Spring4 provides a more general way to create conditions for Bean, and that the use of @Conditional comment.
Example:
IfCreate by modifying values in the configuration file to control the creation of a Bean.
(1) create a class that implements the Condition interface methods to achieve matches, matches the results returned by the method determines whether Bean is created.
package learnspring.learnspring.conditional;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;
/**
* @author 肖政宇
* @date 2019-09-26 14:33
* 说明：判断条件
*/
public class MyCondition implements Condition {
@Override
public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
String ifCreate = conditionContext.getEnvironment() .getProperty ( "ifCreate" ) ;
IF ( "to true" .equals (ifCreate )) {
. the System Out.println ( "profile, ifCreate value to true" ) ;
return to true; } the else { . the System OUT .println ( "profile, ifCreate value to false" ) ; return to false; } } }
（2）Bean
learnspring.learnspring.conditional Package Penalty for ;
/ **
* @author Xiao Zhengyu
* @date 2019-09-26 14:45
* Description:
* /
public class the DemoBean { public the DemoBean () { System. out.println ( "the Hello, already the DemoBean created "! ) ; } }
(3) java class configuration
package learnspring.learnspring.conditional;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
/**
* @author 肖政宇
* @date 2019-09-26 14:46
* 说明：
*/
@Configuration
public class MyConditionalConfiguration {
@Bean
@Conditional(MyCondition.class)
public DemoBean createBeanConditional() {
return new DemoBean();
}
}
(4) configuration file
(5) operating results
