Springboot 通过类路径从ioc容器中获得Bean

2022-04-13  本文已影响0人  往后余生9375

SpringUtils

public class SpringUtils {

    private static boolean supportSpringBean = false;

    private static ApplicationContext context;

    public static void inject(ApplicationContext ctx) {
        context = ctx;
        supportSpringBean = true;
    }

    public static boolean supportSpringBean() {
        return supportSpringBean;
    }

    public static <T> T getBean(Class<T> clz) {
        return context.getBean(clz);
    }

    @SuppressWarnings("unchecked")
    public static <T> T getBean(String className) throws Exception {

        // 1. ClassLoader 存在,则直接使用 clz 加载
        ClassLoader classLoader = context.getClassLoader();
        if (classLoader != null) {
            return (T) context.getBean(classLoader.loadClass(className));
        }
        // 2. ClassLoader 不存在(系统类加载器不可见),尝试用类名称小写加载
        String[] split = className.split("\\.");
        String beanName = split[split.length - 1];
        // 小写转大写
        char[] cs = beanName.toCharArray();
        cs[0] += 32;
        String beanName0 = String.valueOf(cs);
        return (T) context.getBean(beanName0);
    }
}

Application

@SpringBootApplication
public class DllUtilsApplication implements ApplicationContextAware {

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        SpringUtils.inject(applicationContext);
    }

    public static void main(String[] args) {
        SpringApplication.run(DllUtilsApplication.class, args);
    }

}

使用

// Test使用@Component注解
Test test = SpringUtils.getBean("com.example.dllutils.Test");
test.print();
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