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  • 从头认识Spring-2.3 注解装配-@autowired(4)-required(2)

    这一章节我们来继续具体讨论一下@autowired里面的參数required。在多构造器注入的情况。

    1.domain(重点)

    蛋糕类:

    package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10;
    
    public class Cake {
    
    	private String name = "";
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    }
    

    厨师类:

    package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10;
    
    import org.springframework.beans.factory.annotation.Autowired;
    
    public class Chief {
    	private Cake cake = null;
    
    	private Oven oven = null;
    
    	@Autowired(required = false)
    	public Chief(Cake cake) {
    		this.cake = cake;
    	}
    
    	@Autowired(required = false)
    	public Chief(Cake cake, Oven oven) {
    		this.cake = cake;
    		this.oven = oven;
    	}
    
    	private String name = "";
    
    	public String getName() {
    		return name;
    	}
    
    	public Cake makeOneCake() {
    		if (cake != null) {
    			System.out.println(getName() + " use " + oven.getName() + " and make " + cake.getName());
    		} else {
    			System.out.println("null");
    		}
    		return cake;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    }
    

    厨师类这里须要注意的是,当出现多构造器注入的情况,尽管我们都能够使用@autowired标签。可是须要把required都弄成是false,不然抛异常

    还有的是,当出现多构造器注入时。注入成功的是注入对象最多的那个构造器,也就是上面有两个參数的那个


    烤炉类:(又一次引入)

    package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10;
    
    public class Oven {
    	private String name = "";
    
    	@Override
    	public String toString() {
    		return name;
    	}
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    }
    


    2.測试类:(不变)

    package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10;
    
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.ApplicationContext;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(locations = {
    		"/com/raylee/my_new_spring/my_new_spring/ch02/topic_1_10/ApplicationContext-test.xml" })
    public class ChiefTest {
    
    	@Autowired
    	private ApplicationContext applicationContext;
    
    	@Test
    	public void testChief() {
    		Chief jack = applicationContext.getBean(Chief.class);
    		jack.makeOneCake();
    	}
    }
    


    3.配置文件

    <?

    xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:util="http://www.springframework.org/schema/util" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"> <bean id="blueberryCheeseCake" class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10.Cake" p:name="blueberryCheeseCake" scope="prototype" /> <bean id="bigOven" class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10.Oven" p:name="bigOven" /> <bean id="jack" class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10.Chief" p:name="jack" /> </beans>



    測试输出:

    jack use bigOven and make blueberryCheeseCake


    总结:这一章节我们主要讨论了@autowired里面的參数required。


    文件夹:http://blog.csdn.net/raylee2007/article/details/50611627 

    我的github:https://github.com/raylee2015/my_new_spring


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  • 原文地址:https://www.cnblogs.com/gccbuaa/p/7161939.html
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