spring 处理request.getInputStream()输入流只能读取一次问题

一般我们会在InterceptorAdapter拦截器中对请求进行验证

正常普通接口请求，request.getParameter()可以获取，能多次读取

如果我们的接口是用@RequestBody来接受数据，那么我们在拦截器中

需要读取request的输入流  ，因为 ServletRequest中getReader()和getInputStream()只能调用一次

这样就会导致controller 无法拿到数据。

解决方法 ：

1、自定义一个类 BodyReaderHttpServletRequestWrapper.java 

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

import org.springframework.util.StreamUtils;

/**
 * @author WBG
 * @date 2020/6/22 10:42
 * @describe
 */
public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper{

    private byte[] requestBody = null;//用于将流保存下来

    public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        requestBody = StreamUtils.copyToByteArray(request.getInputStream());

    }

    @Override
    public ServletInputStream getInputStream() throws IOException {

        final ByteArrayInputStream bais = new ByteArrayInputStream(requestBody);

        return new ServletInputStream() {

            @Override
            public int read() throws IOException {
                return bais.read();
            }

            @Override
            public boolean isFinished() {
                return false;
            }

            @Override
            public boolean isReady() {
                return false;
            }

            @Override
            public void setReadListener(ReadListener readListener) {

            }
        };
    }

    @Override
    public BufferedReader getReader() throws IOException{
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }
}

2、自定义 MyFilter  继承Filter

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.BufferedReader;
import java.io.IOException;

/**
 * @author WBG
 * @date 2020/6/22 14:32
 * @describe
 */
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("开始");
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        ServletRequest requestWrapper=null;
        if(request instanceof HttpServletRequest) {
            requestWrapper=new BodyReaderHttpServletRequestWrapper((HttpServletRequest)request);
        }
        if(requestWrapper==null) {
            chain.doFilter(request, response);
        }else {
            System.out.println("------------------------------请求报文----------------------------------");
            System.out.println(getParamsFromRequestBody((HttpServletRequest) requestWrapper));
            System.out.println("------------------------------请求报文----------------------------------");
            chain.doFilter(requestWrapper, response);
        }

    }
    /* *
     * 获取请求体内容
     * @return
     * @throws IOException
     */

    private String getParamsFromRequestBody(HttpServletRequest request) throws IOException {
        BufferedReader br = null;
        String listString = "";
        try {
            br = request.getReader();

            String str = "";

            while ((str = br.readLine()) != null) {
                listString += str;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return listString;
    }

    @Override
    public void destroy() {
        System.out.println("destroy");
    }
}

3、web.xm配置过滤器

  <!--定义过滤器-->
    <filter>
        <!--定义过滤器拦截URL地址-->
        <filter-name>test2</filter-name>
        <!--过滤器的文件-->
        <filter-class>com.zhhy.hy2000interface.utils.filter.MyFilter</filter-class>
    </filter>
    <filter-mapping>
        <!--过滤器的名称-->
        <filter-name>test2</filter-name>
        <!--过滤器负责拦截的URL-->
        <!-- /* 会把所有的请求拦截下来 -->
        <url-pattern>/*</url-pattern>

    </filter-mapping>

（如果是Springboot，使用注解即可）