> 一切的起源来自与我使用 `knife4j` 时，一直被它这里默认有个 basic-error-controller 所困扰，一开始我不以为然，而后来我使用 openapi 自动生成前端接口时，因为文档中这个 basic-error-controller 导致代码看起来很奇怪。所以我经过一番搜索，找到了合适的解决方案



![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/10725de52b08978d2bd214f64b4fb97e.png)

因为 `knife4j` 无法指定扫描的 controller 目录，以至于我一直无法处理掉这个 controller。
经过搜索发现，它是来自于 `springboot` 包下的一个 controller

![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/1ac964026e85ea6010b2ed2bc069088b.png)

罪魁祸首就是他们

![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/8162f0b47a5146c0e18957f6f78027db.png)


spring boot 默认错误处理是这样的
1. 浏览器，默认返回一个错误页面
![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/0a94b8f88d4f710129a3e5c2363e6ad7.png)
![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/b13de53e971fbc71b79a620f8ee60819.png)

2. 如果是通过接口请求，它是这样的
![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/bb73eed690a34c17a0dbcd1167ccb061.png)

它的原理大概是这样的
```java
@Controller
@RequestMapping("${server.error.path:${error.path:/error}}")
public class BasicErrorController extends AbstractErrorController {
    
    @RequestMapping(produces = "text/html")//产生html类型的数据；浏览器发送的请求来到这个方法处理
	public ModelAndView errorHtml(HttpServletRequest request,
			HttpServletResponse response) {
		HttpStatus status = getStatus(request);
		Map<String, Object> model = Collections.unmodifiableMap(getErrorAttributes(
				request, isIncludeStackTrace(request, MediaType.TEXT_HTML)));
		response.setStatus(status.value());
        
        //去哪个页面作为错误页面；包含页面地址和页面内容
		ModelAndView modelAndView = resolveErrorView(request, response, status, model);
		return (modelAndView == null ? new ModelAndView("error", model) : modelAndView);
	}

	@RequestMapping
	@ResponseBody    //产生json数据，其他客户端来到这个方法处理；
	public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
		Map<String, Object> body = getErrorAttributes(request,
				isIncludeStackTrace(request, MediaType.ALL));
		HttpStatus status = getStatus(request);
		return new ResponseEntity<Map<String, Object>>(body, status);
	}
```

我们可以通过继承 `BasicErrorController` 重写 `errorHtml` 和 `error` 方法修改返回的数据或者页面

又由于继承的 controller 写到了我们自己的包下，于是我们可以轻易控制在 `knife4j` 中的显示

![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/a1dfbce94a81ba38c5566854f4ad0c87.png)

例如像我这样，使用 `thymeleaf` 生成页面，让错误页面看起来也很不错
```java
/**
 * 覆盖SpringBoot 默认错误处理器
 */
@Controller
@ApiIgnore
public class ErrorController extends BasicErrorController {
  public ErrorController(ErrorAttributes errorAttributes,
                         ServerProperties serverProperties,
                         List<ErrorViewResolver> errorViewResolvers) {
    super(errorAttributes, serverProperties.getError(), errorViewResolvers);
  }

  /**
   * 返回的html/text页面
   *
   * @param request
   * @param response
   * @return
   */
  @Override
  public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) {
    HttpStatus status = getStatus(request);
    // 获取 Spring Boot 默认提供的错误信息，然后添加一个自定义的错误信息
    Map<String, Object> model = getErrorAttributes(request,
        getErrorAttributeOptions(request, MediaType.TEXT_HTML));
    return new ModelAndView("errorPage", model, status);
  }

  /**
   * 返回的json数据
   *
   * @param request
   * @return
   */
  @Override
  public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
    HttpStatus status = getStatus(request);
    // 获取 Spring Boot 默认提供的错误信息，然后添加一个自定义的错误信息
    Map<String, Object> body = getErrorAttributes(request,
        getErrorAttributeOptions(request, MediaType.TEXT_HTML));
    return new ResponseEntity<>(R.error(ErrorCode.SYSTEM_ERROR).toMap(), status);
  }
}
```

在 `templates/errorPage.html` 中写入页面内容

```html
<!doctype html>
<html lang="zh">
<head>
  <meta charset="UTF-8">
  <meta name="viewport"
        content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>系统错误</title>
  <style>
      样式...
  </style>
</head>
<body>
<div style="display: flex;flex-direction: column;justify-content: center;align-items: center;height: 100vh;">
  <svg width="254" height="294">
  可以放个图片
  </svg>
  <table>
  还可以将错误信息用表格的形式列出
    <tr>
      <td>timestamp</td>
      <td th:text="${timestamp}"></td>
    </tr>
    <tr>
      <td>status</td>
      <td th:text="${status}"></td>
    </tr>
    <tr>
      <td>error</td>
      <td th:text="${error}"></td>
    </tr>
    <tr>
      <td>message</td>
      <td th:text="${message}"></td>
    </tr>
    <tr>
      <td>path</td>
      <td th:text="${path}"></td>
    </tr>
  </table>
</div>
</body>
</html>

```

错误页面像这样
![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/cd9d2435cca068ed3a666b89e38ce82c.png)

Spring Boot自定义Controller错误处理页

> 后端返回的字符串总是不规范？总要前端自己去格式化？把这篇文章发给TA，让TA学会使用全局时间格式化。



(像这种情况，其实困扰了我挺久的，添加很多配置，什么拦截器什么的，都不是很管用)
![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/949db42aa7ffdb05e1e75cc158f86181.png)

直到我使用jackson的jsonFormat，就能对时间进行格式化。
(不过这种我配置是不生效的，大家可根据自己情况来)
![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/e9b8f0365ffce0db0d06f34397383d34.png)

