Spring常用工具类（ApplicationContextAware、DisposableBean、InitializingBean）

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 由于各种原因，可能存在诸多不足，欢迎斧正！

1、ApplicationContextAware

        org.springframework.context.ApplicationContextAware
　   实现该接口的类，可以在spring容器初始化的时候调用setApplicationContext方法，从而获得ApplicationContext中的所有bean。

public class SpringUtils implements ApplicationContextAware {

    private static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        SpringUtils.applicationContext = applicationContext;
        synchronized (SpringUtils.class) {
            SpringUtils.class.notifyAll();
        }
    }

    private static void checkForInitialized() {
        if (applicationContext == null) {
            synchronized (SpringUtils.class) {
                if (applicationContext == null) {
                    try {
                        SpringUtils.class.wait();
                    } catch (InterruptedException e) {
                        Thread.currentThread().interrupt();
                    }
                }
            }
        }
    }

    @SuppressWarnings("unchecked")
    public static <T> T bean(String name) {
        checkForInitialized();
        return (T) applicationContext.getBean(name);
    }

    public static <T> T bean(Class<T> clazz) {
        checkForInitialized();
        return applicationContext.getBean(clazz);
    }

    public static <T> Map<String, T> beans(Class<T> clazz) {
        checkForInitialized();
        return applicationContext.getBeansOfType(clazz);
    }

}

public class SpringUtils implements ApplicationContextAware {
private static ApplicationContext applicationContext;

@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    SpringUtils.applicationContext = applicationContext;
    synchronized (SpringUtils.class) {
        SpringUtils.class.notifyAll();
    }
}

private static void checkForInitialized() {
    if (applicationContext == null) {
        synchronized (SpringUtils.class) {
            if (applicationContext == null) {
                try {
                    SpringUtils.class.wait();
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                }
            }
        }
    }
}

@SuppressWarnings("unchecked")
public static <T> T bean(String name) {
    checkForInitialized();
    return (T) applicationContext.getBean(name);
}

public static <T> T bean(Class<T> clazz) {
    checkForInitialized();
    return applicationContext.getBean(clazz);
}

public static <T> Map<String, T> beans(Class<T> clazz) {
    checkForInitialized();
    return applicationContext.getBeansOfType(clazz);
}

}

２、DisposableBean、InitializingBean
　　import org.springframework.beans.factory.DisposableBean;
　　import org.springframework.beans.factory.InitializingBean;
　　接口实现初始化方法和销毁前操作主要有下面３种方法：
　2.1、第一种：通过@PostConstruct 和 @PreDestroy 方法 实现初始化和销毁bean之前进行的操作;
　2.2、第二种是：通过 在xml中定义init-method 和  destory-method方法;
　2.3、第三种是： 通过bean实现InitializingBean和 DisposableBean接口;

public class PersonService  implements InitializingBean,DisposableBean{

    private String  message;

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    @Override
    public void destroy() throws Exception {
        // TODO Auto-generated method stub
        System.out.println("I'm  init  method  using implements InitializingBean interface...."+message);

    }

    @Override
    public void afterPropertiesSet() throws Exception {
        // TODO Auto-generated method stub
        System.out.println("I'm  init  method  using implements DisposableBean interface...."+message);

    }

}

public class PersonService  implements InitializingBean,DisposableBean{
private String  message;

public String getMessage() {
	return message;
}

public void setMessage(String message) {
	this.message = message;
}

@Override
public void destroy() throws Exception {
	// TODO Auto-generated method stub
	System.out.println("I'm  init  method  using implements InitializingBean interface...."+message);
	
}

@Override
public void afterPropertiesSet() throws Exception {
	// TODO Auto-generated method stub
	System.out.println("I'm  init  method  using implements DisposableBean interface...."+message);
	
}

}

　　路漫漫其修远兮，很多时候感觉想法比较幼稚。首先东西比较简单，其次工作也比较忙，还好周末可以抽时间处理这个。由于相关知识积累有限，欢迎大家提意见斧正，在此表示感谢！后续版本会持续更新…