英文:
Call method after bean initialization but before @Bean called
问题
@Configuration
public class MyAppConfiguration extends MyBaseAppConfiguration {
@Bean
public MyDAOBean getMyDAOBean() {
boolean isEmpty = myString.isEmpty();
return new MyDAOBean();
}
}
@Component
@ConfigurationProperties(prefix="hey")
@Getter
@Setter
public class MyBean {
private String myString;
}
public class MyBaseAppConfiguration {
@Autowired
private MyBean myBean;
protected String myString;//I need some annotation to call this (@PostConstruct maybe?)public void setMyString() {this.myString = myBean.getMyString();}
}
I want to set myString with something that I got from myBean. So I need some annotation to call the method that sets this field after myBean is initialized but before getMyDAOBean is called. @PostConstruct currently works for this situation, but I need to be sure if it always works. Does it do the job, or is there something I don't know, and this is risky?
Please ignore the simplicity of the example. myBean.getMyString() in getMyDAOBean would be easier, but it's more complex in reality. Just focus on the problem.
Edit: How about the setter-injection way? Does it make any difference? Is it safer or something else?
public class MyBaseAppConfiguration {
protected String myString;
@Autowiredpublic void setMyString(MyBean myBean) {this.myString = myBean.getMyString();}
}
英文:
@Configurationpublic class MyAppConfiguration extends MyBaseAppConfiguration {@Beanpublic MyDAOBean getMyDAOBean() {boolean isEmpty = myString.isEmpty();return new MyDAOBean();}}@Component@ConfigurationProperties(prefix="hey")@Getter@Setterpublic class MyBean {private String myString;}public class MyBaseAppConfiguration {@Autowiredprivate MyBean myBean;protected String myString;//I need some annotation to call this (@PostConstruct maybe?)public void setMyString() {this.myString= myBean.getMyString();}}
I want to set myString with something that I got from myBean. So I need some annotation to call method that I set this field after myBean initiliazed but before getMyDAOBean called. @PostConstruct currently working for this situation but I need to be sure if it is always working. Does it do the job or there is something I don't know and this is risky?
Please ignore simplicity of example. myBean.getMyString() in getMyDAOBean would be more easy but It's more complex in real, just focus on the problem.
Edit: How about setter-injection way? Does it make any difference? More safety or else?
public class MyBaseAppConfiguration {protected String myString;@Autowiredpublic void setMyString(MyBean myBean) {this.myString= myBean.getMyString();}}
答案1
得分: 1
你可以将MyBean添加为构造函数注入。
public class MyBaseAppConfiguration {protected String myString;@Autowiredpublic MyBaseAppConfiguration(MyBean myBean){myString = myBean.getMyString();}}
英文:
You can add MyBean as a constructor injection.
public class MyBaseAppConfiguration {protected String myString;@Autowiredpublic MyBaseAppConfiguration(MyBean myBean ){myString = myBean.getMyString();}
}
答案2
得分: 1
The creation of the bean for MyDAOBean seems to have some dependency on a computed value based on the property of MyBean.
@Conditional 注解以及自定义条件可以用来执行所需的操作；在这种情况下是 myString.isEmpty()。
import org.springframework.context.annotation.Condition;import org.springframework.context.annotation.ConditionContext;import org.springframework.core.type.AnnotatedTypeMetadata;import java.util.Objects;public class MyStringIsEmpty implements Condition {@Overridepublic boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {// 获取 MyBean 的 Spring BeanMyBean myBean = Objects.requireNonNull(context.getBeanFactory()).getBean(MyBean.class);// 获取 myString 属性String myString = myBean.getMyString();// 执行所需的评估boolean isEmpty = myString.isEmpty();return isEmpty; // 如果为 true，则创建该 Bean}}
使用自定义条件。
import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Conditional;@Bean@Conditional(MyStringIsEmpty.class)public MyDAOBean getMyDAOBean() {return new MyDAOBean();}
英文:
The creation of the bean for MyDAOBean seems to have some dependency on a computed value based on the property of MyBean.
The @Conditional annotation alongside a custom condition can be used to do the operations required; myString.isEmpty() is this case.
import org.springframework.context.annotation.Condition;import org.springframework.context.annotation.ConditionContext;import org.springframework.core.type.AnnotatedTypeMetadata;import java.util.Objects;public class MyStringIsEmpty implements Condition {@Overridepublic boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {// Get the spring bean for MyBeanMyBean myBean = Objects.requireNonNull(context.getBeanFactory()).getBean(MyBean.class);// Get the property of myStringString myString = myBean.getMyString();// perform your desired evaluationboolean isEmpty = myString.isEmpty();return isEmpty; // if true, the bean will be created}}
Using the custom condition.
import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Conditional;@Bean@Conditional(MyStringIsEmpty.class)public MyDAOBean getMyDAOBean() {return new MyDAOBean();}
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