spring 處理request.getInputStream()輸入流只能讀取一次問題

一般我們會在InterceptorAdapter攔截器中對請求進行驗證

正常普通接口請求，request.getParameter()可以獲取，能多次讀取

如果我們的接口是用@RequestBody來接受數據，那么我們在攔截器中

需要讀取request的輸入流  ，因為 ServletRequest中getReader()和getInputStream()只能調用一次

這樣就會導致controller 無法拿到數據。

解決方法 ：

1、自定義一個類 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;//用於將流保存下來

    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、自定義 MyFilter  繼承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("開始");
    }

    @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("------------------------------請求報文----------------------------------");
            System.out.println(getParamsFromRequestBody((HttpServletRequest) requestWrapper));
            System.out.println("------------------------------請求報文----------------------------------");
            chain.doFilter(requestWrapper, response);
        }

    }
    /* *
     * 獲取請求體內容
     * @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配置過濾器

  <!--定義過濾器-->
    <filter>
        <!--定義過濾器攔截URL地址-->
        <filter-name>test2</filter-name>
        <!--過濾器的文件-->
        <filter-class>com.zhhy.hy2000interface.utils.filter.MyFilter</filter-class>
    </filter>
    <filter-mapping>
        <!--過濾器的名稱-->
        <filter-name>test2</filter-name>
        <!--過濾器負責攔截的URL-->
        <!-- /* 會把所有的請求攔截下來 -->
        <url-pattern>/*</url-pattern>

    </filter-mapping>

 

（如果是Springboot，使用注解即可）