【SpringBoot统一返回处理遇到的问题cannot be cast to java.lang.String】

具体产生原因请参考以下文章了解: https://www.jianshu.com/p/0f16c9f1760e

解决办法:

    if (body instanceof String){//string类型单独处理try {if (response instanceof ServletServerHttpResponse) {response.getHeaders().put("content-type", Lists.newArrayList(new String[]{"application/json; charset=UTF-8"}));}return this.converter.getObjectMapper().writeValueAsString(ResultData.success(body));} catch (JsonProcessingException var8) {throw new RuntimeException(var8);}}else {return ResultData.success(body);}}

其中this.converter 在上方引入

@Autowiredprivate MappingJackson2HttpMessageConverter converter;

全部代码

@ControllerAdvice(basePackages = "com.***.controller")
public class UnifiedReturnAdvice implements ResponseBodyAdvice<Object> {@Autowiredprivate MappingJackson2HttpMessageConverter converter;@Overridepublic boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {return returnType.getDeclaringClass().getName().contains("com.***.controller");}@Overridepublic Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {Class<?> containingClass = returnType.getContainingClass();//判断进入的方法对应的接口上的注解boolean isContainUnifiedReturn = containingClass.isAnnotationPresent(UnifiedReturn.class);
//       判断的是进入的方法: returnType.hasMethodAnnotation(UnifiedReturn.class);if (!isContainUnifiedReturn) {return body;}if (body instanceof String){//string类型单独处理try {if (response instanceof ServletServerHttpResponse) {response.getHeaders().put("content-type", Lists.newArrayList(new String[]{"application/json; charset=UTF-8"}));}return this.converter.getObjectMapper().writeValueAsString(ResultData.success(body));} catch (JsonProcessingException var8) {throw new RuntimeException(var8);}}else {return ResultData.success(body);}}
}