标签：welcome etl nfa override strong spring -- win7 实例化
下面来介绍如何使用@Condition
@Conditional(TestCondition.class)
这句代码可以标注在类上面，表示该类下面的所有@Bean都会启用配置，也可以标注在方法上面，只是对该方法启用配置。
spring框架还提供了很多@Condition给我们用，当然总结用语哪种好理解，看给位读者喽
@ConditionalOnBean（仅仅在当前上下文中存在某个对象时，才会实例化一个Bean）
@ConditionalOnClass（某个class位于类路径上，才会实例化一个Bean）
@ConditionalOnExpression（当表达式为true的时候，才会实例化一个Bean）
@ConditionalOnMissingBean（仅仅在当前上下文中不存在某个对象时，才会实例化一个Bean）
@ConditionalOnMissingClass（某个class类路径上不存在的时候，才会实例化一个Bean）
@ConditionalOnNotWebApplication（不是web应用）
后续会继续补充
另一种总结
public class InitConditional implements Condition{
@Override
public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
//判断是否已经包含了amazonTest Bean
Boolean bol = conditionContext.getBeanFactory().containsBean("amazonTest");
return bol;
}
}
使用自定义的Conditional
@Component
@Conditional(InitConditional.class)
public class AmazonTest {
@Autowired
private AmazonProperties amazonProperties;
public void testGet(){
System.out.println(" testGet Associated");
System.out.println(amazonProperties.getAssociateId());
}
}
WelcomeController 与 AmazonTest关联，使用ConditionOnBean（如果条件的bean存在，当前的bean才会被声明）
@Component
@ConditionalOnBean(AmazonTest.class)
public class WelcomeController {
private static final Logger logger = LoggerFactory.getLogger(WelcomeController.class);
private AppProperties app;
private GlobalProperties global;
@Autowired
public void setApp(AppProperties app) {
this.app = app;
}
@Autowired
public void setGlobal(GlobalProperties global) {
this.global = global;
}
public void testWelcome(){
String appProperties = app.toString();
String globalProperties = global.toString();
System.out.println(appProperties);
System.out.println(globalProperties);
}
}
main测试文件入口
public static void main(String[] args) {
ConfigurableApplicationContext configurableApplicationContext =SpringApplication.run(DemoApplication.class, args);
//bean自动注册，根据bean的名字获取Bean
AmazonProperties amazonProperties = (AmazonProperties) configurableApplicationContext.getBean("amazonProperties");
System.out.println(amazonProperties.getAssociateId());
Boolean aBooleanWelcomeController = configurableApplicationContext.containsBean("welcomeController");
if(!aBooleanWelcomeController){
System.out.println(" welcomeController init fail");
}else{
WelcomeController welcomeController = (WelcomeController) configurableApplicationContext.getBean("welcomeController");
System.out.println(" welcomeController init Success");
}
Boolean aBooleanAmazonTest = configurableApplicationContext.containsBeanDefinition("amazonTest");
if(!aBooleanAmazonTest){
System.out.println(" amazonTest init fail");
}else{
AmazonTest amazonTest = (AmazonTest) configurableApplicationContext.getBean("amazonTest");
System.out.println(" amazonTest init Success");
}
}
springBoot----@ConditionalOnxxx相关注解总结
标签：welcome etl nfa override strong spring -- win7 实例化
原文地址：https://www.cnblogs.com/jiligalaer/p/12070623.html
