解决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）

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