在对java servlet的ajax调用中，getParamteter不能处理文本元素

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

@WebServlet("/ajax")
public class AjaxServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        StringBuilder requestBody = new StringBuilder();
        BufferedReader reader = new BufferedReader(new InputStreamReader(request.getInputStream()));
        String line;
        while ((line = reader.readLine()) != null) {
            requestBody.append(line);
        }
        reader.close();

        // 处理文本元素
        String textElement = requestBody.toString();
        // 其他处理逻辑...

        // 返回响应
        response.setContentType("text/plain");
        response.getWriter().write("处理成功");
    }
}