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This article mainly introduces "what is the method of configuration verification when SpringBoot development starts". In daily operation, I believe that many people have doubts about the method of configuration verification when SpringBoot development is started. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "what is the method of configuration verification when SpringBoot development starts?" Next, please follow the editor to study!

Overview

During the development of a project, a function depends on the parameters configured in the configuration file. At this time, the following phenomenon problems may arise:

Sometimes a project starts up, and an exception occurs when using a functional component, indicating that the parameters are not configured or that bean injection fails.

Is there a way to check the parameters at the start of the project instead of throwing prompts when they are actually used?

The answer is to use the Java Validation function provided by Spring, which is simple and practical.

Add startup check

You only need to add Validation-related configuration to the configuration Properties class we created.

@ Validated@Data@ConfigurationProperties (prefix = "app") @ Componentpublic class AppConfigProperties {@ NotEmpty (message = "profile configuration must configure the [app.id] property") private String id;}

The above configuration will verify whether we have configured the app.id parameter in application.yml. If the configuration is not in the configuration file, the project startup fails and a check exception is thrown.

When using configuration file validation, you must use the @ configurationproperties annotation, which is not supported by @ value.

You can inject the configuration class when you need to use app.id:

@ Autowiredprivate AppConfigProperties appConfigProperties

In this way, we can achieve the desired effect, as shown in the following figure:

Effect.

The check type check rule rule states that the @ Null limit can only be null@NotNull limit must not be null@AssertFalse limit must be false@AssertTrue limit must be true@DecimalMax (value) limit must be a number not greater than the specified value @ DecimalMin (value) limit must be a number not less than the specified value @ Digits (integer,fraction) limit must be a decimal, and the number of digits of the integer cannot exceed integer The number of decimal places must not exceed the fraction@Future limit must be a future date @ Max (value) limit must be a number not greater than the specified value @ Min (value) limit must be a number not less than the specified value @ Past validate that the element value (date type) of the annotation is earlier than the current time @ Pattern (value) limit must conform to the specified regular expression @ Size (max) Min) limit character length must be between min and max. @ NotEmpty validates that the element value of the annotation is not null and is not empty (string length is not 0, set size is not 0) @ NotBlank verifies that the element value of the annotation is not empty (not null, length is 0 after removing the first space) Unlike @ NotEmpty,@NotBlank, which applies only to strings and removes string spaces during comparison, @ Email verifies that the element value of the annotation is Email, or you can specify a custom email format through regular expressions and flag

Validation supports the following checks, which can satisfy the basic business logic. Of course, if you still can't satisfy your business logic, you can choose to customize the verification rules.

Custom check logic

Define check logic rules and implement org.springframework.validation.Validator

Public class ConfigPropertiesValidator implements Validator {@ Override public boolean supports (Class aClass) {return AppConfigProperties.class.isAssignableFrom (aClass);} @ Override public void validate (Object o, Errors errors) {AppConfigProperties config = (AppConfigProperties) o; if (StringUtils.isEmpty (config.getId () {errors.rejectValue ("id", "app.id.empty", "[app.id] attribute must be configured in the configuration file") } else if (config.getId (). Length () < 5) {errors.rejectValue ("id", "app.id.short", "[app.id] attribute length must not be less than 5");}

Using custom verification rules eliminates the need to use the native @ NotEmpty, delete it

@ Validated@Data@ConfigurationProperties (prefix = "app") @ Componentpublic class AppConfigProperties {/ / @ NotEmpty (message = "profile configuration must configure the [app.id] property") private String id;}

Inject custom verification rules

@ Beanpublic ConfigPropertiesValidator configurationPropertiesValidator () {return new ConfigPropertiesValidator ();}

Note: the method name of bean here must be configurationPropertiesValidator, otherwise the check will not be performed at startup

Modify the app.id configuration and observe the startup

Test verification results

The error message is the result of our custom check.

At this point, the study on "what is the method of configuration verification when SpringBoot development starts" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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