學(xué)習(xí)完整課程請(qǐng)移步 互聯(lián)網(wǎng) Java 全棧工程師

當(dāng)一個(gè)類實(shí)現(xiàn)了這個(gè)接口（ApplicationContextAware）之后勋拟，這個(gè)類就可以方便獲得 ApplicationContext 中的所有 bean。換句話說(shuō)妈候，就是這個(gè)類可以直接獲取 Spring 配置文件中敢靡，所有有引用到的 Bean 對(duì)象。

package com.funtl.leeshop.commons.context;

import org.apache.commons.lang3.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

public class SpringContext implements ApplicationContextAware, DisposableBean {

    private static final Logger logger = LoggerFactory.getLogger(SpringContext.class);

    private static ApplicationContext applicationContext;

    /**
     * 獲取存儲(chǔ)在靜態(tài)變量中的 ApplicationContext
     * @return
     */
    public static ApplicationContext getApplicationContext() {
        assertContextInjected();
        return applicationContext;
    }

    /**
     * 從靜態(tài)變量 applicationContext 中獲取 Bean苦银，自動(dòng)轉(zhuǎn)型成所賦值對(duì)象的類型
     * @param name
     * @param <T>
     * @return
     */
    public static <T> T getBean(String name) {
        assertContextInjected();
        return (T) applicationContext.getBean(name);
    }

    /**
     * 從靜態(tài)變量 applicationContext 中獲取 Bean啸胧，自動(dòng)轉(zhuǎn)型成所賦值對(duì)象的類型
     * @param clazz
     * @param <T>
     * @return
     */
    public static <T> T getBean(Class<T> clazz) {
        assertContextInjected();
        return applicationContext.getBean(clazz);
    }

    /**
     * 實(shí)現(xiàn) DisposableBean 接口，在 Context 關(guān)閉時(shí)清理靜態(tài)變量
     * @throws Exception
     */
    public void destroy() throws Exception {
        logger.debug("清除 SpringContext 中的 ApplicationContext: {}", applicationContext);
        applicationContext = null;
    }

    /**
     * 實(shí)現(xiàn) ApplicationContextAware 接口幔虏，注入 Context 到靜態(tài)變量中
     * @param applicationContext
     * @throws BeansException
     */
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        SpringContext.applicationContext = applicationContext;
    }

    /**
     * 斷言 Context 已經(jīng)注入
     */
    private static void assertContextInjected() {
        Validate.validState(applicationContext != null, "applicationContext 屬性未注入纺念，請(qǐng)?jiān)?spring-context.xml 配置中定義 SpringContext");
    }
}

還需要在 spring-context.xml 配置文件中裝配 <bean id="springContext" class="com.funtl.leeshop.commons.context.SpringContext" />;

POM

需要在 pom.xml 中增加 org.apache.commons:commons-lang3 依賴

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.5</version>
</dependency>

附：完整的 POM 文件

截止目前所學(xué)知識(shí)點(diǎn)，完整的 pom.xml 如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.funtl</groupId>
    <artifactId>leeshop</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <dependencies>
        <!-- Spring Begin -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.3.17.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.3.17.RELEASE</version>
        </dependency>
        <!-- Spring End -->

        <!-- Servlet Begin -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <!-- Servlet End -->

        <!-- Log Begin -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jul-to-slf4j</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <!-- Log End -->

        <!-- Commons Begin -->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.5</version>
        </dependency>
        <!-- Commons End -->
    </dependencies>
</project>