Question

我正在为$("#selectServices option:selected").closest('td').attr('id');代码开发代码，到目前为止我开发了类似下面的代码，当我运行main方法时，我看到以下错误即将到来。

Injecting a prototype bean into a singleton bean

spring.xml

Jan 04, 2017 2:59:41 PM org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@6ed322: startup date [Wed Jan 04 14:59:41 IST 2017]; root of context hierarchy
Jan 04, 2017 2:59:41 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [spring.xml]
Constructor:: RequestProcessor instance created!
Constructor:: RequestProcessor instance created!
Request ID : 1212
Exception in thread "main" java.lang.AbstractMethodError: com.injection.testing.RequestProcessor.createValidator()Lcom/injection/testing/RequestValidator;
    at com.injection.testing.RequestProcessor.handleRequest(RequestProcessor.java:12)
    at com.injection.testing.MainDemo.main(MainDemo.java:13)

RequestProcessor.java

<!-- Lookup way  -->
    <bean id="requestProcessor" class="com.injection.testing.RequestProcessor" >
        <lookup-method name="getValidator" bean="validator" />
    </bean>

    <bean id="validator" class="com.injection.testing.RequestValidator" scope="prototype" />

RequestValidator.java

public abstract class RequestProcessor {
    private RequestValidator validator;

    public RequestProcessor(){
        System.out.println("Constructor:: RequestProcessor instance created!");
    }

    public void handleRequest(String requestId){
        System.out.println("Request ID : "+ requestId);
        RequestValidator validator = createValidator(); //here Spring will create new instance of prototype bean
        validator.validate(requestId);
    }

    public RequestValidator getValidator() {
        return validator;
    }

    public void setValidator(RequestValidator validator) {
        this.validator= validator;
    }

    protected abstract RequestValidator createValidator();
}

MainDemo.java

public class RequestValidator {
    private List<String> errorMessages = new ArrayList<String>();

    public RequestValidator() {
        System.out.println("Constructor:: RequestValidator instance created!");
    }

    // Validates the request and populates error messages
    public void validate(String requestId){
        System.out.println("RequestValidator :"+requestId);
    }

    public List<String> getErrorMessages() {
        return errorMessages;
    }
}

的pom.xml

public class MainDemo {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");

        //RequestValidator requestValidator = (RequestValidator) context.getBean("validator");

        RequestProcessor processor = (RequestProcessor) context.getBean("requestProcessor");
        processor.handleRequest("1212");
        System.out.println("------------------------");
        processor.handleRequest("1213");
    }
}

Answer 1

将您的spring.xml更新为以下

<bean id="requestProcessor" class="com.injection.testing.RequestProcessor">
    <lookup-method name="createValidator" bean="validator" />
</bean>

基本上，您需要在abstract xml属性中指定lookup-method方法名称的名称。

在更正配置后我得到了以下输出

2017年1月4日下午4:11:20 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh   信息：刷新org.springframework.context.support.ClassPathXmlApplicationContext@13c675d：启动日期[Wed Jan 04 16:11:20 IST 2017];上下文层次结构的根   2017年1月4日下午4:11:20 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO：从类路径资源[spring.xml]加载XML bean定义
构造函数:: RequestProcessor实例创建！
请求ID：1212
构造函数:: RequestValidator实例创建！
RequestValidator：1212
请求ID：1213
构造函数:: RequestValidator实例创建！
RequestValidator：1213

lookup方法 - 将原型bean注入单例bean问题

1 个答案: