to complete automatic assembly.
When (required=false) is added, no error will be reported even if the bean cannot be found.

12. @Qualifier

When there are multiple beans of the same type, you can use @Qualifier("name") to specify. Used in conjunction with @Autowired

13, @Resource(name="name",type="type")

If there is no content in brackets, byName will be used by default. Do similar things with @Autowired.

14. @RequestMapping

RequestMapping is an annotation used to handle request address mapping and can be used on classes or methods. Used on a class, it means that all methods in the class that respond to requests use this address as the parent path.

This annotation has six attributes:

params: Specify that the request must contain certain parameter values ​​before it can be processed by this method.

headers: The specified request must contain certain specified header values ​​in order for this method to process the request.

value: Specify the actual address of the request, the specified address can be a URI Template mode

method: Specify the method type of the request, GET, POST, PUT, DELETE, etc.

consumes: Specifies the submitted content type (Content-Type) for processing the request, such as application/json, text/html;

produces: Specifies the returned content type, only when the (Accept) type in the request header

#15 is returned only if it contains the specified type. @RequestParam

is used in front of the parameters of the method.

@RequestParam String a =request.getParameter("a")。

16, @PathVariable

Path variable. The parameters must be the same as the names in the curly brackets.

RequestMapping("user/get/mac/{macAddress}")
public String getByMacAddress(@PathVariable String macAddress){
　　//do something;
　　}

17, @Profiles

Spring Profiles provide a way to isolate application configurations and make these configurations only effective in specific environments.

Any @Component or @Configuration can be marked with @Profile, thereby limiting the timing of loading it.

@Configuration
@Profile("prod")
public class ProductionConfiguration {    // ...}

18, @ConfigurationProperties

Spring Boot will try to verify external configuration, using JSR-303 by default (if it is in the classpath).

You can easily add JSR-303 javax.validation constraint annotations to your @ConfigurationProperties class:

@Component
@ConfigurationProperties(prefix="connection")
public class ConnectionSettings {
@NotNullprivate InetAddress remoteAddress;
// ... getters and setters
}

Global exception handling

@ControllerAdvice

Contains @Component. can be scanned.

Uniform handling of exceptions

@ExceptionHandler (Exception.class):

Used above the method to indicate that the following method will be executed when encountering this exception

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