在我的基于Java，带有BootStrap的JSP和Servlet上构建的应用程序中，存在将数据从Servlet发送到BootStrap Modal的问题。
基于我的项目，用户单击每个表容器中的“检查按钮”，并且table_id被javascript捕获，并使用该值将其发送到Servlet。然后，Servlet根据其table_id从数据库中获取数据。发送到BootStrap模态部分所需的操作的结果（代码中的顺序和结果在打印时会正确显示）。
TableMonitor.jsp
<%@ page language="java" contentType="text/html; charset=EUC-KR"
pageEncoding="EUC-KR"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport"
content="width=device-width, initial-scale=1, shrink-to-fit=no">
<meta name="description" content="">
<meta name="author" content="">
<link rel="icon" href="/docs/4.0/assets/img/favicons/favicon.ico">
<title>Migarock Table Monitoring System</title>
<link rel="canonical"
href="https://getbootstrap.com/docs/4.0/examples/pricing/">
<!-- Bootstrap core CSS -->
<link href="../../dist/css/bootstrap.min.css" rel="stylesheet">
<!-- Custom styles for this template -->
<link href="pricing.css" rel="stylesheet">
<link rel="stylesheet"
href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css"
integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T"
crossorigin="anonymous">
<link href="./css/tableMonitor.css" rel="stylesheet">
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
</head>
<body>
<!--
<div class="d-flex flex-column flex-md-row align-items-center p-3 px-md-4 mb-3 bg-white border-bottom box-shadow">
<h3 class="my-0 mr-md-auto font-weight-normal">Migarock Table Monitoring System</h3>
<a class="btn btn-outline-primary" href="#">Lock</a>
</div> -->
<div class="row">
<div class="col-2">
<div class="container">
<div class="card-deck mb-3 text-center ">
<div class="card mb-4 box-shadow ">
<div class="card-header status1">
<h3 class="my-0 font-weight-normal ">
<strong>Table_01</strong>
</h3>
</div>
<div class="card-body">
<a class="btn btn-outline-primary btn-lg btn-block mx-1 mt-1"
data-toggle="modal" href="#tableModal" data-table-id="1">Check</a>
</div>
</div>
</div>
</div>
</div>
<div class="col-2">
<div class="container">
<div class="card-deck mb-3 text-center">
<div class="card mb-4 box-shadow">
<div class="card-header">
<h3 class="my-0 font-weight-normal">
<strong>Table_02</strong>
</h3>
</div>
<div class="card-body">
<a class="btn btn-outline-primary btn-lg btn-block mx-1 mt-1"
data-toggle="modal" href="#tableModal" data-table-id="2">Check</a>
</div>
</div>
</div>
</div>
</div>
<div class="col-2">
<div class="container">
<div class="card-deck mb-3 text-center">
<div class="card mb-4 box-shadow">
<div class="card-header status2">
<h3 class="my-0 font-weight-normal">
<strong>Table_03</strong>
</h3>
</div>
<div class="card-body">
<a class="btn btn-outline-primary btn-lg btn-block mx-1 mt-1"
data-toggle="modal" href="#tableModal" data-table-id="3">Check</a>
</div>
</div>
</div>
</div>
</div>
<div class="col-2">
<div class="container">
<div class="card-deck mb-3 text-center">
<div class="card mb-4 box-shadow">
<div class="card-header">
<h3 class="my-0 font-weight-normal">
<strong>Table_04</strong>
</h3>
</div>
<div class="card-body">
<a class="btn btn-outline-primary btn-lg btn-block mx-1 mt-1"
data-toggle="modal" href="#tableModal" data-table-id="4">Check</a>
</div>
</div>
</div>
</div>
</div>
<div class="col-2">
<div class="container">
<div class="card-deck mb-3 text-center">
<div class="card mb-4 box-shadow">
<div class="card-header">
<h3 class="my-0 font-weight-normal">
<strong>Table_05</strong>
</h3>
</div>
<div class="card-body">
<a class="btn btn-outline-primary btn-lg btn-block mx-1 mt-1"
data-toggle="modal" href="#tableModal" data-table-id="5">Check</a>
</div>
</div>
</div>
</div>
</div>
<div class="col-2">
<div class="container">
<div class="card-deck mb-3 text-center">
<div class="card mb-4 box-shadow ">
<div class="card-header status3">
<h3 class="my-0 font-weight-normal">
<strong>Table_06</strong>
</h3>
</div>
<div class="card-body">
<a class="btn btn-outline-primary btn-lg btn-block mx-1 mt-1"
