exception : custom HandlerExceptionResolver

exception/src/main/java/hello/exception/WebConfig.java

@@ -3,6 +3,7 @@ package hello.exception;
 import hello.exception.filter.LogFilter;
 import hello.exception.interceptor.LogInterceptor;
 import hello.exception.resolver.MyHandlerExceptionResolver;
+import hello.exception.resolver.UserHandlerExceptionResolver;
 import org.springframework.boot.web.servlet.FilterRegistrationBean;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -28,6 +29,7 @@ public class WebConfig implements WebMvcConfigurer {
     @Override
     public void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
         resolvers.add(new MyHandlerExceptionResolver());
+        resolvers.add(new UserHandlerExceptionResolver());
     }
 
     @Bean

exception/src/main/java/hello/exception/api/ApiExceptionController.java

@@ -1,5 +1,6 @@
 package hello.exception.api;
 
+import hello.exception.exception.UserException;
 import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.extern.slf4j.Slf4j;
@@ -16,9 +17,13 @@ public class ApiExceptionController {
 
         if (id.equals("ex")) {
             throw new RuntimeException("잘못된 사용자");
-        } else if (id.equals("bad")) {
+        }
+        if (id.equals("bad")) {
             throw new IllegalArgumentException("잘못된 입력 값");
         }
+        if (id.equals("user-ex")) {
+            throw new UserException("사용자 오류");
+        }
 
         return new MemberDto(id, "hello " + id);
     }

exception/src/main/java/hello/exception/exception/UserException.java

@@ -0,0 +1,24 @@
+package hello.exception.exception;
+
+public class UserException extends RuntimeException{
+
+    public UserException() {
+        super();
+    }
+
+    public UserException(String message) {
+        super(message);
+    }
+
+    public UserException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public UserException(Throwable cause) {
+        super(cause);
+    }
+
+    protected UserException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+}

exception/src/main/java/hello/exception/resolver/UserHandlerExceptionResolver.java

@@ -0,0 +1,50 @@
+package hello.exception.resolver;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import hello.exception.exception.UserException;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.web.servlet.HandlerExceptionResolver;
+import org.springframework.web.servlet.ModelAndView;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+@Slf4j
+public class UserHandlerExceptionResolver implements HandlerExceptionResolver {
+
+    private final ObjectMapper objectMapper = new ObjectMapper();
+
+    @Override
+    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
+
+        try {
+            if (ex instanceof UserException) {
+                log.info("UserException resolver to 400");
+                String acceptHeader = request.getHeader("accept");
+
+                if ("application/json".equals(acceptHeader)) {
+                    Map<String, Object> errorResult = new HashMap<>();
+                    errorResult.put("ex", ex.getClass());
+                    errorResult.put("message", ex.getMessage());
+
+                    String result = objectMapper.writeValueAsString(errorResult);
+
+                    response.setContentType("application/json");
+                    response.setCharacterEncoding("utf-8");
+                    response.getWriter().write(result);
+                    return new ModelAndView();
+                } else {
+                    return new ModelAndView("error/500");
+                }
+
+            }
+        } catch (IOException e) {
+            log.error("resolver ex", e);
+        }
+
+        return null;
+    }
+}