妙用CommonException

来源：互联网发布：spring web flow 知乎编辑：程序博客网时间：2024/05/29 15:55

在开发wawaji项目时，我们有个校验用户身份的逻辑。如果校验成功，返回用户信息；如果用户不存在，返回4001008；如果token失效，返回4001010；如果token不正确，返回4001011。
由于多处逻辑需要校验用户身份，所有我们希望在校验过程中，如果校验失败，直接返回失败结果，程序不再继续执行。
1.编写检验失败返回错误代码及错误提示枚举类：

public enum EnumSystemCode {    SUCC(2000, "SUCC"),    ERROR_USER_NOT_EXIST(4001008, "用户不存在"),    ERROR_TOKEN_TIMEOUT(4001010, "token失效"),    ERROR_TOKEN(4001011, "token不正确"),       COMMON(0, "错误");    @Getter    private final int code;    @Getter    private final String conent;    EnumSystemCode(int code, String content) {        this.code = code;        this.conent = content;    }    public static EnumSystemCode findByCode(int code) {        for (EnumSystemCode sCode : EnumSystemCode.values()) {            if (sCode.getCode() == code) {                return sCode;            }        }        return null;    }}

2：编写检验失败抛出的CommonException类：

public class CommonException extends RuntimeException {    private static final long serialVersionUID = 1L;    @Getter    private int code;    @Getter    private EnumSystemCode systemCode;    public CommonException(int code, String msg) {        super(msg);        this.code = code;        this.systemCode = EnumSystemCode.findByCode(code);    }    public CommonException(EnumSystemCode systemCode) {        super(systemCode.getConent());        this.code = systemCode.getCode();        this.systemCode = systemCode;    }    public CommonException(EnumSystemCode systemCode, String msg) {        super(msg);        this.code = systemCode.getCode();        this.systemCode = systemCode;    }    public CommonException(String msg) {        this(EnumSystemCode.COMMON.getCode(), msg);    }    public static CommonException getInstance(String msg, Object... args) {        for (Object object : args) {            msg = msg.replaceFirst("\\{\\}", object.toString());        }        return new CommonException(msg);    }    public static CommonException getInstance(String msg) {        return new CommonException(msg);    }}

3.业务判断时，根据不同情况提示错误信息：

if (code == EnumSystemCode.SUCC.getCode()) {    //校验成功} else if (code == EnumSystemCode.ERROR_USER_NOT_EXIST.getCode()) {    logger.info("用户不存在 , userId:{}", userId);    throw new CommonException(code, EnumSystemCode.ERROR_USER_NOT_EXIST.getConent());} else if (code == EnumSystemCode.ERROR_TOKEN_TIMEOUT.getCode()) {    logger.info("token失效 , userId:{}, token:{}", userId, token);    throw new CommonException(code, EnumSystemCode.ERROR_TOKEN_TIMEOUT.getConent());} else if (code == EnumSystemCode.ERROR_TOKEN.getCode()) {    logger.info("token不正确 , userId:{}, token:{}", userId, token);    throw new CommonException(code, EnumSystemCode.ERROR_TOKEN.getConent());}

4.抛出异常后，异常拦截器拦截：

@ControllerAdvice("com.***.web.resource")public class ResponseAdvice implements ResponseBodyAdvice<Object> {    @Override    public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> aClass) {        return true;    }    @Override    public Object beforeBodyWrite(Object o, MethodParameter methodParameter, MediaType mediaType,            Class<? extends HttpMessageConverter<?>> aClass, ServerHttpRequest serverHttpRequest,            ServerHttpResponse serverHttpResponse) {        ServletServerHttpResponse response = (ServletServerHttpResponse) serverHttpResponse;            return ApiResponse.builder().status(response.getServletResponse().getStatus()).msg("OK").data(o).build();    }    @ExceptionHandler(CommonException.class)    @ResponseBody    public ApiResponse<?> handleControllerException(HttpServletRequest request, CommonException e) {        return ApiResponse.builder().status(e.getCode()).msg(e.getMessage()).build();    }    @ExceptionHandler(Exception.class)    @ResponseBody    public ApiResponse<?> handleControllerException(HttpServletRequest request, Throwable e) {        HttpStatus status = getStatus(request);        return ApiResponse.builder().status(status.value()).msg(e.getMessage()).build();    }    private HttpStatus getStatus(HttpServletRequest request) {        Integer statusCode = (Integer) request.getAttribute("javax.servlet.error.status_code");        if (statusCode == null) {            return HttpStatus.INTERNAL_SERVER_ERROR;        }        return HttpStatus.valueOf(statusCode);    }}

通过上述配置，我们便实现了一旦校验失败，程序中止执行，立刻返回错误代码的效果。

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