《ApplicationContextAware》

1.ApplicationContextAware在项目中的应用

• 实现ApplicationContextAware接口，拿到应用上下文就可以拿到IOC里面的Bean，自己需注册到IOC

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component(value = "applicationContextUtils")
public class ApplicationContextUtils implements ApplicationContextAware {
    private static ApplicationContext context;//应用上下文
    //本类维护自己注册到IOC容器的Bean
    private static ApplicationContextUtils applicationContextUtils;
    @Value(value = "${spring.application.name}")
    private String applicationName;//应用名
    @Value(value = "${server.port}")
    private String serverPort;//服务器端口号
    @Value(value = "${server.servlet.context-path}")
    private String contextPath;//应用上下文访问前缀
    private static String serverInfo;//服务器信息
    private static final Class<ApplicationContextUtils> CLASS = ApplicationContextUtils.class;


    public static String getContextPath(){
        if (applicationContextUtils == null){
            applicationContextUtils = getBean(CLASS);
        }
        return applicationContextUtils.contextPath;
    }

    public static String getServerInfo(){
        if (serverInfo == null){
            if (applicationContextUtils == null){
                applicationContextUtils =  getBean(CLASS);
            }
            serverInfo = applicationContextUtils.applicationName+"_"+applicationContextUtils.serverPort;
        }
        return serverInfo;
    }

    public static String getApplicationName(){
        if (applicationContextUtils == null){
            applicationContextUtils = getBean(CLASS);
        }
        return applicationContextUtils.applicationName;
    }

    public static String getServerPort(){
        if (applicationContextUtils == null){
            applicationContextUtils = getBean(CLASS);
        }
        return applicationContextUtils.serverPort;
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        context = applicationContext;
    }

    public static ApplicationContext getContext(){
        return context;
    }

    public static<T> T getBean(Class<T> clazz){
        T result = null;
        if (context != null){
            result = context.getBean(clazz);
        }
        return result;
    }
}

2.聚合所有Service（结合ApplicationContextAware），实现无需注入，也可拿到Service，任意地方使用，带来更大的灵活性。

import com.wpq.service.IServiceA;
import com.wpq.service.IServiceB;
import com.wpq.service.IServiceC;

//玩转IOC
public class ServiceHolder {
    //全部为接口
    private static IServiceA serviceA;
    private static IServiceB serviceB;
    private static IServiceC serviceC;

    public static IServiceA getServiceA() {

        if (serviceA == null){
            serviceA = ApplicationContextUtils.getBean(IServiceA.class);
        }
        return serviceA;
    }

    public static IServiceB getServiceB() {
        if (serviceB == null){
            serviceB = ApplicationContextUtils.getBean(IServiceB.class);
        }
        return serviceB;
    }

    public static IServiceC getServiceC() {
        if (serviceC == null){
            serviceC = ApplicationContextUtils.getBean(IServiceC.class);
        }
        return serviceC;
    }
}

本文地址：https://blog.csdn.net/weixin_43766298/article/details/107394847