例如调用小程序登录接口时报以下错误

GET https://api.weixin.qq.com/sns/jscode2session?appid=APPID&secret=SECRET&js_code=JSCODE&grant_type=authorization_code

org.springframework.web.client.RestClientException: Could not extract response: no suitable HttpMessageConverter found for response type [class com.thy.common.MpUserInfo] and content type [text/plain]

解决办法

1.添加WxMappingJackson2HttpMessageConverter

import java.util.ArrayList;
import java.util.List;

import org.springframework.http.MediaType;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;

public class WxMappingJackson2HttpMessageConverter extends MappingJackson2HttpMessageConverter {
    public WxMappingJackson2HttpMessageConverter(){
        List<MediaType> mediaTypes = new ArrayList<>();
        mediaTypes.add(MediaType.TEXT_PLAIN);
        mediaTypes.add(MediaType.TEXT_HTML);  //加入text/html类型的支持
        setSupportedMediaTypes(mediaTypes);// tag6
    }
}

2.修改注入的RestTemplate

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class RestConf {
    @Bean
    public RestTemplate getRestTemplate() {
        RestTemplate restTemplate = new RestTemplate();
        //追加原因：https://blog.csdn.net/kinginblue/article/details/52706155
        restTemplate.getMessageConverters().add(new WxMappingJackson2HttpMessageConverter());
        return restTemplate;
    }
}

原因参考

https://blog.csdn.net/kinginblue/article/details/52706155