Spring手动获取bean的四种方式
作者:hvige
本文主要介绍了Spring手动获取bean的四种方式,包括BeanFactoryPostProcessor接口,ApplicationContextAware接口,注解 @PostConstruct 初始化时获取,启动类ApplicationContext获取这四种方法,感兴趣的可以了解一下
一、实现BeanFactoryPostProcessor接口
@Component public class SpringUtil implements BeanFactoryPostProcessor { private static ConfigurableListableBeanFactory beanFactory; public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException { this.beanFactory = beanFactory; } /** * 通过name获取 Bean对象 * @param name * @return Object 一个以所给名字注册的bean实例 */ public static <T> T getBean(String name) { return (T) beanFactory.getBean(name); } /** * 通过class获取Bean对象 * @param clazz * @param <T> * @return */ public static <T> T getBean(Class<T> clazz){ return beanFactory.getBean(clazz); } /** * 如果BeanFactory包含一个与所给名称匹配的bean对象,则返回true * @param name * @return */ public static boolean containsBean(String name){ return beanFactory.containsBean(name); } /** * 判断bean对象是一个singleton还是一个prototype * @param name * @return * @throws NoSuchBeanDefinitionException */ public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException{ return beanFactory.isSingleton(name); } /** * 通过 name获取 bean 的类型 * @param name * @return * @throws NoSuchBeanDefinitionException */ public static Class<?> getType(String name) throws NoSuchBeanDefinitionException{ return beanFactory.getType(name); } /** * 通过 name 获取 bean定义的别名 * @param name * @return */ public static String[] getAliases(String name){ return beanFactory.getAliases(name); } }
二、实现ApplicationContextAware接口
@Component public class BeanUtil implements ApplicationContextAware { private static ApplicationContext applicationContext; @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { BeanUtil.applicationContext = applicationContext; } /** * 获取applicationContext * * @return */ public static ApplicationContext getApplicationContext() { return applicationContext; } /** * 通过name获取 Bean对象 * * @param name * @return */ public static Object getBean(String name) { return getApplicationContext().getBean(name); } /** * 通过class获取Bean对象 * @param clazz * @param <T> * @return */ public static <T> T getBean(Class<T> clazz) { return getApplicationContext().getBean(clazz); } /** * 通过name和Class返回指定的Bean对象 * * @param name * @param clazz * @param <T> * @return */ public static <T> T getBean(String name, Class<T> clazz) { return getApplicationContext().getBean(name, clazz); } /** * 获取当前的环境配置 * @return */ public static String[] getActiveProfiles(){ return getApplicationContext().getEnvironment().getActiveProfiles(); } }
三、注解 @PostConstruct 初始化时获取
@Component public class BeanStatic { @Autowired private TestService testService; @Autowired private static TestService staticTestService; /** * 用于在依赖关系注入完成之后需要执行的方法上 * 执行任何初始化操作 */ @PostConstruct public void init() { // 初始化时把testService对象赋值给当前类定义的静态变量 staticTestService = testService; } // 在当前类调用业务接口 public static String getTest() { return staticTestService.test(); } }
四、通过启动类ApplicationContext获取
@SpringBootApplication public class WebApplication { public static ConfigurableApplicationContext applicationContext; public static void main(String[] args) { System.out.println("正在启动。。。"); applicationContext = SpringApplication.run(WebApplication.class, args); System.out.println("启动成功"); } } 调用方式 @RestController @RequestMapping("/bean") @Api(tags = "手动获取Bean对象测试") public class BeanController { @GetMapping("test1") @ApiOperation("方式一") @ApiOperationSupport(order = 1) public IResult test1() { TestService testService = SpringUtil.getBean(TestService.class); String result = testService.test(); return IResult.success(result); } @GetMapping("test2") @ApiOperation("方式二") @ApiOperationSupport(order = 2) public IResult test2() { TestService testService = BeanUtil.getBean(TestService.class); String result = testService.test(); return IResult.success(result); } @GetMapping("test3") @ApiOperation("方式三") @ApiOperationSupport(order = 3) public IResult test3() { String result = BeanStatic.getTest(); return IResult.success(result); } @GetMapping("test4") @ApiOperation("方式四") @ApiOperationSupport(order = 4) public IResult test4() { TestService testService = WebApplication.applicationContext.getBean(TestService.class); String result = testService.test(); return IResult.success(result); } }
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