Java 異常分為兩大派系，體現了設計者對「可控性」的不同預期：
| 維度 | 受檢異常 (Checked Exception) | 非受檢異常 (Unchecked Exception) |
|---|---|---|
| 繼承體系 | Exception (非 RuntimeException) | RuntimeException、Error |
| 編譯器強制 | ✅ 必須 catch 或 throws | ❌ 無強制要求 |
| 典型代表 | IOException、SQLException、TimeoutException | NullPointerException、IllegalArgumentException、ArithmeticException |
| 業務含義 | 外部依賴失敗、資源不可用、可預期且可恢復 | 編程邏輯錯誤、不可預期、通常不可恢復 |
| 處理策略 | 捕獲轉換、重試、降級、用戶友好提示 | 修復代碼、添加防禦檢查、全局捕獲記錄 |
// 根異常：攜帶錯誤碼、國際化鍵、動態參數
public class BizException extends RuntimeException {
private final String code;
private final Object[] args;
public BizException(String code, Object... args) {
super(code); // message 存 code，便於日誌檢索
this.code = code;
this.args = args;
}
public String getCode() { return code; }
public Object[] getArgs() { return args; }
}
// 業務細分異常 (可選，便於針對性捕獲)
public class ResourceNotFoundException extends BizException {
public ResourceNotFoundException(String resourceType, String id) {
super("error.resource.notfound", resourceType, id);
}
}
public class BusinessRuleViolationException extends BizException {
public BusinessRuleViolationException(String rule, Object... args) {
super("error.rule.violation", args);
}
}
// 系統級異常 (包裝第三方異常)
public class SystemException extends RuntimeException {
public SystemException(String message, Throwable cause) {
super(message, cause);
}
}<error-page>
<error-code>404</error-code>
<location>/error/404.html</location>
</error-page>
<error-page>
<error-code>500</error-code>
<location>/error/500.html</location>
</error-page>
<error-page>
<exception-type>java.lang.Throwable</exception-type>
<location>/error/uncaught.html</location>
</error-page>
<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="exceptionMappings">
<props>
<prop key="com.xxx.BizException">error/biz</prop>
<prop key="org.springframework.dao.DataAccessException">error/db</prop>
<prop key="java.lang.Exception">error/500</prop>
</props>
</property>
<property name="defaultErrorView" value="error/500"/>
<property name="warnLogCategory" value="WARN"/>
</bean>
@Component
public class GlobalExceptionResolver implements HandlerExceptionResolver {
private static final Logger log = LoggerFactory.getLogger(GlobalExceptionResolver.class);
private final ObjectMapper objectMapper = new ObjectMapper();
@Override
public ModelAndView resolveException(HttpServletRequest request,
HttpServletResponse response, Object handler, Exception ex) {
// 1. 識別 AJAX/REST 請求
boolean isAjax = "XMLHttpRequest".equals(request.getHeader("X-Requested-With"))
|| request.getRequestURI().startsWith("/api/");
// 2. 構建統一響應
ApiResponse resp = buildResponse(ex);
if (isAjax) {
// JSON 響應
writeJsonResponse(response, resp);
return null; // 已寫入響應，不需視圖解析
} else {
// 頁面跳轉
ModelAndView mav = new ModelAndView("error/page");
mav.addObject("error", resp);
return mav;
}
}
private ApiResponse buildResponse(Exception ex) {
if (ex instanceof BizException) {
BizException be = (BizException) ex;
return ApiResponse.fail(be.getCode(), be.getArgs());
} else if (ex instanceof ConstraintViolationException) {
return ApiResponse.fail("error.validation", ex.getMessage());
} else if (ex instanceof DataAccessException) {
log.error("數據庫訪問異常", ex);
return ApiResponse.fail("error.database");
} else {
log.error("系統未知異常", ex);
return ApiResponse.fail("error.system");
}
}
private void writeJsonResponse(HttpServletResponse response, ApiResponse resp) {
response.setCharacterEncoding("UTF-8");
response.setContentType("application/json;charset=UTF-8");
try {
objectMapper.writeValue(response.getWriter(), resp);
} catch (IOException e) {
log.error("異常響應序列化失敗", e);
}
}
}
// 統一響應結構
public class ApiResponse {
private boolean success;
private String code;
private String message;
private Object data;
private long timestamp = System.currentTimeMillis();
public static ApiResponse ok(Object data) { ... }
public static ApiResponse fail(String code, Object... args) { ... }
// getter/setter
}
