SpringBoot项目, 拦截器获取Post方法的请求body

1). 存在问题

流只能读取一次

2). 目标

多次读取流

3). 解决方法

创建包装类

4). RequestWrapper

package com.mazaiting.redeye.wrapper;

import com.mazaiting.redeye.utils.StreamUtil;
import lombok.extern.slf4j.Slf4j;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;

/***
 * @author mazaiting
 * @date 2019-06-27
 * @decription HttpServletRequest 包装器
 * 解决: request.getInputStream()只能读取一次的问题
 * 目标: 流可重复读
 */
@Slf4j
public class RequestWrapper extends HttpServletRequestWrapper {
    /**
     * 日志
     */
    private static final Logger mLogger = LoggerFactory.getLogger(RequestWrapper.class);

    /**
     * 请求体
     */
    private String mBody;

    public RequestWrapper(HttpServletRequest request) {
        super(request);
        // 将body数据存储起来
        mBody = getBody(request);
    }

    /**
     * 获取请求体
     * @param request 请求
     * @return 请求体
     */
    private String getBody(HttpServletRequest request) {
        try {
            return StreamUtil.getString(request.getInputStream());
        } catch (IOException e) {
            mLogger.debug(e.getMessage());
            throw new RuntimeException(e);
        }
    }

    /**
     * 获取请求体
     * @return 请求体
     */
    public String getBody() {
        return mBody;
    }

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

    @Override
    public ServletInputStream getInputStream() throws IOException {
        // 创建字节数组输入流
        final ByteArrayInputStream bais = new ByteArrayInputStream(mBody.getBytes(Charset.defaultCharset()));

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

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

            @Override
            public void setReadListener(ReadListener readListener) {

            }

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

设置过滤器(必须)

@Component
@WebFilter(filterName = "HttpServletRequestFilter", urlPatterns = "/")
@Order(10000)
public class HttpServletRequestFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        ServletRequest requestWrapper = null;
        if(servletRequest instanceof HttpServletRequest) {
            requestWrapper = new RequestWrapper((HttpServletRequest) servletRequest);
        }
        //获取请求中的流如何，将取出来的字符串，再次转换成流，然后把它放入到新request对象中
        // 在chain.doFiler方法中传递新的request对象
        if(null == requestWrapper) {
            filterChain.doFilter(servletRequest, servletResponse);
        } else {
            filterChain.doFilter(requestWrapper, servletResponse);
        }
    }

    @Override
    public void destroy() {

    }
}

6). 使用

/***
 *
 * @author mazaiting
 * @date 2019-06-26
 * @decription Session 拦截器
 */
public class SessionInterceptor implements HandlerInterceptor {

    /**
     * 日志
     */
    private static final Logger mLogger = LoggerFactory.getLogger(SessionInterceptor.class);

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        mLogger.debug("SessionInterceptor");
        // 获取地址
        String url = request.getRequestURL().toString();
        mLogger.debug("url: " + url);
        // 获取 session
        HttpSession session = request.getSession();
        String id = session.getId();
        mLogger.debug("sessionId: " + id);
        String requestMethod = request.getMethod();
        mLogger.debug("requestMethod: " + requestMethod);
        String servletPath = request.getServletPath();
        mLogger.debug("servletPath: " + servletPath);

        if (isJson(request)) {
            String body = new RequestWrapper(request).getBody();
            mLogger.debug("body: " + body);
        }

        return true;
    }

    /**
     * 判断本次请求的数据类型是否为json
     *
     * @param request request
     * @return true: 是 JSON 数据; false: 非 json 数据
     */
    private boolean isJson(HttpServletRequest request) {
        if (request.getContentType() != null) {
            return request.getContentType().equals(MediaType.APPLICATION_JSON_VALUE) ||
                    request.getContentType().equals(MediaType.APPLICATION_JSON_UTF8_VALUE);
        }

        return false;
    }
}