一个接口多个实现类

一、以静态变量保存Spring ApplicationContext, 可在任何代码任何地方任何时候取出ApplicaitonContext。适用于根据数据库的配置取出对应定时任务的实现类

package com.wy.SpringBean;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
import org.springframework.util.Assert;

/**
 * @description:以静态变量保存Spring ApplicationContext, 可在任何代码任何地方任何时候取出ApplicaitonContext，
 * 适用于根据数据库的配置取出对应定时任务的实现类
 **/

@Component
public class SpringContextHolder implements ApplicationContextAware, DisposableBean {

    private static ApplicationContext applicationContext = null;

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

    /**
     * 取得存储在静态变量中的ApplicationContext.
     */
    public static ApplicationContext getApplicationContext() {
        assertContextInjected();
        return applicationContext;
    }

    /**
     * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
        assertContextInjected();
        return (T) applicationContext.getBean(name);
    }

    /**
     * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    public static <T> T getBean(Class<T> requiredType) {
        assertContextInjected();
        return applicationContext.getBean(requiredType);
    }

    /**
     * 清除SpringContextHolder中的ApplicationContext为Null.
     */
    public static void clearHolder() {
        logger.debug("清除SpringContextHolder中的ApplicationContext:" + applicationContext);
        applicationContext = null;
    }

    /**
     * 实现ApplicationContextAware接口, 注入Context到静态变量中.
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) {
        logger.debug("注入ApplicationContext到SpringContextHolder:" + applicationContext);

        if (SpringContextHolder.applicationContext != null) {
            logger.warn("SpringContextHolder中的ApplicationContext被覆盖, 原有ApplicationContext为:"
                    + SpringContextHolder.applicationContext);
        }

        SpringContextHolder.applicationContext = applicationContext;
    }

    /**
     * 实现DisposableBean接口, 在Context关闭时清理静态变量.
     */
    @Override
    public void destroy() throws Exception {
        SpringContextHolder.clearHolder();
    }

    /**
     * 检查ApplicationContext不为空.
     */
    private static void assertContextInjected() {
        Assert.state(applicationContext != null,
                "applicaitonContext属性未注入, 请在applicationContext.xml中定义SpringContextHolder.");
    }


}

二、定义接口

public interface TestInterface {

    void testInter(String str);
}

三、定义两个个实现类

@Service("testImp01")
public class testImp01 implements TestInterface{
    @Override
    public void testInter(String str) {
        System.out.println("testImp01:"+str);
    }
}

@Service("testImp02")
public class testImp02 implements TestInterface{
    @Override
    public void testInter(String str) {
        System.out.println("testImp02:"+str);
    }
}

四、定义controller

@RestController
public class TestController {



    @RequestMapping("test01")
    public void test01() {
        TestInterface testInterface = SpringContextHolder.getBean("testImp01");
        testInterface.testInter("01");
    }
    @RequestMapping("test02")
    public void test02() {
        TestInterface testInterface = SpringContextHolder.getBean("testImp02");
        testInterface.testInter("02");
    }

}

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