init commit

src/main/java/me/hatter/sample/Application.java

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+package me.hatter.sample;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.ComponentScan;
+
+@ComponentScan(basePackages = "me.hatter.sample")
+@SpringBootApplication
+public class Application {
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+
+//    @Bean
+//    public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
+//        return args -> {
+//
+//            System.out.println("Let's inspect the beans provided by Spring Boot:");
+//
+//            String[] beanNames = ctx.getBeanDefinitionNames();
+//            Arrays.sort(beanNames);
+//            for (String beanName : beanNames) {
+//                System.out.println(beanName);
+//            }
+//
+//        };
+//    }
+}

src/main/java/me/hatter/sample/common/WebConfig.java

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+package me.hatter.sample.common;
+
+import me.hatter.sample.common.resolver.SystemTimeArgumentResolver;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.method.support.HandlerMethodArgumentResolver;
+import org.springframework.web.servlet.config.annotation.*;
+
+import java.util.List;
+
+@Configuration
+public class WebConfig extends WebMvcConfigurerAdapter {
+
+    @Autowired
+    SystemTimeArgumentResolver systemTimeArgumentResolver;
+
+    @Override
+    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
+        argumentResolvers.add(systemTimeArgumentResolver);
+    }
+}

src/main/java/me/hatter/sample/common/annotation/SystemTime.java

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+package me.hatter.sample.common.annotation;
+
+import java.lang.annotation.*;
+
+@Target(ElementType.PARAMETER)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+public @interface SystemTime {
+}

src/main/java/me/hatter/sample/common/resolver/SystemTimeArgumentResolver.java

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+package me.hatter.sample.common.resolver;
+
+import me.hatter.sample.common.annotation.SystemTime;
+import org.springframework.core.MethodParameter;
+import org.springframework.stereotype.Component;
+import org.springframework.web.bind.support.WebDataBinderFactory;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.method.support.HandlerMethodArgumentResolver;
+import org.springframework.web.method.support.ModelAndViewContainer;
+
+import java.util.Date;
+
+@Component
+public class SystemTimeArgumentResolver implements HandlerMethodArgumentResolver {
+    @Override
+    public boolean supportsParameter(MethodParameter parameter) {
+        return parameter.hasParameterAnnotation(SystemTime.class);
+    }
+
+    @Override
+    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
+        return new Date();
+    }
+}

src/main/java/me/hatter/sample/web/controller/SampleController.java

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+package me.hatter.sample.web.controller;
+
+import me.hatter.sample.common.annotation.SystemTime;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.Date;
+
+@RestController
+public class SampleController {
+
+    @GetMapping("/")
+    public String home(
+            @SystemTime Date time) {
+        return "Hello, World: " + time;
+    }
+}