spring boot 解决后台返回 json 到前台中文乱码之后出现返回json数据报错 500：no convertter for return value of type

Posted 2020-11-19 设计师小萍儿

问题描述

• spring Boot 中文返回给浏览器乱码 解析成问号？？ fastJson jackJson
• spring boot 新增配置解决后台返回 json 到前台中文乱码之后,出现返回json数据报错：no convertter for return value of type
• 注释掉解决中文乱码的问题之后返回对象json正常
• Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException:
  No converter found for return value of type: class www.it399.com.controller.file.ResultBean

解决中文乱码的配置

@Configuration
@EnableWebMvc
@ComponentScan
public class MvcConfiguration extends WebMvcConfigurerAdapter {

    @Bean
    public HttpMessageConverter<String> responseBodyConverter(){
        StringHttpMessageConverter converter = new StringHttpMessageConverter(Charset.forName("UTF-8"));
        return converter;
    }

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        super.configureMessageConverters(converters);
        //解决中文乱码
        converters.add(responseBodyConverter());
        //解决 添加解决中文乱码后 上述配置之后，返回json数据直接报错 500：no convertter for return value of type
        converters.add(messageConverter());
    }

}

除了上述配置之后还有添加MappingJackson2HttpMessageConverter

 @Bean
    public MappingJackson2HttpMessageConverter messageConverter() {
        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
        converter.setObjectMapper(getObjectMapper());
        return converter;
    }

注意:responseBodyConverter和MappingJackson2HttpMessageConverter如果分开配置要确保前者不被覆盖，不然就会出现返回springboot返回json正常，但是返回中文乱码，或者返回中文不乱吗，但是返回对象或者json异常。

解决springboot范湖中文乱码和返回json 500错误的完整代码

/**
 * spring boot 解决后台返回 json 到前台出现中文乱码的问题
 * 在线助手博客 http://www.it399.com/blog/index.jsp
 */
@Configuration
@EnableWebMvc
@ComponentScan
public class MvcConfiguration extends WebMvcConfigurerAdapter {

    @Bean
    public HttpMessageConverter<String> responseBodyConverter(){
        StringHttpMessageConverter converter = new StringHttpMessageConverter(Charset.forName("UTF-8"));
        return converter;
    }


    @Bean
    public ObjectMapper getObjectMapper() {
        return new ObjectMapper();
    }


    @Bean
    public MappingJackson2HttpMessageConverter messageConverter() {
        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
        converter.setObjectMapper(getObjectMapper());
        return converter;
    }



    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        super.configureMessageConverters(converters);
        //解决中文乱码
        converters.add(responseBodyConverter());
        //解决 添加解决中文乱码后 上述配置之后，返回json数据直接报错 500：no convertter for return value of type
        converters.add(messageConverter());
    }

}

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原文链接 http://www.it399.com/blog/web/201805081017