Spring MVC中如何为@ControllerAdvice/@ExceptionHandler设置UTF-8编码？

下面是几种可行的解决方案，按推荐优先级排序：

方法1：配置全局消息转换器（推荐） #

通过Java配置统一设置Spring MVC的消息转换器字符集，确保所有响应（包括异常响应）都使用UTF-8编码：

@Configuration
@EnableWebMvc
public class WebMvcConfig implements WebMvcConfigurer {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        MappingJackson2HttpMessageConverter jsonConverter = new MappingJackson2HttpMessageConverter();
        jsonConverter.setDefaultCharset(StandardCharsets.UTF_8);
        
        List<MediaType> supportedMediaTypes = new ArrayList<>();
        supportedMediaTypes.add(MediaType.APPLICATION_JSON);
        jsonConverter.setSupportedMediaTypes(supportedMediaTypes);
        
        converters.add(jsonConverter);
    }
}

方法2：在异常处理中手动设置响应头编码 #

直接在handleConflict方法里给响应头指定UTF-8编码：

@ControllerAdvice
public class RestResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {
    @ExceptionHandler(value = {
        NoSuchElementException.class,
        IllegalArgumentException.class,
        ServiceUnavailableException.class})
    protected ResponseEntity<Object> handleConflict(RuntimeException ex, WebRequest req) {
        String responseBody = ex.getMessage();
        HttpHeaders headers = new HttpHeaders();
        // 设置响应内容类型为带UTF-8编码的JSON
        headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
        
        return handleExceptionInternal(ex, responseBody, headers, HttpStatus.BAD_REQUEST, req);
    }
}

方法3：重写handleExceptionInternal统一处理编码 #

如果有多个异常处理方法，重写父类的handleExceptionInternal方法，统一为所有异常响应设置编码：

@ControllerAdvice
public class RestResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {
    
    @ExceptionHandler(value = {
        NoSuchElementException.class,
        IllegalArgumentException.class,
        ServiceUnavailableException.class})
    protected ResponseEntity<Object> handleConflict(RuntimeException ex, WebRequest req) {
        String responseBody = ex.getMessage();
        return handleExceptionInternal(ex, responseBody, new HttpHeaders(), HttpStatus.BAD_REQUEST, req);
    }

    @Override
    protected ResponseEntity<Object> handleExceptionInternal(
            Exception ex, Object body, HttpHeaders headers, HttpStatus status, WebRequest request) {
        headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
        return super.handleExceptionInternal(ex, body, headers, status, request);
    }
}

额外检查：Tomcat编码配置 #

确保Tomcat的server.xml中Connector节点配置了UTF-8编码，避免容器层面的编码问题：

<Connector port="8080" protocol="HTTP/1.1"
           connectionTimeout="20000"
           redirectPort="8443"
           URIEncoding="UTF-8"
           useBodyEncodingForURI="true"/>

内容的提问来源于stack exchange，提问作者cognosce