问题描述
我通过构造器注入，并且给构造参数指定了类型，但是运行时报错。代码： package com.alpha.spring.ch4;import org.springframework.beans.factory.xml.XmlBeanFactory;import org.springframework.core.io.FileSystemResource;public class ConstructorConfusion {private String message;public ConstructorConfusion(String message, int number) {System.out.println("ConstructorConfusion(String message, int number) is called");this.message = message + Integer.toString(number);}public String toString() {return message;}public static void main(String[] args) {XmlBeanFactory factory = new XmlBeanFactory(new FileSystemResource("applicationContext.xml"));ConstructorConfusion cc = (ConstructorConfusion)factory.getBean("constructorConfusion");System.out.println(cc);}}xml配置文件：<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"><beans><bean id="constructorConfusion" class="com.alpha.spring.ch4.ConstructorConfusion"><constructor-arg index="0" type="String"><value>hello world</value></constructor-arg><constructor-arg index="1" type="int"><value>20</value></constructor-arg></bean></beans>运行代码时控制台输出如下错误信息：log4j:WARN No appenders could be found for logger (org.springframework.core.CollectionFactory).log4j:WARN Please initialize the log4j system properly.Exception in thread "main" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'constructorConfusion' defined in file [E:test_workspacespringapplicationContext.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [java.lang.String]: Ambiguous constructor argument types - did you specify the correct bean references as constructor arguments?at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createArgumentArray(AbstractAutowireCapableBeanFactory.java:796)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:673)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:358)at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:233)at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:145)at com.alpha.spring.ch4.ConstructorConfusion.main(ConstructorConfusion.java:17)哪位请告诉我哪里不对？
解决方案
1, String加上包名:<bean id="constructorConfusion" class="com.alpha.spring.ch4.ConstructorConfusion"><constructor-arg index="0" type="java.lang.String"><value>hello world</value></constructor-arg><constructor-arg index="1" type="int"><value>20</value></constructor-arg></bean>2, 指定了index可以直接把type去掉<bean id="constructorConfusion" class="com.alpha.spring.ch4.ConstructorConfusion"><constructor-arg index="0"><value>hello world</value></constructor-arg><constructor-arg index="1"><value>20</value></constructor-arg></bean>
解决方案二：
alert('test.');
解决方案三：
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