# ApplicationContextAware
当一个类实现了这个接口（ApplicationContextAware）之后，这个类就可以方便获得 ApplicationContext 中的所有 bean。换句话说，就是这个类可以直接获取 Spring 配置文件中，所有有引用到的 Bean 对象。
package com.cmcc.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;
/**
* 获取存储在静态变量中的 ApplicationContext
* @return
*/
public static ApplicationContext getApplicationContext() {
assertContextInjected();
return applicationContext;
}
/**
* 从静态变量 applicationContext 中获取 Bean，自动转型成所赋值对象的类型
* @param name
* @param <T>
* @return
*/
public static <T> T getBean(String name) {
assertContextInjected();
return (T) applicationContext.getBean(name);
}
/**
* 从静态变量 applicationContext 中获取 Bean，自动转型成所赋值对象的类型
* @param clazz
* @param <T>
* @return
*/
public static <T> T getBean(Class<T> clazz) {
assertContextInjected();
return applicationContext.getBean(clazz);
}
/**
* 实现 DisposableBean 接口，在 Context 关闭时清理静态变量
* @throws Exception
*/
public void destroy() throws Exception {
logger.debug("清除 SpringContext 中的 ApplicationContext: {}", applicationContext);
applicationContext = null;
}
/**
* 实现 ApplicationContextAware 接口，注入 Context 到静态变量中
* @param applicationContext
* @throws BeansException
*/
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
SpringContext.applicationContext = applicationContext;
}
/**
* 断言 Context 已经注入
*/
private static void assertContextInjected() {
Validate.validState(applicationContext != null, "applicationContext 属性未注入，请在 spring-context.xml 配置中定义 SpringContext");
}
}
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还需要在 spring-context.xml 配置文件中装配 <bean id="springContext" class="com.cmcc.leeshop.commons.context.SpringContext" />;
注意：请将该 Bean 放在配置顶部，否则使用时会报错
# POM
需要在 pom.xml 中增加 org.apache.commons:commons-lang3 依赖
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.5</version>
</dependency>
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# 附：完整的 POM 文件
截止目前所学知识点，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.cmcc</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>
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