SpringBoot 使用ApplicationContext 及 getbean的两种方式

╰半夏微凉° 2023-05-31 10:08 1阅读 0赞

第一种：容器加载时设置

public class ProxyApplication {
    	public static void main(String[] args) {
    		ApplicationContext applicationContext = SpringApplication.run(ProxyApplication.class, args);
    		SpringContextUtil.setApplicationContext(applicationContext);
    	}
    }

实例化SpringContextUtil

public class SpringContextUtil {
    
        // Spring应用上下文环境
        private static ApplicationContext applicationContext;
    
        /**
         * 实现ApplicationContextAware接口的回调方法，设置上下文环境
         */
        public static void setApplicationContext(ApplicationContext applicationContext)throws BeansException  {
            SpringContextUtil.applicationContext = applicationContext;
        }
    
        public static ApplicationContext getApplicationContext() {
            return applicationContext;
        }
    
        /**
         *  根据beanId返回Spring中的实例
         * @Date 2019-08-07 17:36
         * @param
         * @return
         **/
        public static Object getBean(String beanId) throws BeansException {
            return applicationContext.getBean(beanId);
        }
    }

使用场景：实体中初始化信息，加载类信息到容器中

@Data
    @Configuration
    public class AutoLogonConfig {
    	private boolean autoLogon = false;
    	
    	private String loginName = "";
    	
    	private String password = "";
    
    	private String ip = "";
    	
    	public AutoLogonConfig(@Value("${loginFilePath}") String  loginFilePath){
    		Yaml yaml = new Yaml();
    		InputStream in;
    		try {
    			File file = new File(loginFilePath);
    			in = new FileInputStream(file);
    			Map map = (Map) yaml.load(in);
    			Pub.loginFilePath = loginFilePath;
    			this.autoLogon=(boolean) map.get("autoLogon");
    			this.loginName=(String) map.get("loginName");
    			this.password=(String) map.get("password");
    			this.ip=(String) map.get("ip");
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    }

AutoLogonConfig autoLogonConfig = (AutoLogonConfig) SpringContextUtil.getBean("autoLogonConfig");

第二种：继承ApplicationContextAware

@Component
    public class ApplicationContextUtil implements ApplicationContextAware {
    
        /**
         * 获取bean
         * @param name
         * @return
         * @throws BeansException
         */
        public static Object getBean(String name) throws BeansException {
            Object o = applicationContext.getBean(name);
            return o;
        }
        private static ApplicationContext applicationContext;
    
        /**
         * Set the ApplicationContext that this object runs in.
         * Normally this call will be used to initialize the object.
         * <p>Invoked after population of normal bean properties but before an init callback such
         * as {@link InitializingBean#afterPropertiesSet()}
         * or a custom init-method. Invoked after {@link ResourceLoaderAware#setResourceLoader},
         * {@link ApplicationEventPublisherAware#setApplicationEventPublisher} and
         * {@link MessageSourceAware}, if applicable.
         *
         * @param applicationContext the ApplicationContext object to be used by this object
         * @throws ApplicationContextException in case of context initialization errors
         * @throws BeansException              if thrown by application context methods
         * @see BeanInitializationException
         */
        @Override
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
            ApplicationContextUtil.applicationContext = applicationContext;
        }
    
        public static ApplicationContext getApplicationContext(){
            return applicationContext;
        }
    
    
    }

使用场景：需要通过反射机制

public Map<String,String> functionOperation(ProxyParamDTO params, OperationEntity operationEntity) throws Exception{
            Map<String,String> m = null;
            String className;
            String functionName;
            // [0]:ClassName, [1];functionName
            String[] arr = getFunctionName(operationEntity);
            className = arr[0];
            functionName = arr[1];
            operationEntity.setParamDto(params);
            try {
                // getBean
                Object o = ApplicationContextUtil.getBean(className);
                // getClass
                Class<?> clazz = o.getClass();
                // getMethod by class
                Method method = clazz.getMethod(functionName, OperationEntity.class);
                // execute method and get returned value
                m = (HashMap) method.invoke(o, operationEntity);
                System.out.println(operationEntity.getOperationOrder() + " : " + method.getName());
            } catch (NoSuchMethodException | BeansException e) {
                otherFunctions(operationEntity, arr);
            } catch (IllegalAccessException | InvocationTargetException e) {
                e.printStackTrace();
                throw e;
            }
            return m;
        }