SpringBoot常见YML配置、配置类和工具类代码参考¶

public record Constants() {
    public static final Integer NORMAL = 0;
    public static final Integer SERVER_ERROR = 1;
    public static final Integer SYSTEM_ERROR = 2;
    public static final Integer RESOURCE_NOT_FOUND = 3;
    public static final String SERVER_ERROR_MESSAGE = "服务器异常";
    public static final String SYSTEM_ERROR_MESSAGE = "图书管理系统异常";
    public static final String RESOURCE_NOT_FOUND_MESSAGE = "资源不存在"; 
}

@Data
@AllArgsConstructor
public class ResultWrapper<T> {
    private Integer code;
    private String errMsg;
    private T data;

    // 正常情况
    public static <T> ResultWrapper<T> normal(T data) {
        return new ResultWrapper<>(Constants.NORMAL, "", data);
    }

    // 错误情况
    public static <T> ResultWrapper<T> fail(T data) {
        return new ResultWrapper<>(Constants.SERVER_ERROR, "", data);
    }

    public static <T> ResultWrapper<T> fail(Integer code, String errMsg) {
        return new ResultWrapper<>(Constants.SERVER_ERROR, errMsg, null);
    }

    public static <T> ResultWrapper<T> fail(String errMsg, T data) {
        return new ResultWrapper<>(Constants.SERVER_ERROR, errMsg, data);
    }
}

@Slf4j
@ControllerAdvice
@ResponseBody // 防止出现持续返回视图导致的死循环情况
public class ExceptionAdvice {

    @ResponseStatus(value = HttpStatus.SERVICE_UNAVAILABLE)
    @ExceptionHandler(Exception.class)
    public ResultWrapper allExceptionHandler(Exception e) {
        // 详细日志只在后端记录
        log.error("系统异常: ", e);

        // 参数校验异常，返回具体校验信息
        if (e instanceof MethodArgumentNotValidException validException) {
            String errMsg = validException.getBindingResult().getFieldError().getDefaultMessage();
            return ResultWrapper.fail(Constants.SERVER_ERROR, errMsg);
        }

        // 其他异常返回通用提示，不暴露技术细节
        return ResultWrapper.fail(Constants.SERVER_ERROR, Constants.SERVER_ERROR_MESSAGE);
    }

    @ResponseStatus(value = HttpStatus.SERVICE_UNAVAILABLE)
    @ExceptionHandler(MusicException.class)
    public ResultWrapper musicExceptionHandler(MusicException e) {
        // 业务异常记录日志
        log.warn("业务异常: {}", e.getMessage());

        // 业务异常可以返回具体提示（因为是我们自己定义的友好提示）
        return ResultWrapper.fail(Constants.SYSTEM_ERROR, e.getMessage());
    }

    @ResponseStatus(value = HttpStatus.NOT_FOUND)
    @ExceptionHandler(NoResourceFoundException.class)
    public ResultWrapper noResourceFoundException(NoResourceFoundException e) {
        log.warn("资源不存在: {}", e.getResourcePath());
        return ResultWrapper.fail(Constants.RESOURCE_NOT_FOUND, Constants.RESOURCE_NOT_FOUND_MESSAGE);
    }

    @ResponseStatus(value = HttpStatus.SERVICE_UNAVAILABLE)
    @ExceptionHandler(IllegalStateException.class)
    public ResultWrapper illegalStateExceptionHandler(IllegalStateException e) {
        log.warn("状态异常: {}", e.getMessage());
        // 状态异常通常是业务逻辑问题，返回具体提示
        return ResultWrapper.fail(Constants.SYSTEM_ERROR, e.getMessage());
    }

    @ResponseStatus(value = HttpStatus.SERVICE_UNAVAILABLE)
    @ExceptionHandler(RuntimeException.class)
    public ResultWrapper runtimeExceptionHandler(RuntimeException e) {
        log.error("运行时异常: ", e);

        // 检查是否是初始化相关的异常，返回友好提示
        String message = e.getMessage();
        if (message != null && message.contains("连接")) {
            return ResultWrapper.fail(Constants.SYSTEM_ERROR, "连接失败，请检查网络或重试");
        }
        if (message != null && message.contains("Cookie")) {
            return ResultWrapper.fail(Constants.SYSTEM_ERROR, "Cookie 无效或已过期，请重新输入");
        }

        // 其他运行时异常返回通用提示
        return ResultWrapper.fail(Constants.SERVER_ERROR, Constants.SERVER_ERROR_MESSAGE);
    }
}

@Configuration
public class WebConfig implements WebMvcConfigurer {
    @Value("${app.cors.allowed-origins}") // 参考通用配置文件
    private String allowedOrigins;

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        String[] origins = allowedOrigins.split(",");
        registry.addMapping("/**")
                .allowedOrigins(origins)
                .allowedMethods("GET", "POST", "PUT", "DELETE", "OPTIONS")
                .allowedHeaders("*")
                .allowCredentials(true)
                .maxAge(3600);
    }
}

@Data
@EqualsAndHashCode(callSuper = true)
public class BookManagerException extends RuntimeException{
    public Integer code;
    public String message;

    public BookManagerException() {
    }

    public BookManagerException(Integer code) {
        this.code = code;
    }

    public BookManagerException(String message) {
        this.message = message;
    }

    public BookManagerException(Integer code, String message) {
        this.code = code;
        this.message = message;
    }
}

@Slf4j
public class JsonUtil {
    // 对象转Json字符串
    public static String toJson(Object o) {
        try {
            return o == null ? null : JSON.toJSONString(o);
        } catch (Exception e) {
            log.error("对象转JSON字符串出现异常，e：{}", e.getMessage());
            return null;
        }
    }

    // Json字符串转对象
    public static <T> T toObject(String json, Class<T> cls) {
        try {
            if (cls == null || !StringUtils.hasLength(json)) {
                return null;
            }
            return JSON.parseObject(json, cls);
        } catch (Exception e) {
            log.error("JSON字符串转对象出现异常，e：{}", e.getMessage());
            return null;
        }
    }
}

@Component
public class MailUtil {

    private final JavaMailSender javaMailSender;
    private final MailProperties mailProperties;

    public MailUtil(JavaMailSender javaMailSender, MailProperties mailProperties) {
        this.javaMailSender = javaMailSender;
        this.mailProperties = mailProperties;
    }

    public void sendMail(String to, String subject, String html) throws Exception {
        MimeMessage mimeMessage = javaMailSender.createMimeMessage();
        MimeMessageHelper mimeMessageHelper = new MimeMessageHelper(mimeMessage, false);
        mimeMessageHelper.setFrom(mailProperties.getUsername(), mailProperties.getProperties().get("personal"));
        mimeMessageHelper.setTo(to);
        mimeMessageHelper.setSubject(subject);
        mimeMessageHelper.setText(html, true);

        javaMailSender.send(mimeMessage);
    }
}