spring4笔记----使用装配注入合作者Bean的三种方式

时间:2023-11-28 19:49:26
  1. no :不自动装配
  2. byName :id(name)与setter方法去set前缀,并小写首字母后同名的Bean完成注入,如有多个匹配则抛异常
  3. byType :spring容器找全部bean,如果找到单单一个bean类型和setter方法形参类型匹配的则完成注入,如有多个匹配则抛异常

两个名字相同抛异常情况例子:

Exception in thread "main" org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: Bean name 'd' is already used in this <beans> element
Offending resource: class path resource [beans.xml] at org.springframework.beans.factory.parsing.FailFastProblemReporter.error(FailFastProblemReporter.java:70)
at org.springframework.beans.factory.parsing.ReaderContext.error(ReaderContext.java:85)
at org.springframework.beans.factory.parsing.ReaderContext.error(ReaderContext.java:80)
at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.error(BeanDefinitionParserDelegate.java:301)
at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.checkNameUniqueness(BeanDefinitionParserDelegate.java:511)
at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseBeanDefinitionElement(BeanDefinitionParserDelegate.java:457)
at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseBeanDefinitionElement(BeanDefinitionParserDelegate.java:429)
at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.processBeanDefinition(DefaultBeanDefinitionDocumentReader.java:299)
at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.parseDefaultElement(DefaultBeanDefinitionDocumentReader.java:190)
at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.parseBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:169)
at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.doRegisterBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:142)
at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.registerBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:94)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.registerBeanDefinitions(XmlBeanDefinitionReader.java:508)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:392)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:336)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:304)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:181)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:217)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:188)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:252)
at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:127)
at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:93)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:129)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:612)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:513)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
at com.ij34.bean.test.main(test.java:12)

接口

package com.ij34.interfaces;

public interface dog {
public String run();
}
package com.ij34.interfaces;

public interface people {
public void test();
}

对象

package com.ij34.servce;

import com.ij34.interfaces.dog;

public class Dog implements dog{
private String name; public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} @Override
public String run() {
// TODO Auto-generated method stub
return "我是一只阿拉斯加狗,名字叫:"+getName();
} }
package com.ij34.servce;

import com.ij34.interfaces.dog;

public class Dog2 implements dog{
private String name; public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} @Override
public String run() {
// TODO Auto-generated method stub
return "我是一只哈奇士狗,名字叫:"+getName();
} }
package com.ij34.servce;

import com.ij34.interfaces.dog;
import com.ij34.interfaces.people; public class People implements people{
private dog d; public dog getD() {
return d;
} public void setD(dog d) {
this.d = d;
} @Override
public void test() {
// TODO Auto-generated method stub
System.out.println("我是程序员:"+getD().run());
} }

<?xml version="1.0" encoding="GBK"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.3.xsd">
<bean id="chinese" class="com.ij34.servce.People" autowire="byName" /> <!-- 或者byType -->
<bean name="d" class="com.ij34.servce.Dog" >
<property name="name" value="牛仔1"></property>
</bean> <bean name="d1" class="com.ij34.servce.Dog2" > <!-- 多个,另外的里面添加: autowire-candidate="false"-->
<property name="name" value="大哈2狗"></property>
</bean>
</beans>

运行

package com.ij34.bean;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.ij34.servce.People; public class test { public static void main(String[] args) {
// TODO Auto-generated method stub
@SuppressWarnings("resource")
ApplicationContext app=new ClassPathXmlApplicationContext("beans.xml");
People p=app.getBean("chinese", People.class);
p.test();
} }

spring4笔记----使用装配注入合作者Bean的三种方式