Java中如何新建一个HttpServletRequest并复制当前线程HttpServletRequest的信息，而不是复制其引用

为了新建一个HttpServletRequest并复制当前线程HttpServletRequest的信息，我们可以使用ServletRequestWrapper类。ServletRequestWrapper类是HttpServletRequest的子类，它提供了一个构造函数，该构造函数接受一个HttpServletRequest对象作为参数，并将其存储在类的私有变量中。然后，我们可以覆盖ServletRequestWrapper类中的各种方法，以便在调用这些方法时使用存储的HttpServletRequest对象的信息。以下是一个示例代码：

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;

public class CustomHttpServletRequest extends HttpServletRequestWrapper {
    private final String body;

    public CustomHttpServletRequest(HttpServletRequest request) throws IOException {
        super(request);
        StringBuilder stringBuilder = new StringBuilder();
        InputStream inputStream = request.getInputStream();
        if (inputStream != null) {
            try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8))) {
                char[] charBuffer = new char[128];
                int bytesRead;
                while ((bytesRead = bufferedReader.read(charBuffer)) != -1) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            }
        }
        body = stringBuilder.toString();
    }

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

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

在上面的代码中，我们创建了一个名为CustomHttpServletRequest的类，它扩展了ServletRequestWrapper类。在CustomHttpServletRequest类的构造函数中，我们将传递的HttpServletRequest对象存储在类的私有变量中，并将请求体转换为字符串。然后，我们覆盖了getInputStream()和getReader()方法，以便在调用这些方法时使用存储的HttpServletRequest对象的信息。

要使用CustomHttpServletRequest类，我们只需在原始HttpServletRequest对象上调用它的构造函数即可。例如：

HttpServletRequest originalRequest = ...;
CustomHttpServletRequest customRequest = new CustomHttpServletRequest(originalRequest);