封装Request，提供多次读取数据

最新推荐文章于 2025-01-09 22:00:20 发布

Panaon

最新推荐文章于 2025-01-09 22:00:20 发布

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分类专栏： Java 文章标签： RequestWrapper 重复读取Request数据流

本文链接：https://blog.youkuaiyun.com/Panaon/article/details/81016222

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本文介绍了一个自定义的HTTPServletRequestWrapper类，该类继承自HttpServletRequestWrapper，主要用于解决ServletInputStream只能被读取一次的问题。通过缓存请求体的内容，使得可以在同一个请求中多次读取输入流。

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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.*;

/**
 * 封装Request，提供InputStream重复读取支持
 */
public class HTTPServletRequestWrapper extends HttpServletRequestWrapper {

    private final String body;

    public HTTPServletRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);

        StringBuilder stringBuilder = new StringBuilder();

        InputStream inputStream = request.getInputStream();

        if (inputStream != null) {

            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));

            char[] chunk = new char[128];

            int bytesRead;

            while ((bytesRead = bufferedReader.read(chunk)) > 0) {
                stringBuilder.append(chunk, 0, bytesRead);
            }

        } else {
            stringBuilder.append("");
        }

        body = stringBuilder.toString();

    }

    /**
     * 重新getInputStream，缓存Body数据
     *
     * @return
     * @throws IOException
     */
    @Override
    public ServletInputStream getInputStream() throws IOException {

        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());

        ServletInputStream servletInputStream = new ServletInputStream() {

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

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

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

            @Override
            public void setReadListener(ReadListener listener) {

            }

        };

        return servletInputStream;

    }

    /**
     * 读取缓存数据
     *
     * @return
     * @throws IOException
     */
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(this.getInputStream()));
    }

}