HttpServetRequest讀取body只能一次的問題

HTTP請求中的是字符串數據：

//字符串讀取
 
void charReader(HttpServletRequest request) {
    BufferedReader br = request.getReader();
    String str, wholeStr = "";
    while((str = br.readLine()) != null){
       wholeStr += str;
    }
    System.out.println(wholeStr);
}
//二進制讀取
 
void binaryReader(HttpServletRequest request) {
     int len = request.getContentLength();
     ServletInputStream iii = request.getInputStream();
16      byte[] buffer = new byte[len];
     iii.read(buffer, 0, len);
}

注意：

request.getInputStream();   request.getReader();  和request.getParameter("key");

這三個函數中任何一個函數執行一次后（可正常讀取body數據），之后再執行就無效了。

 

解決方法： 包裝HttpServletRequest對象，緩存body數據，再次讀取的時候將緩存的值寫出

package com.nd.sdp.formatastic.common.interceptor;

import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;

/**
 * @author weihainan.
 * @since 0.1 created on 2017/2/23.
 */
public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {

    private final String body;

    public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        try {
            InputStream inputStream = request.getInputStream();
            if (inputStream != null) {
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                stringBuilder.append("");
            }
        } catch (IOException ex) {
            throw ex;
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException ex) {
                    throw ex;
                }
            }
        }
        body = stringBuilder.toString();
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());
        ServletInputStream servletInputStream = new ServletInputStream() {
            public int read() throws IOException {
                return byteArrayInputStream.read();
            }
        };
        return servletInputStream;
    }

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

    public String getBody() {
        return this.body;
    }
}

 

使用Filter替換HttpServletRequest對象

package com.nd.sdp.formatastic.common.interceptor;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

/**
 * @author weihainan.
 * @since 0.1 created on 2017/2/23.
 */
@WebFilter(filterName = "httpServletRequestWrapperFilter", urlPatterns = "/*")
public class HttpServletRequestWrapperFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @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 (null == requestWrapper) {
            chain.doFilter(request, response);
        } else {
            chain.doFilter(requestWrapper, response);
        }

    }

    @Override
    public void destroy() {

    }
}