解决SpringBoot请求返回字符串中文乱码的问题

ResponseEntity.status(HttpStatus.NOT_FOUND)
  .body(String.format("未找到相应id %d 的记录", id));

@Configuration
@EnableWebMvc
public class MyMvcConfig implements WebMvcConfigurer {
 
    @Bean
    public HttpMessageConverter<String> responseBodyStringConverter() {
        StringHttpMessageConverter converter = new StringHttpMessageConverter(StandardCharsets.UTF_8);
        return converter;
    }
 
 
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters){
        converters.add(responseBodyStringConverter());
    }
}

//解决中文文件名的乱码问题
String utf8 = StandardCharsets.UTF_8.name();
try {
    downloadFileName = URLEncoder.encode(downloadFileName, utf8);
} catch (UnsupportedEncodingException e) {
    //
}
 
return ResponseEntity.ok()
        .contentType(MediaType.APPLICATION_OCTET_STREAM)
        .header(HttpHeaders.CONTENT_DISPOSITION,
                "attachment; filename* = " + utf8 + "''" + downloadFileName)
        .body(new UrlResource(downloadFile.toURI()));

    protected final List<HttpMessageConverter<?>> getMessageConverters() {
        if (this.messageConverters == null) {
            this.messageConverters = new ArrayList();
            this.configureMessageConverters(this.messageConverters);
            if (this.messageConverters.isEmpty()) {
                this.addDefaultHttpMessageConverters(this.messageConverters);
            }
 
            this.extendMessageConverters(this.messageConverters);
        }
 
        return this.messageConverters;
    }

   @Bean
    public HttpMessageConverter<String> responseBodyStringConverter() {
        StringHttpMessageConverter converter = new StringHttpMessageConverter(StandardCharsets.UTF_8);
        return converter;
    }
 
    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        List<StringHttpMessageConverter> stringHttpMessageConverters = converters.stream()
                .filter(converter -> converter.getClass().equals(StringHttpMessageConverter.class))
                .map(converter -> (StringHttpMessageConverter) converter)
                .collect(Collectors.toList());
 
        if (stringHttpMessageConverters.isEmpty()) {
            converters.add(responseBodyStringConverter());
        } else {
            stringHttpMessageConverters.forEach(converter -> converter.setDefaultCharset(StandardCharsets.UTF_8));
        }
    }

	protected JsonEncoding getJsonEncoding(@Nullable MediaType contentType) {
		if (contentType != null && contentType.getCharset() != null) {
			Charset charset = contentType.getCharset();
			for (JsonEncoding encoding : JsonEncoding.values()) {
				if (charset.name().equals(encoding.getJavaName())) {
					return encoding;
				}
			}
		}
		return JsonEncoding.UTF8;
	}

	/**
	 * A String equivalent of {@link MediaType#APPLICATION_JSON_UTF8}.
	 * @deprecated as of 5.2 in favor of {@link #APPLICATION_JSON_VALUE}
	 * since major browsers like Chrome
	 * <a href="https://bugs.chromium.org/p/chromium/issues/detail?id=438464" rel="external nofollow" >
	 * now comply with the specification</a> and interpret correctly UTF-8 special
	 * characters without requiring a {@code charset=UTF-8} parameter.
	 */
	@Deprecated
	public static final String APPLICATION_JSON_UTF8_VALUE = "application/json;charset=UTF-8";