<!-- language: java-->
package bhatti;
public class find extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;");
PrintWriter out = response.getWriter();
out.println("<html><body>");
out.println("<feildset>");
out.println("<form action='display' method='get'>");
out.println("<tr>");
out.println("<td>ID :</td><td> <input type='text' name='id' style='width=70px;'></td><tr><br>");
out.println("<tr><td>Uints: </tr><tr><input type='text' name='uints' style='width=70px;' ></td></tr><br>");
out.println("<tr><td><input type='submit' value='submit' ></td></tr><br>");
out.println("</form>");
out.println("</feildset>");
out.println("</body></html>");
int i = Integer.parseInt(request.getParameter("id"));
int u = Integer.parseInt(request.getParameter("uints"));
float bill;
bill = (float)(u * (1.5));
float s;
s = (float)(bill * 0.05);
float totalbill;
totalbill = bill - s;
RequestDispatcher requestDispatcher = getServletContext().getRequestDispatcher("display.java");
requestDispatcher.forward(request, response);
request.setAttribute("id", i);
request.setAttribute("uints", u);
request.setAttribute("totalbill", totalbill);
}
}
second servlet
package bhatti;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class display extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;");
PrintWriter out = response.getWriter();
int i = Integer.parseInt(request.getParameter("id"));
int u = Integer.parseInt(request.getParameter("uints"));
float tb = Float.parseFloat(request.getParameter("totalbill"));
out.println("<p>ID: " + i + " </p><br>");
out.println("<p>Uints: " + u + "</p><br>");
out.println("<p>Subsidy: " + " 5%" + "</p><br>");
out.println("<h1>Total Bill:" + tb + "</h1><br>");
}
}
浮点值没有发送到另一个 servlet
错误是 HTTP 状态 500 -
输入异常报告
信息
说明 服务器遇到内部错误，无法完成此请求。
例外
java.lang.NullPointerException sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1838) sun.misc.FloatingDecimal.parseFloat(FloatingDecimal.java:122) java.lang.Float.parseFloat(Float.java:451) bhatti.display .doGet(display.java:26) javax.servlet.http.HttpServlet.service(HttpServlet.java:622) javax.servlet.http.HttpServlet.service(HttpServlet.java:729) org.apache.tomcat.websocket.server .WsFilter.doFilter(WsFilter.java:52) org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
注意 Apache Tomcat/8.0.27 日志中提供了根本原因的完整堆栈跟踪。
您正在一个 servlet 中设置属性，并尝试在另一个 servlet 中获取参数。
getParameter 无法获取setAttribute 值，但
只能通过 getAttribute 获取 setAttribute 值
所以从请求中使用 getAttribute 作为
request.getAttribute ("totalBill") ;
在你的情况下request.getParameter("totalBill")是 NULL 并且Float.parseFloat(null)会通过NullPointerException，因此你得到 HttpResponse 状态 500，即内部服务器错误。
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