request多次读取inputStream

https://howtodoinjava.com/servlets/httpservletrequestwrapper-example-read-request-body/

 

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import javax.servlet.ReadListener; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import java.io.*;   public class OauthRequestWrapper extends HttpServletRequestWrapper {     private final String body;       public OauthRequestWrapper(HttpServletRequest request) throws IOException     {         //So that other request method behave just like before         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;                 }             }         }         //Store request pody content in 'body' variable         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();             }               @Override             public boolean isFinished() {                 return byteArrayInputStream.available()==0;             }               @Override             public boolean isReady() {                 return byteArrayInputStream.available()>0;             }               @Override             public void setReadListener(ReadListener readListener) {               }         };         return servletInputStream;     }       @Override     public BufferedReader getReader() throws IOException {         return new BufferedReader(new InputStreamReader(this.getInputStream()));     }       //Use this method to read the request body N times     public String getBody() {         return this.body;     } }

　　

filter中调用

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

public class OauthAuthenticationFilter 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 OauthRequestWrapper((HttpServletRequest) request);
        }
        if(requestWrapper == null) {
            chain.doFilter(request, response);
        } else {
            chain.doFilter(requestWrapper, response);
        }
    }

    @Override
    public void destroy() {

    }
}