Spring @Required和@Mandatory注释

这是 BeanClass.java

package com.practice.spring;

import org.springframework.beans.factory.annotation.Required;

import com.apress.springrecipes.sequence.Mandatory;

public class BeanClass {

    private int count;
    private String prefix;

    public BeanClass() {
        System.out.println("Default Constructor");
    }

    public BeanClass(int count, String prefix) {
        this.count = count;
        this.prefix = prefix;
        System.out.println(prefix+count);
    }

    @Required
    public void setCount(int count) {
        this.count = count;
    }

    @Mandatory
    public void setPrefix(String prefix) {
        this.prefix = prefix;
    }

    @Override
    public String toString() {
        return prefix+count;
    }

}

这是 beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       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/context
            http://www.springframework.org/schema/context/spring-context.xsd">

    <context:annotation-config />

    <bean id="beanClass1"
          class="com.practice.spring.BeanClass">
        <property name="count" value="1" />
        <property name="prefix" value="Bean" />
    </bean>
    <bean id="beanClass2"
          class="com.practice.spring.BeanClass">
        <constructor-arg value="2" />
        <constructor-arg value="Bean" />
    </bean>
    <bean id="beanClass3"
          class="com.practice.spring.BeanClass">
        <constructor-arg>
            <value>3</value>
        </constructor-arg>
        <constructor-arg>
            <value>Bean</value>
        </constructor-arg>
    </bean>
</beans>

这就是我实例化上下文的方式 .

ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");

Problem:

count属性是必需的，前缀是必需的 . 如果你看到 beanClass2 我正在通过构造函数设置属性，并且在 beanClass3 中也是如此

但是当我执行代码时，它会抛出异常 . 令我困惑的重要事情是：

线程“main”中的异常org.springframework.beans.factory.BeanCreationException：在类路径资源[beans.xml]中定义的名称为'beanClass2'的bean创建错误：bean的初始化失败;嵌套异常是org.springframework.beans.factory.BeanInitializationException：bean'beanClass2'需要属性'count'

它打印Default Constructor＆Bean2 . 我也在这里粘贴整个堆栈跟踪：

2014年12月9日下午8:47:33 org.springframework.context.support.AbstractApplicationContext prepareRefresh INFO：刷新org.springframework.context.support.ClassPathXmlApplicationContext@1a71e93：启动日期[Tue Dec 09 20:47:33 PKT 2014] ; org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions INFO：从类路径资源加载XML bean定义[beans.xml] 2014年12月9日8:47:33上下文层次结构根据2014年12月9日8:47:33 PM org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons INFO：在org.springframework.beans.factory.support.DefaultListableBeanFactory@4aed64中预实例化单例：定义bean [org.springframework.context.annotation.internalConfigurationAnnotationProcessor，org.springframework .context.annotation.internalAutowiredAnnotationProcessor，org.springframework.context.annotation.internalRequiredAnnotationProcessor，org.springframework.context.annotation.internalCommonAnnotationProcessor，beanClass1，beanClass2，beanClass3];工厂层次结构的根默认构造函数Bean2 2014年12月9日8:47:33 org.springframework.beans.factory.support.DefaultSingletonBeanRegistry destroySingletons信息：在org.springframework.beans.factory.support.DefaultListableBeanFactory@4aed64中销毁单例：定义bean [org.springframework.context.annotation.internalConfigurationAnnotationProcessor，org.springframework.context.annotation.internalAutowiredAnnotationProcessor，org.springframework.context.annotation.internalRequiredAnnotationProcessor，org.springframework.context.annotation.internalCommonAnnotationProcessor，beanClass1，beanClass2，beanClass3];工厂层次结构的根在线程“main”中的异常org.springframework.beans.factory.BeanCreationException：在类路径资源[beans.xml]中定义的名称为'beanClass2'的bean创建错误：bean的初始化失败;嵌套异常是org.springframework.beans.factory.BeanInitializationException：org.springframework上的org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean（AbstractAutowireCapableBeanFactory.java:527）中bean'beanClass2'需要属性'count' . bean.factory.support.AbstractAutowireCapableBeanFactory.createBean（AbstractAutowireCapableBeanFactory.java:456）位于org.springframework.beans.factory.support.DefaultSingletonBeanRegistry的org.springframework.beans.factory.support.AbstractBeanFactory $ 1.getObject（AbstractBeanFactory.java:291） .getSingleton（DefaultSingletonBeanRegistry.java:222）org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean（AbstractBeanFactory.java:288）org.springframework.beans.factory.support.AbstractBeanFactory.getBean（AbstractBeanFactory.java:190） ）org.springfram上的org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons（DefaultListableBeanFactory.java:563） eg.sptext.support.AbstractApplicationContext.finishBeanFactoryInitialization（AbstractApplicationContext.java:872）位于org.springframework.context.support.ClassPathXmlApplicationContext的org.springframework.context.support.AbstractApplicationContext.refresh（AbstractApplicationContext.java:423） . （ClassPathXmlApplicationContext.java ：139）atg.springframework.context.support.ClassPathXmlApplicationContext . （ClassPathXmlApplicationContext.java:83）at com.practice.spring.Main.main（Main.java:13）引起：org.springframework.beans.factory.BeanInitializationException ：bean'beanClass2'所在的属性'count'是必需的org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor.postProcessPropertyValues（RequiredAnnotationBeanPostProcessor.java:149）位于org.springframework.beans.factory的org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean（AbstractAutowireCapableBeanFactory.java:1064） . support.AbstractAutowireCapableBeanFactory.doCreateBean（AbstractAutowireCapableBeanFactory.java:517）... 11更多