Spring 学习——Spring注解——Autowiring(自动装配)

装配方式

方式一：默认

方式二：byName:根据属性名称自动装配。会查找Bean容器内部所有初始化的与属性名成相同的Bean,自动装配。（需要通过set方法注入，注入Bean的id名称需要和实体类的属性名称一致）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    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"
    default-autowire="byName">

    <bean id="autoService" class="com.jing.spring.autowiring.AutoWiringService"></bean>
    <bean id="autoWiringDao" class="com.jing.spring.autowiring.AutoWiringDao"></bean> 
 </beans>

ackage com.jing.spring.autowiring;

public class AutoWiringService {

    private AutoWiringDao autoWiringDao;

    public void setAutoWiringDao(AutoWiringDao autoWiringTestDao) {
        this.autoWiringDao = autoWiringTestDao;
    }

    public void autoService(String arg){
        System.out.println("AutoWiringService.autoService===="+arg);
        autoWiringDao.autoDao(arg);
    }
}

方式三：byType：根据类型自动装配。如果容器中存在一个与所需Bean类型相同的Bean，则自动装配。如果存在多个相同类型的Bean，报错。找不到相匹配的Bean，什么都不发生。（需要通过set方法注入！！！）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    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"
    default-autowire="byType">

    <bean class="com.jing.spring.autowiring.AutoWiringService"></bean>
    <bean class="com.jing.spring.autowiring.AutoWiringDao"></bean> 
 </beans>

Constructor：同byType相似。如果找不到匹配的Bean，报错。（需要通过构造方法注入，注入的Bean的id名称需要和实体类的属性名称一致！！！）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    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"
    default-autowire="constructor">

    <bean id="autoService" class="com.jing.spring.autowiring.AutoWiringService"></bean>
    <bean id="autoWiringDao" class="com.jing.spring.autowiring.AutoWiringDao"></bean>    
 </beans>

package com.jing.spring.autowiring;

public class AutoWiringService {

    private AutoWiringDao autoWiringDao;

    public AutoWiringService(AutoWiringDao autoWiringTestDao){
        this.autoWiringDao = autoWiringTestDao;
    }public void autoService(String arg){
        System.out.println("AutoWiringService.autoService===="+arg);

        autoWiringDao.autoDao(arg);
    }
}