一、@RestControllerAdvice是什么?
@RestContrllerAdvice是一种组合注解，由@ControllerAdvice，@ResponseBody组成
@ControllerAdvice继承了@***ponent，反过来，可以理解为@RestContrllerAdvice本质上就是@***ponent
1.1 @***ponent是什么？
本质上是一个类，泛指各种组件，就是说当我们的类不属于各种归类的时候(不属于@Controller，@Service等的时候)，我们就可以使用@***ponent
作用就是实现bean注入，利用这个注解可以取代spring的xml配置文件
1.2 @***ponent案例
1.2.1 准备的jar
java"> <dependency>
<groupId>***.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.75</version>
</dependency>
1.2.2 controller
@RestController
public class TestController {
@Autowired
private TestService testService;
@GetMapping("/test3")
public String test3() {
return testService.test();
}
}1.2.3 接口
public interface TestService {
String test();
}1.2.4组件
@***ponent
public class TestServiceImpl implements TestService {
@Autowired
private ObjectMapper objectMapper;
@Override
public String test() {
String b = null;
try {
b = objectMapper.writeValueAsString("a");
System.out.println(b);
} catch (Exception e) {
}
return b;
}
}二、@RestControllerAdvice有什么作用？
自定义客户端返回格式
捕获客户端返回异常
三、@RestControllerAdvice案例和使用场景
捕获客户端返回异常案例(自定义返回异常)
3.1 未自定义捕获异常之前
3.2 自定义捕获异常以后
3.3代码实现自定义捕获异常
3.3.1 自定义异常枚举
public interface BaseCodeMsg {
String getCode();
String getMsg();
}public enum PlatformExceptionMsgEnum implements BaseCodeMsg {
/**
* base平台返回的异常信息
*/
SELECT_NULL("000000001", "查询数据为空"),
INVOKE_IS_REJECT("00000002", "请求被拒绝"),
ILLEGAL_ARGUMENT_FORMAT("000000003", "非法参数格式"),
ILLEGAL_ARGUMENT("000000004","数据非法"),
SYSTEM_EXCEPTION("000000005", "系统异常");
/**
* 错误码
*/
private final String code;
/**
* 错误信息
*/
private final String msg;
PlatformExceptionMsgEnum(String code, String msg) {
this.code = code;
this.msg = msg;
}
@Override
public String getCode() {
return code;
}
@Override
public String getMsg() {
return msg;
}
}3.3.2 自定义平台异常
public abstract class AbstractApiException extends RuntimeException{
public AbstractApiException() {
}
public abstract String getCode();
public abstract String getMsg();
}public class PlatformException extends AbstractApiException {
private String code;
private String msg;
public PlatformException(BaseCodeMsg baseCodeMsg) {
code = baseCodeMsg.getCode();
msg = baseCodeMsg.getMsg();
}
public static void throwException(BaseCodeMsg baseCodeMsg) {
throw new PlatformException(baseCodeMsg.getCode(), baseCodeMsg.getMsg());
}
public static void throwException(BaseCodeMsg baseCodeMsg, String msg) {
throw new PlatformException(baseCodeMsg.getCode(), StringUtils.isEmpty(baseCodeMsg.getMsg()) ? msg : baseCodeMsg.getMsg());
}
public static void throwException(String code, String msg) {
throw new PlatformException(code, msg);
}
public static void throwException(String msg) {
throw new PlatformException(PlatformExceptionMsgEnum.SYSTEM_EXCEPTION.getCode(), msg);
}
public PlatformException(String code, String msg) {
this.code = code;
this.msg = msg;
}
@Override
public String getCode() {
return code;
}
@Override
public String getMsg() {
return msg;
}
}3.3.3 自定义返回类
@Data
public class BaseResult<T> implements Serializable {
private static final long serialVersionUID = 1L;
private String code;
private String msg;
private String traceId;
private T data;
public boolean isSu***ess() {
return PlatformExceptionMsgEnum.SU***ESS.getCode().equals(this.code);
}
public static BaseResult ok() {
return restBaseResult((Object)null, PlatformExceptionMsgEnum.SU***ESS);
}
public static <T> BaseResult<T> ok(T data) {
return restBaseResult(data, PlatformExceptionMsgEnum.SU***ESS);
}
public static BaseResult fail() {
return restBaseResult((Object)null, PlatformExceptionMsgEnum.SYSTEM_ERROR);
}
public static BaseResult fail(BaseCodeMsg baseCodeMsg) {
return restBaseResult((Object)null, baseCodeMsg);
}
public static BaseResult fail(String code, String msg) {
return restBaseResult((Object)null, code, msg);
}
private static <T> BaseResult<T> restBaseResult(T data, BaseCodeMsg baseCodeMsg) {
return restBaseResult(data, baseCodeMsg.getCode(), baseCodeMsg.getMsg());
}
private static <T> BaseResult<T> restBaseResult(T data, String code, String msg) {
BaseResult<T> apiBaseResult = new BaseResult();
apiBaseResult.setCode(code);
apiBaseResult.setData(data);
apiBaseResult.setMsg(msg);
apiBaseResult.setTraceId(MDC.get("traceId"));
return apiBaseResult;
}
public BaseResult() {
}
}3.3.4 controller层
@RestController
public class TestController {
