Content Table
2017-04-02

Autowired 注入

@Autowired 是基于类型的注入，Spring 会在 IoC 容器里查找类型匹配的 Bean 注入。

spring-beans.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       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:component-scan base-package="com.xtuer.beans"/>

    <bean class="com.xtuer.beans.Door"/>
</beans>

Door

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package com.xtuer.beans;

public class Door {
    private String description;

    public Door() {
        description = "Default Door";
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}

House

使用 @Autowired 注入 door。

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package com.xtuer.beans;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

// 生成的 Bean 的 ID 是 house
@Component
public class House {
    private String description;

    @Autowired
    private Door door;

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public Door getDoor() {
        return door;
    }

    public void setDoor(Door door) {
        this.door = door;
    }
}

测试

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import com.xtuer.beans.House;
import com.xtuer.util.CommonUtils;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class ComponentScanTest {
    private static ApplicationContext context;

    @BeforeClass
    public static void setup() {
        context = new ClassPathXmlApplicationContext("spring-beans.xml");
    }

    @Test
    public void test() {
        House house1 = context.getBean(House.class);
        CommonUtils.output(house1);
    }
}

输出

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{
    "description" : null,
    "door" : {
        "description" : "Default Door"
    }
}