feign调用返回ModelAndView方式

服务端接口返回的类型为ModelAndView时，feign客户端调用会报错，原因是因为HttpMessageConverter解析不能解析类型为text/html的数据类型

解决方法：添加text/html解析
代码：
创建转换类：


import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.converter.AbstractHttpMessageConverter;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.http.converter.HttpMessageNotWritableException;
import org.springframework.util.StreamUtils;
import org.springframework.web.servlet.ModelAndView;

import java.io.IOException;
import java.nio.charset.Charset;

    public class PayHttpMessageConverter1 extends AbstractHttpMessageConverter<Object> {
        public PayHttpMessageConverter1() {
            super(MediaType.TEXT_HTML);
        }
        @Override
        protected boolean supports(Class<?> aClass) {
            return true;
        }
        @Override
        protected Object readInternal(Class<?> aClass, HttpInputMessage httpInputMessage) throws IOException, HttpMessageNotReadableException {
            String text = StreamUtils.copyToString(httpInputMessage.getBody(), Charset.forName("UTF-8"));
            return new ModelAndView(new MyPlainHtmlView(text ));
        }
        @Override
        protected void writeInternal(Object o, HttpOutputMessage httpOutputMessage) throws IOException, HttpMessageNotWritableException {
        }
}

解释：将响应流读成字符串，然后将字符串转为ModelAndView

import org.springframework.web.servlet.View;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.util.Map;

public class MyPlainHtmlView implements View {
    private final String htmlDocument;

    public MyPlainHtmlView(String htmlDocument) {
        this.htmlDocument = htmlDocument;
    }

    @Override
    public String getContentType() {
        return null;
    }

    @Override
    public void render(Map<String, ?> map, javax.servlet.http.HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
        ServletOutputStream out = httpServletResponse.getOutputStream();
        out.write(this.htmlDocument.getBytes("utf-8"));
    }
}

注意canRead和read就行
在 canRead 方法中判断了是不是 text/html 类型，是的话就会返回true，Spring 就会调用 read，用来将字节流中的数据转换成具体实体，aClass就是我们最终想要得到的实例对象的Class

然后将转换类添加到getMessageConverters中

@Bean
public RestTemplate restTemplate(){
    RestTemplate restTemplate = new RestTemplate();
    restTemplate.getMessageConverters().add(new PayHttpMessageConverter1());
    return  restTemplate;
}

feign调用返回ModelAndView方式

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