利用HttpServletRequestWrapper对HttpServletRequest进行封装的方法

最新推荐文章于 2024-01-26 15:48:06 发布

原创最新推荐文章于 2024-01-26 15:48:06 发布 · 7.3k 阅读

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本文详细阐述了在处理HTTP请求时，如何通过HttpServletRequest的封装实现对于inputStream内容的权限验证，确保请求的安全性。文章重点介绍了Filter中对inputStream的读取方式，以及在Controller层如何提取并处理这些内容，最终实现对post/put/delete请求的有效响应。

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首先，说明几个类和方法的关系： class HttpServletRequestWrapper extends ServletRequestWrapper implements HttpServletRequest

在Filter中由于需要的对于inputStream的内容进行权限验证，我们必须将所有input内容读取出来，但是在Controller层中程序同样需要提取input的内容，进而执行对应的post/put/delete请求，因此，我们在此对HttpServletRequest进行了封装，并对封装后的HttpServletRequestWrapper的getInputStream方法进行了重载，保证重载后的方法可以再次读取到inputStream中的所有内容。

package com.jeremyxu.xinterface.wrapper;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.pptv.cloud.ppsync.common.exception.CloudRuntimeException;
import com.pptv.cloud.ppsync.common.util.StringUtils;

public class FilterRequestWrapper extends HttpServletRequestWrapper {
   private static Logger log = LoggerFactory.getLogger(FilterRequestWrapper.class);

    private final String payload;
    private String encoding = null;

    public FilterRequestWrapper (HttpServletRequest request) {

        super(request);
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        String encoding = request.getCharacterEncoding();
        try {

// read the payload into the StringBuilder

//按照正确的encoding，将inputStream中的内容写入到String中

            InputStream inputStream = request.getInputStream();
            if (inputStream != null) {
               if (StringUtils.isEmpty(encoding)) {
                   bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
               } else {
                   this.encoding = encoding;
                   bufferedReader = new BufferedReader(new InputStreamReader(inputStream, encoding));
               }
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                // make an empty string since there is no payload
                stringBuilder.append("");
            }
        } catch (IOException ex) {
            log.error("Error reading the request payload", ex);
            throw new CloudRuntimeException("Error reading the request payload", ex);
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException iox) {
                    // ignore
                }
            }
        }
        payload = stringBuilder.toString();
    }

    public String getPayload() {
       return this.payload;
    }

@Override

重载getInputStream方法，获取ServletInputStream流

    public ServletInputStream getInputStream ()
        throws IOException {

        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(
               StringUtils.isEmpty(encoding)? payload.getBytes() : payload.getBytes(encoding));

        ServletInputStream inputStream = new ServletInputStream() {
            public int read ()
                throws IOException {
                return byteArrayInputStream.read();
            }
        };
        return inputStream;
    }
}