[英]Spring dependency injection with @Autowired annotation without setter
[英]How to use @Required annotation in setter injection in spring?
@必需的注釋用法。 我嘗試使用上面的setter方法,並嘗試從上下文中查找Bean,而不設置此依賴項。 我得到的對象的依賴項設置為null,我期望spring會拋出一些異常。 請指導我我做錯了什么?
@Required to make it mandatory that the dependency has to be injected
讓我們舉個例子:我們需要使用RequiredAnnotationPostProcessor來檢查是否已注入@Required
依賴項。
public class BankService {
private CustomerService customerService;
private BillPaymentService billPaymentService;
@Required
public void setCustomerService(CustomerService customerService) {
this.customerService = customerService;
}
@Required
public void setBillPaymentService(BillPaymentService billPaymentService) {
this.billPaymentService = billPaymentService;
}
}
配置就像
<bean id="custService" class="xml.CustomerServiceImpl" />
<bean id="billingService" class="xml.BillPaymentServiceImpl" />
<bean id="bankService" class="xml.BankServiceImpl">
<property name="customerService" ref="custService" />
<property name="billPaymentService" ref="billingService" />
</bean>
<bean class=”o.s.beans.factory.annotation.RequiredAnnotationBeanPostProcessor" />
如果我們沒有同時設置這兩個屬性,我們將在BankService配置中得到一個錯誤,因為兩者都是@Required。
我希望這有幫助!!
Same anwer by bmt - just adding here what i did to verify.
package com.requiredAnnotation;
import org.springframework.beans.factory.annotation.Required;
public class BankService {
private CustomerService customerService;
private BillPaymentService billPaymentService;
@Required
public void setCustomerService(CustomerService customerService) {
this.customerService = customerService;
}
@Required
public void setBillPaymentService(BillPaymentService billPaymentService) {
this.billPaymentService = billPaymentService;
}
public BillPaymentService getBillPaymentService() {
return billPaymentService;
}
public CustomerService getCustomerService() {
return customerService;
}
}
package com.requiredAnnotation;
public class CustomerService {
}
package com.requiredAnnotation;
public class BillPaymentService {
}
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<bean id="customerService" class="com.requiredAnnotation.CustomerService" />
<bean id="billPaymentService" class="com.requiredAnnotation.BillPaymentService" />
<bean id="bankService" class="com.requiredAnnotation.BankService">
<property name="customerService" ref="customerService" />
<!-- <property name="billPaymentService" ref="billPaymentService" /> -->
</bean>
<bean class="org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor" />
</beans>
package com.requiredAnnotation;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test {
public static void main(String[] args) {
ConfigurableApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:com/requiredAnnotation/beans-required.xml");
BankService bankService = applicationContext.getBean(BankService.class);
System.out.println("bankService got.");
System.out.println("getCustomerService - " + bankService.getCustomerService());
System.out.println("getBillPaymentService - " + bankService.getBillPaymentService());
}
}
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