Spring多次request.getReader()解决方法

Spring多次request.getReader()解决方法

ServletRequest的getReader和getInputStream只能调用一次

开发中遇到一个需求,对http请求进行打点,其中有个字段是请求body

本来想的是写一个拦截器拦截所有请求,读取请求中的body,然后写入MQ

        StringBuilder data = new StringBuilder();
        String line;
        BufferedReader reader;
        reader = request.getReader();
        while (null != (line = reader.readLine())) {
            data.append(line);
        }

然后报错了requesst.getReader只能调用一次,因为@RequestBody中读取过一次,拦截器中在读取一次会报错.

网上有说重写HttpServletRequestWrapper备份

多方查找发现Spring自带了一个对HttpServletRequestWrapper的重写(org.springframework.web.util.ContentCachingRequestWrapper),可以满足需求,记录一下解决方法.

下面demo

编写filter,把request设置成ContentCachingRequestWrapper

import org.springframework.web.filter.GenericFilterBean;
import org.springframework.web.util.ContentCachingRequestWrapper;
import java.io.IOException;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
public class CachingRequestBodyFilter extends GenericFilterBean {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
        throws IOException, ServletException {
        HttpServletRequest currentRequest = (HttpServletRequest) request;
        ContentCachingRequestWrapper wrappedRequest = new ContentCachingRequestWrapper(currentRequest);
        chain.doFilter(wrappedRequest, response);
    }
}

使filter生效

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class FilterConfig {

    @Bean
    public FilterRegistrationBean<CachingRequestBodyFilter> filterRegistration() {
        FilterRegistrationBean<CachingRequestBodyFilter> registration = new FilterRegistrationBean<>(new CachingRequestBodyFilter());
        registration.setOrder(2);
        return registration;
    }
}

使用

    ContentCachingRequestWrapper wrapper = org.springframework.web.util.WebUtils.getNativeRequest(request,ContentCachingRequestWrapper.class);
    if(Objects.isNull(wrapper)){
        return null;
    }
    String s=new String(wrapper.getContentAsByteArray());

注意

ContentCachingRequestWrapper 只有request调用过getReader或getInputStream时才ContentAsByteArray有数据,
当controller没有@RequestBody时使用ContentCachingRequestWrapper是读取不到数据的,
需要直接调用处理

        StringBuilder data = new StringBuilder();
        String line;
        BufferedReader reader;
        reader = request.getReader();
        while (null != (line = reader.readLine())) {
            data.append(line);
        }