@ControllerAdvice
Spring原始碼中有關@ControllerAdvice的註解如下：
Specialization of {@link Component @Component} for classes that declare {@link ExceptionHandler @ExceptionHandler}, {@link InitBinder @InitBinder}, or {@link ModelAttribute @ModelAttribute} methods to be shared across multiple {@code @Controller} classes.
理解：
@ControllerAdvice是一個特殊的@Component，用於標識一個類，這個類中被以下三種註解標識的方法：@ExceptionHandler，@InitBinder，@ModelAttribute，將作用於所有的@Controller類的介面上。
那麼，這個三個註解分別是什麼意思，起到什麼作用呢？
@InitBinder
Annotation that identifies methods which initialize the {@link org.springframework.web.bind.WebDataBinder} which will be used for populating command and form object arguments of annotated handler methods. Such init-binder methods support all arguments that {@link RequestMapping} supports, except for command/form objects and corresponding validation result objects. Init-binder methods must not have a return value; they are usually declared as {@code void}.
作用：註冊屬性編輯器，對HTTP請求引數進行處理，再繫結到對應的介面，比如格式化的時間轉換等。應用於單個@Controller類的方法上時，僅對該類裡的介面有效。與@ControllerAdvice組合使用可全域性生效。
示例：
@ControllerAdvice
public class ActionAdvice {
@InitBinder
public void handleException(WebDataBinder binder) {
binder.addCustomFormatter(new DateFormatter("yyyy-MM-dd HH:mm:ss"));
}
}
複製程式碼@ExceptionHandler
作用：統一異常處理，也可以指定要處理的異常型別
示例：
@ControllerAdvice
public class ActionAdvice {
@ExceptionHandler(Exception.class)
@ResponseBody
@ResponseStatus(HttpStatus.OK)
public Map handleException(Exception ex) {
Map<String, Object> map = new HashMap<>();
map.put("code", 400);
map.put("msg", ex.toString());
return map;
}
}
複製程式碼@ModelAttribute
作用：繫結資料
示例：
@ControllerAdvice
public class ActionAdvice {
@ModelAttribute
public void handleException(Model model) {
model.addAttribute("user", "zfh");
}
}
複製程式碼在介面中獲取前面繫結的引數：
@RestController
public class BasicController {
@GetMapping(value = "index")
public Map index(@ModelAttribute("user") String user) {
//...
}
}
複製程式碼完整示例程式碼：
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.format.datetime.DateFormatter;
import org.springframework.http.HttpStatus;
import org.springframework.ui.Model;
import org.springframework.validation.Validator;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.*;
import java.util.HashMap;
import java.util.Map;
/**
* 統一異常處理
* @author zfh
* @version 1.0
* @since 2019/1/4 15:23
*/
@ControllerAdvice
public class ControllerExceptionHandler {
private Logger logger = LoggerFactory.getLogger(ControllerExceptionHandler.class);
@InitBinder
public void initMyBinder(WebDataBinder binder) {
// 新增對日期的統一處理
//binder.addCustomFormatter(new DateFormatter("yyyy-MM-dd"));
binder.addCustomFormatter(new DateFormatter("yyyy-MM-dd HH:mm:ss"));
// 新增表單驗證
//binder.addValidators();
}
@ModelAttribute
public void addMyAttribute(Model model) {
model.addAttribute("user", "zfh"); // 在@RequestMapping的介面中使用@ModelAttribute("name") Object name獲取
}
@ExceptionHandler(value = Exception.class)
@ResponseStatus(HttpStatus.OK)
@ResponseBody // 如果使用了@RestControllerAdvice，這裡就不需要@ResponseBody了
public Map handler(Exception ex) {
logger.error("統一異常處理", ex);
Map<String, Object> map = new HashMap<>();
map.put("code", 400);
map.put("msg", ex);
return map;
}
}
複製程式碼測試介面：
@RestController
public class TestAction {
@GetMapping(value = "testAdvice")
public JsonResult testAdvice(@ModelAttribute("user") String user, Date date) throws Exception {
System.out.println("user: " + user);
System.out.println("date: " + date);
throw new Exception("直接丟擲異常");
}
}
複製程式碼高階應用--格式化時間轉Date
使用@ControllerAdvice + @InitBinder，可將http請求引數中的時間自動轉換成Date型別。
@InitBinder
public void initBinder(WebDataBinder binder) {
GenericConversionService genericConversionService = (GenericConversionService) binder.getConversionService();
if (genericConversionService != null) {
genericConversionService.addConverter(new DateConverter());
}
}
複製程式碼自定義的時間型別轉換器：
import org.springframework.core.convert.converter.Converter;
import org.springframework.util.StringUtils;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* 日期轉換類
* 將標準日期、標準日期時間、時間戳轉換成Date型別
*/
public class DateConverter implements Converter<String, Date> {
private static final String dateFormat = "yyyy-MM-dd HH:mm:ss";
private static final String shortDateFormat = "yyyy-MM-dd";
private static final String timeStampFormat = "^\\d+$";
@Override
public Date convert(String value) {
if(StringUtils.isEmpty(value)) {
return null;
}
value = value.trim();
try {
if (value.contains("-")) {
SimpleDateFormat formatter;
if (value.contains(":")) {
formatter = new SimpleDateFormat(dateFormat);
} else {
formatter = new SimpleDateFormat(shortDateFormat);
}
return formatter.parse(value);
} else if (value.matches(timeStampFormat)) {
Long lDate = new Long(value);
return new Date(lDate);
}
} catch (Exception e) {
throw new RuntimeException(String.format("parser %s to Date fail", value));
}
throw new RuntimeException(String.format("parser %s to Date fail", value));
}
}
複製程式碼擴充套件：
@RestControllerAdvice = @ControllerAdvice + @ResponseBody
參考：