【Spring-Framework】在Spring MVC中奇怪的@Autowire

spring容器

下面是service容器

<?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:property-placeholder location="classpath:log4j.properties"/>

    <bean id="account" class="domin.Account">
        <property name="name" value="dom"/>
    </bean>
</beans>

對應的domain類

package domin;

public class Account {
    String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "Account{" +
                "name='" + name + '\'' +
                '}';
    }
}

Spring MVC容器

不使用註解掃描

容器配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       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
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">


    <bean id="controller" class="controller.MyConctroller">
    </bean>

    <mvc:annotation-driven/>

控制器代碼

package controller;

import domin.Account;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@RequestMapping("myController")
public class MyConctroller {

    private Account account;

    @Autowired
    @Qualifier("account")
    public void setAccount(Account account) {
        this.account = account;
    }

    @RequestMapping("/findAll")
    public String findAll(Model model){
        System.out.println("表現層：查詢所有賬戶...");
        System.out.println(this.account);
        return "list";
    }
}

上面的代碼中對於account這個對象的自動注入會失敗，spring mvc容器需要修改成如下，從而進行手動注入

<bean id="controller" class="controller.MyConctroller">
        <property name="account" ref="account"/>
    </bean>

使用註解掃描

容器配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       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
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">
    <!--開啓註解掃描，只掃描Controller註解-->
    <context:component-scan base-package="controller"/>

</beans>

控制器加上@Controller

package controller;

import domin.Account;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("myController")
public class MyConctroller {

    private Account account;

    @Autowired
    @Qualifier("account")
    public void setAccount(Account account) {
        this.account = account;
    }

    @RequestMapping("/findAll")
    public String findAll(Model model){
        System.out.println("表現層：查詢所有賬戶...");
        System.out.println(this.account);
        return "list";
    }
}

這樣對於account的自動注入就會成功，原因不明

附web.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <display-name>Archetype Created Web Application</display-name>

    <!--配置Spring的監聽器，默認只加載WEB-INF目錄下的applicationContext.xml配置文件-->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <!--設置配置文件的路徑-->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>

    <!--配置前端控制器-->
    <servlet>
        <servlet-name>dispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--加載springmvc.xml配置文件-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
        <!--啓動服務器，創建該servlet-->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>