【GitLab】Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableExcep

问题：

这个是在Spring Cloud配置中心（Config Server）拉取配置文件时引起的报错。

公司Config Server使用的版本库是GitLab。在启动时会访问微服务配置的GitLab地址，正常的情况下在GitLab中需要配置Webhooks信息，系统访问GitLab后会对Webhooks配置地址进行回调处理，报错就发生在微服务解析回调信息时，报错内容如下：

Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: JSON parse 
    error: Cannot deserialize instance of `java.lang.String` out of START_OBJECT token; nested exception is 
    com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of
     `java.lang.String` out of START_OBJECT token at [Source: (PushbackInputStream); line: 1, column: 449]
     (through reference chain: java.util.LinkedHashMap["project"])

解决：

这个错误是因为GitLab11.10之后，使用Webhook返回响应JSON对象无法使用Jackson进行反序列化导致。

因此只需要在Spring Cloud配置中心（Config Server）中增加过滤器进行JSON数据序列化就可以了。

UrlFilter.java

package io.yzh.component.filter;
import java.io.BufferedReader;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import io.yzh.component.wrapper.CustometRequestWrapper;
/** * @Function url过滤器 */
@WebFilter(filterName = "urlFilter", urlPatterns = "/*")
@Order(1)
@Component
public class UrlFilter implements Filter { 
    public static final Logger logger = LoggerFactory.getLogger(UrlFilter.class);
    @Override
    public void init(FilterConfig filterConfig) throws ServletException { 
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { 
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String url = new String(httpServletRequest.getRequestURI());
        // 只过滤/actuator/bus-refresh请求
        if (!url.endsWith("/bus-refresh")) { 
            chain.doFilter(request, response);
            return;
        }
        CustometRequestWrapper requestWrapper = new CustometRequestWrapper(httpServletRequest);
        chain.doFilter(requestWrapper, response);
    }
    @Override
    public void destroy() { 
    }
    /** * 以char形式读取 * * @param request * @return */
    public static String readAsChars(HttpServletRequest request) { 
        BufferedReader br = null;
        StringBuilder sb = new StringBuilder("");
        try { 
            br = request.getReader();
            String str;
            while ((str = br.readLine()) != null) { 
                sb.append(str);
            }
            br.close();
        } catch (IOException e) { 
            logger.info(" --------- An exception occurred : " + e.getMessage() + " --------- ");
        } finally { 
            if (null != br) { 
                try { 
                    br.close();
                } catch (IOException e) { 
                    logger.info(" --------- An exception occurred : " + e.getMessage() + " --------- ");
                }
            }
        }
        return sb.toString();
    }
}

CustometRequestWrapper.java

package io.yzh.component.wrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
/** * @Function 自定义请求包装器 */
public class CustometRequestWrapper extends HttpServletRequestWrapper { 
    public CustometRequestWrapper(HttpServletRequest request) { 
        super(request);
    }
    /** * 以流输出 */
    @Override
    public ServletInputStream getInputStream() throws IOException { 
        byte[] bytes = new byte[0];
        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(bytes);
        return new ServletInputStream() { 
            @Override
            public boolean isFinished() { 
                return byteArrayInputStream.read() == -1 ? true : false;
            }
            @Override
            public boolean isReady() { 
                return false;
            }
            @Override
            public void setReadListener(ReadListener readListener) { 
            }
            @Override
            public int read() throws IOException { 
                return byteArrayInputStream.read();
            }
        };
    }
}