解决No converter for XXX with preset Content-Type ‘application/octet-stream；charset=UTF-8‘

如题

我在后台封装下载excel的接口逻辑时，文件流关闭后响应返回success，但是后台报错

原因就是我系统整体封装的响应逻辑，所以我在下载文件后也返回了成功和失败的逻辑。但是并不支持。

try {

 List<ExportExcelData> excelDataList = getData(wo_id);  // 获取表体数据
 WriteCellStyle headWriteCellStyle = new WriteCellStyle();
 //设置头居中
 headWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);
//内容策略
WriteCellStyle contentWriteCellStyle = new WriteCellStyle();
//设置 水平居中
contentWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.LEFT);
HorizontalCellStyleStrategy horizontalCellStyleStrategy = new HorizontalCellStyleStrategy(headWriteCellStyle, contentWriteCellStyle);
response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
response.setCharacterEncoding("utf-8");
            // 这里URLEncoder.encode可以防止中文乱码 当然和easyexcel没有关系
String fileName = URLEncoder.encode(work_order+"报表导出测试", "UTF-8").replaceAll("\\+", "%20");
//            response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");
response.addHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");
response.addHeader("Access-Control-Expose-Headers", "Content-disposition");
// 合并策略
Map<String, List<RowRangeDto>> srategyMap = ExcelUtil.addMergeStrategy(excelDataList);
 // 这里需要设置不关闭流;
EasyExcel.write(response.getOutputStream(), ExportExcelData.class).autoCloseStream(Boolean.FALSE)
                    // 注册合并策略
                    .registerWriteHandler(new BizMergeStrategy(srategyMap))
                    .registerWriteHandler(ExcelUtil.CellStyleStrategy())
                    .sheet("ckd出货信息表")
                    .doWrite(excelDataList);
 return "文件下载成功";    // 改为void，不反回               
} catch (Exception e) {
            // 重置response
response.reset();
response.setContentType("application/json");
response.setCharacterEncoding("utf-8");
logger.error(e.getMessage());
 e.printStackTrace();
 return "文件下载失败";   // 改为void，不反回
        }

一个解决办法是并不返回提示，或者返回null即可避免此类报错。

但是很遗憾，如果我非要想返回成功或失败提示，目前还没有办法。

更新~

解决办法：加个转换器


import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;

import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;


@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedOrigins("*"). //允许跨域的域名，可以用*表示允许任何域名使用
                allowedMethods("*"). //允许任何方法（post、get等）
                allowedHeaders("*"). //允许任何请求头
                allowCredentials(true). //带上cookie信息
                exposedHeaders(HttpHeaders.SET_COOKIE).maxAge(3600L); //maxAge(3600)表明在3600秒内，不需要再发送预检验请求，可以缓存该结果
    }

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        //调用父类的配置
        WebMvcConfigurer.super.configureMessageConverters(converters);
        //创建FastJson的消息转换器
        FastJsonHttpMessageConverter convert = new FastJsonHttpMessageConverter();
        //创建FastJson的配置对象
        FastJsonConfig config = new FastJsonConfig();
        //对Json数据进行格式化
        config.setSerializerFeatures(SerializerFeature.PrettyFormat,
                SerializerFeature.WriteNullStringAsEmpty,
                SerializerFeature.WriteNullNumberAsZero,
                SerializerFeature.WriteNullListAsEmpty,
                SerializerFeature.WriteNullBooleanAsFalse,
                SerializerFeature.WriteMapNullValue,
                //禁止循环引用
                SerializerFeature.DisableCircularReferenceDetect);
        config.setDateFormat("yyyy-MM-dd HH:mm:ss");
        config.setCharset(Charset.forName("UTF-8"));
        convert.setFastJsonConfig(config);
        convert.setSupportedMediaTypes(getSupportedMediaTypes());
        converters.add(convert);
    }

    public List<MediaType> getSupportedMediaTypes() {
        //创建fastJson消息转换器
        List<MediaType> supportedMediaTypes = new ArrayList<>();
        supportedMediaTypes.add(MediaType.APPLICATION_JSON);
        supportedMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
        supportedMediaTypes.add(MediaType.APPLICATION_ATOM_XML);
        supportedMediaTypes.add(MediaType.APPLICATION_FORM_URLENCODED);
        supportedMediaTypes.add(MediaType.APPLICATION_OCTET_STREAM);
        supportedMediaTypes.add(MediaType.APPLICATION_PDF);
        supportedMediaTypes.add(MediaType.APPLICATION_RSS_XML);
        supportedMediaTypes.add(MediaType.APPLICATION_XHTML_XML);
        supportedMediaTypes.add(MediaType.APPLICATION_XML);
        supportedMediaTypes.add(MediaType.IMAGE_GIF);
        supportedMediaTypes.add(MediaType.IMAGE_JPEG);
        supportedMediaTypes.add(MediaType.IMAGE_PNG);
        supportedMediaTypes.add(MediaType.TEXT_EVENT_STREAM);
        supportedMediaTypes.add(MediaType.TEXT_HTML);
        supportedMediaTypes.add(MediaType.TEXT_MARKDOWN);
        supportedMediaTypes.add(MediaType.TEXT_PLAIN);
        supportedMediaTypes.add(MediaType.TEXT_XML);
        supportedMediaTypes.add(MediaType.ALL);
        return supportedMediaTypes;
    }

}