@GetMapping("/test")
public void test() {
PlatformException.throwException(PlatformExceptionMsgEnum.SYSTEM_EXCEPTION);
}
}3.3.5 @RestControllerAdvice
@RestControllerAdvice
@Configuration
public class GlobalExceptionHandler {
private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);
private MessageSource messageSource;
/**
* 捕获全局异常类
*
* @param e
* @return
*/
@ExceptionHandler({MethodArgumentNotValidException.class})
public BaseResult handle(MethodArgumentNotValidException e) {
if (e.getBindingResult().hasErrors()) {
String msg = ((ObjectError) e.getBindingResult().getAllErrors().get(0)).getDefaultMessage();
return BaseResult.fail(PlatformExceptionMsgEnum.ILLEGAL_ARGUMENT.getCode(), this.getI18nMsg(msg));
} else {
log.info(e.getMessage(), e);
return BaseResult.fail(PlatformExceptionMsgEnum.ILLEGAL_ARGUMENT.getCode(), this.getI18nMsg(PlatformExceptionMsgEnum.ILLEGAL_ARGUMENT.getMsg()));
}
}
/**
* 捕获API调用接口的异常类
*
* @param e
* @return
*/
@ExceptionHandler(AbstractApiException.class)
public BaseResult abstractApiException(AbstractApiException e) {
return BaseResult.fail(e.getCode(), e.getMsg());
}
/**
* 前端传入的参数和后端传入的参数接收不匹配
*
* @param e
* @return
*/
@ExceptionHandler({HttpMessageNotReadableException.class})
public BaseResult handle(HttpMessageNotReadableException e) {
log.warn(e.getMessage(), e);
return BaseResult.fail(PlatformExceptionMsgEnum.ILLEGAL_ARGUMENT_FORMAT.getCode(), this.getI18nMsg(PlatformExceptionMsgEnum.ILLEGAL_ARGUMENT_FORMAT.getMsg()));
}
/**
* 子类异常(相当于子类不能抛出比父类更广泛异常)
*
* @param e
* @return
*/
@ExceptionHandler({UndeclaredThrowableException.class})
public BaseResult handle(UndeclaredThrowableException e) {
log.warn(e.getMessage(), e);
return BaseResult.fail(PlatformExceptionMsgEnum.INVOKE_IS_REJECT.getCode(), this.getI18nMsg(PlatformExceptionMsgEnum.INVOKE_IS_REJECT.getMsg()));
}
/**
* 异常捕获
*
* @param e 捕获的异常，封装返回的对象
* @return
*/
@ExceptionHandler(Exception.class)
public BaseResult handleException(Exception e) {
log.warn(e.getMessage(), e);
StringJoiner joiner = new StringJoiner(":");
joiner.add(this.getI18nMsg(PlatformExceptionMsgEnum.INVOKE_IS_REJECT.getMsg())).add(e.getMessage());
return BaseResult.fail(PlatformExceptionMsgEnum.SYSTEM_EXCEPTION.getCode(), joiner.toString());
}
private String getI18nMsg(String msg) {
try {
return this.messageSource.getMessage(msg, (Object[]) null, LocaleContextHolder.getLocale());
} catch (NoSuchMessageException var3) {
return msg;
}
}
public GlobalExceptionHandler(MessageSource messageSource) {
this.messageSource = messageSource;
}
}3.4 代码实现自定义返回结果
没有自定义返回结果之前
自定义返回结果以后
3.4.1 controller
@RestController
public class TestController {
@GetMapping("/test2")
public String test2() {
return "test2";
}
}3.4.2 返回结果来
BaseResult返回结果类在上面，对应需要导入json的jar也在上面
3.4.3 @RestControllerAdvice
@RestControllerAdvice(
annotations = {RestController.class}
)
@Configuration
public class BaseResultResponseAdvice implements ResponseBodyAdvice<Object> {
@Autowired
private ObjectMapper objectMapper;
/**
* @param methodParameter 利用这个参数判断注解信息
* @param aClass
* @return
*/
@Override
public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> aClass) {
return true;
}
/**
* @param body 原controller需要返回的内容
* @param methodParameter 利用这个参数判断注解信息
* @param mediaType
* @param aClass
* @param serverHttpRequest
* @param serverHttpResponse
* @return
*/
@Override
public Object beforeBodyWrite(Object body, MethodParameter methodParameter, MediaType mediaType, Class<? extends HttpMessageConverter<?>> aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {
try {
if (methodParameter.getParameterType() == ResponseEntity.class) {
return body;
} else if (methodParameter.getParameterType() == BaseResult.class) {
return body;
} else if (methodParameter.getParameterType() == String.class) {
serverHttpResponse.getHeaders().setContentType(MediaType.APPLICATION_JSON);
return this.objectMapper.writeValueAsString(BaseResult.ok(body));
} else {
return BaseResult.ok(body);
}
} catch (Throwable t) {
return BaseResult.fail();
}
}
}四、拓展
@RestControllerAdvice的使用还可以指定对应的注解、包，类。比如你需要返回自定义结果格式，可以指定@RestController层使用，如果你要指定类和包也可以
4.1 指定注解
@RestControllerAdvice(
annotations = {RestController.class}
)4.2 指定类
@RestControllerAdvice(
basePackageClasses = TestController.class
)4.3 指定包
@RestControllerAdvice(
basePackages = "***.***mon.base.controller"
)
