@Simple understanding and use of conditionalonproperty

@ConditionalOnProperty Annotation controls whether the component is injected spring Annotations

@Configuration
@Slf4j
@EnableScheduling
//@Conditional(CheckEnvironmentCondition.class)
@ConditionalOnProperty(prefix = "demo", name = "conditional", havingValue = "true", matchIfMissing = true)
public class ConditionalConfigTest {

    @Scheduled(cron = "*/5 * * * * ?")
    private void updateJob(){
        System.out.println("ConditionalOnProperty---Test:"+ LocalDateTime.now());
    }
}

Configuration parameters match , Successful injection

  Function of each attribute Source code

@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.TYPE, ElementType.METHOD })
@Documented
@Conditional(OnPropertyCondition.class)
public @interface ConditionalOnProperty {

	/**
	 * Alias for {@link #name()}.
	 * @return the names
	 */
	String[] value() default {};

	/**
	 * A prefix that should be applied to each property. The prefix automatically ends
	 * with a dot if not specified. A valid prefix is defined by one or more words
	 * separated with dots (e.g. {@code "acme.system.feature"}).
	 * @return the prefix
	 */
	String prefix() default "";

	/**
	 * The name of the properties to test. If a prefix has been defined, it is applied to
	 * compute the full key of each property. For instance if the prefix is
	 * {@code app.config} and one value is {@code my-value}, the full key would be
	 * {@code app.config.my-value}
	 * <p>
	 * Use the dashed notation to specify each property, that is all lower case with a "-"
	 * to separate words (e.g. {@code my-long-property}).
	 * @return the names
	 */
	String[] name() default {};

	/**
	 * The string representation of the expected value for the properties. If not
	 * specified, the property must <strong>not</strong> be equal to {@code false}.
	 * @return the expected value
	 */
	String havingValue() default "";

	/**
	 * Specify if the condition should match if the property is not set. Defaults to
	 * {@code false}.
	 * @return if the condition should match if the property is missing
	 */
	boolean matchIfMissing() default false;

}

havingValue： Whether the defined values are equal , Decide whether to inject .

matchIfMissing： If this property is not set , If you need havingValue To match .

  After Baidu , For these two combinations , The explanation is very convoluted , In a nutshell ：

matchIfMissing by true The comparison object is null when , It will inject .

When used together , With havingValue Subject to .