**全局格式化**
```java
/**
 * 时间格式化配置
 */
@JsonComponent
public class DateFormatConfig {
  @Value("${spring.jackson.date-format:yyyy-MM-dd HH:mm:ss}")
  private String pattern;
  @Resource
  @Lazy
  private LocalDateTimeSerializer localDateTimeDeserializer;

  /**
   * date 类型全局时间格式化
   */
  @Bean
  public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilder() {

    return builder -> {
      TimeZone tz = TimeZone.getTimeZone("UTC");
      DateFormat df = new SimpleDateFormat(pattern);
      df.setTimeZone(tz);
      builder.failOnEmptyBeans(false)
          .failOnUnknownProperties(false)
          .featuresToDisable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
          .dateFormat(df);
    };
  }

  /**
   * LocalDate 类型全局时间格式化
   */
  @Bean
  public LocalDateTimeSerializer localDateTimeDeserializer() {
    return new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(pattern));
  }

  @Bean
  public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
    return builder -> builder.serializerByType(LocalDateTime.class, localDateTimeDeserializer);
  }
}
```

在实体类上，如果需要指定另外的格式方式，也可使用`@JsonFormat`注解
```java
public class UserVO implements Serializable {
  private String username;
  private String nickname;
  private String role;
  private String phone;
  private String email;
  // 已全局配置时间格式化，亦可使用 @JsonFormat(locale = "zh", timezone = "GMT+8", pattern = "yyyy-MM-dd")的方式
  private LocalDateTime createTime;
}
```

后端时间格式化问题？一个配置解决它

> 这个主要是我在开发时对于 这个responseCode有点疑惑，毕竟这里面的状态码可能大部分HTTP状态码都实现了，于是谷歌到这个问题，实际上和我有相同疑惑的人不在少数，看看他们是怎么回答的。https://www.v2ex.com/t/676678?p=1



![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/15f260a0050f22255f6e1d11070f17f4.png)

实际上HTTP状态码有很多，简单看看MDN上的定义https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Status

列出来大概是这么多
```ts
declare enum HttpStatusCode {
  Continue = 100,
  SwitchingProtocols = 101,
  Processing = 102,
  EarlyHints = 103,
  Ok = 200,
  Created = 201,
  Accepted = 202,
  NonAuthoritativeInformation = 203,
  NoContent = 204,
  ResetContent = 205,
  PartialContent = 206,
  MultiStatus = 207,
  AlreadyReported = 208,
  ImUsed = 226,
  MultipleChoices = 300,
  MovedPermanently = 301,
  Found = 302,
  SeeOther = 303,
  NotModified = 304,
  UseProxy = 305,
  Unused = 306,
  TemporaryRedirect = 307,
  PermanentRedirect = 308,
  BadRequest = 400,
  Unauthorized = 401,
  PaymentRequired = 402,
  Forbidden = 403,
  NotFound = 404,
  MethodNotAllowed = 405,
  NotAcceptable = 406,
  ProxyAuthenticationRequired = 407,
  RequestTimeout = 408,
  Conflict = 409,
  Gone = 410,
  LengthRequired = 411,
  PreconditionFailed = 412,
  PayloadTooLarge = 413,
  UriTooLong = 414,
  UnsupportedMediaType = 415,
  RangeNotSatisfiable = 416,
  ExpectationFailed = 417,
  ImATeapot = 418,
  MisdirectedRequest = 421,
  UnprocessableEntity = 422,
  Locked = 423,
  FailedDependency = 424,
  TooEarly = 425,
  UpgradeRequired = 426,
  PreconditionRequired = 428,
  TooManyRequests = 429,
  RequestHeaderFieldsTooLarge = 431,
  UnavailableForLegalReasons = 451,
  InternalServerError = 500,
  NotImplemented = 501,
  BadGateway = 502,
  ServiceUnavailable = 503,
  GatewayTimeout = 504,
  HttpVersionNotSupported = 505,
  VariantAlsoNegotiates = 506,
  InsufficientStorage = 507,
  LoopDetected = 508,
  NotExtended = 510,
  NetworkAuthenticationRequired = 511,
}
```

其实不难发现，这些都是在传输时定义的状态码，它大概率只能解释传输中的问题，比如你的服务是否正常返回一个`200`，你的服务不正常，返回一个`404`或者其他。而后端自定义的`responseCode`主要是为了定义业务问题，例如

```ts
const errCode = {
  40000: '请求参数错误',
  40001: '请求数据为空',
  40100: '未登录',
  40101: '无权限',
  40301: '访问屏蔽',
  50000: '系统内部异常',
}
```
简单来说，HTTP是传输层的定义，而responseCode是业务层的定义，二者互不相干。

为什么后端开发都喜欢自己定义 responseCode？ HTTP 状态码不够用吗？

![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/5c1b4749582b34fe3648eefa27ea0018.png)



这个我也不清楚具体原因，我是在ubuntu中挂了梯子的，浏览器可访问，但是使用curl显示拒绝连接。于是看到网上解决方法为写hosts

```bash
sudo bash -c 'echo "199.232.68.133 raw.githubusercontent.com" >> /etc/hosts'
```

下载raw.githubusercontent.com显示无法连接

> 使用虚拟机时我们可能经常需要复制粘贴文件夹，VMware自带的文件拖动复制粘贴的工具其实并不好用，使用共享文件夹可能是更好的选择，下面介绍在Windows下和Linux下使用




在虚拟机设置中->选项中设置共享文件夹
![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/9df095593e9bc0125d66046539948cd9.png)

Windows会共享在网络选项中

![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/26c077ba3bd37ed1799cecd0da50e14b.png)

Linux在mnt/hgfs下

![](https://picgo-img-repo.oss-cn-beijing.aliyuncs.com/img/df9e8fe2a590fcf24eb99ac9e34a05b2.png)