April 14, 2021

HttpServlet stream closed : inputstream or reader can only be read once [solution]

The code will be working fine. description is not posted

Copy paste the following code

package com.javabelazy.filter;
 
import javax.servlet.http.HttpServletRequest;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
 
public class HttpHelper {
    public static String getBodyString(HttpServletRequest request) throws IOException {
        StringBuilder sb = new StringBuilder();
        InputStream inputStream = null;
        BufferedReader reader = null;
        try {
            inputStream = request.getInputStream();
            reader = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("UTF-8")));
            String line = "";
            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return sb.toString();
    }
}


A wrapper class

package com.javabelazy.filter;
 
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
 
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
 
public class RequestReaderHttpServletRequestWrapper extends HttpServletRequestWrapper{
 
    private final byte[] body;
 
    public RequestReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        body = HttpHelper.getBodyString(request).getBytes(Charset.forName("UTF-8"));
    }
 
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }
 
    @Override
    public ServletInputStream getInputStream() throws IOException {
 
        final ByteArrayInputStream bais = new ByteArrayInputStream(body);
 
        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) {
 
            }
        };
    }
}

Filter class

package com.javabelazy.filter;
 
 
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
 
 
public class HttpServletRequestReplacedFilter implements Filter {
    @Override
    public void destroy() {
 
    }
 
    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain chain) throws IOException, ServletException {
        ServletRequest requestWrapper = null;
        if(request instanceof HttpServletRequest) {
            requestWrapper = new RequestReaderHttpServletRequestWrapper((HttpServletRequest) request);
        }
        //Get the stream in the request, convert the fetched string into a stream, and put it into the new request object.
                 // Pass the new request object in the chain.doFiler method
        if(requestWrapper == null) {
            chain.doFilter(request, response);
        } else {
            chain.doFilter(requestWrapper, response);
        }
    }
 
    @Override
    public void init(FilterConfig arg0) throws ServletException {
 
    }
}

Add this to config

@Bean
public FilterRegistrationBean httpServletRequestReplacedRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new HttpServletRequestReplacedFilter());
registration.addUrlPatterns("/*");
        registration.addInitParameter("paramName", "paramValue");
registration.setName("httpServletRequestReplacedFilter");
registration.setOrder(1);
return registration;
}


you can make the filterregistrationBean a generic class


FilterRegistrationBean<HttpServletRequestReplacedFilter> registration = new FilterRegistrationBean();


or use the below annotation for filter class

 @Order(1)//Set the loading order of this class in the spring container
@Aspect
@Configuration

you can omit configuring bean in config class


Thanks for reading

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