data-toggle="modal" href="#tableModal" data-table-id="6">Check</a>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="modal fade" id="tableModal" tabindex="1" role="dialog"
aria-labelledby="modal" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<h2 class="modal-title" id="modal">Table Status</h2>
<button type="button" class="close" data-dismiss="modal"
aria-label="close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="controlBar">
<div class="row">
<div class="col-8" style="text-align: left;">
<button type="button" class="btn btn-outline-success btn-lg"
data-dismiss="modal">Add item</button>
<button type="button" class="btn btn-outline-secondary btn-lg"
data-dismiss="modal">Change Status</button>
</div>
<div class="col-4" style="text-align: right; padding-right: 10%;">
<button type="button" class="btn btn-outline-warning btn-lg"
data-dismiss="modal">Help</button>
<button type="button" class="btn btn-outline-info btn-lg"
data-dismiss="modal">Bill</button>
</div>
</div>
<div>
<div class="modal-body">
<h3>My name is ${test}</h3>
<!-- <form action="./evaluationRegisterAction.jsp" method="post"> -->
<div class="scrollbar scrollbar-primary">
<!-- <div> -->
<table class="table">
<thead>
<tr style="text-align: center;">
<th scope="col"><input type="checkbox"
class="select-all checkbox" name="select-all" /></th>
<th scope="col">OrderTime</th>
<th scope="col">Item</th>
<th scope="col">QTY</th>
<th scope="col">Price</th>
<th scope="col">Status</th>
</tr>
</thead>
<tbody>
<c:out value="${requestScope.orders}">
<c:forEach items="${orders}" var="order">
<tr style="text-align: center;">
<td style="text-align: center;">
<div class="form-check">
<input type="checkbox" class="select-item checkbox"
name="select-item">
</div>
</td>
<td><span id="orders"></span> ${order.getTimeStamp()}</td>
<td>{order.getOrderItem()}</td>
<td>{order.getOrderQty()}</td>
<td>{order.getOrderPrice()}</td>
<td>{order.getOrderStatus()}</td>
<td><a class="btn btn-light btn-sm mx-1 mt-2"
data-toggle="modal" href="#changeStatus">Ordered</a> <!-- <a class="btn btn-dark btn-sm mx-1 mt-2" data-toggle="modal"
href="#changeStatus">Delivered</a> -->
</td>
</tr>
</c:forEach>
</c:out>
</tbody>
</table>
</div>
</div>
<div>
<table class="table">
<tr style="text-align: center;">
<td colspan="3">
<h4>Total</h4>
</td>
<td colspan="3">
<h4>(total)</h4>
</td>
</tr>
</table>
</div>
<div class="controlBar">
<div class="row">
<div class="col-6" style="text-align: left;">
<button type="button" class="btn btn-danger btn-lg"
data-dismiss="modal">Close Session</button>
</div>
<div class="col-6"
style="text-align: right; padding-right: 10%;">
<button type="button" class="btn btn-outline-danger btn-lg"
data-dismiss="modal">Close Window</button>
</div>
</div>
</div>
</div>
<!-- </form> -->
</div>
</div>
</div>
</div>
<footer class="pt-4 my-md-5 pt-md-5 border-top"> </footer>
</div>
<!-- Bootstrap core JavaScript
================================================== -->
<!-- Placed at the end of the document so the pages load faster -->
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js"
integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN"
crossorigin="anonymous"></script>
<script>
window.jQuery
|| document
.write('<script src="../../assets/js/vendor/jquery-slim.min.js"><\/script>')
</script>
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo"
crossorigin="anonymous"></script>
<script
src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"
integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1"
crossorigin="anonymous"></script>
<script
src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"
integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM"
crossorigin="anonymous"></script>
<script>
Holder.addTheme('thumb', {
bg : '#55595c',
fg : '#eceeef',
text : 'Thumbnail'
});
</script>
<script>
$(function() {
//button select all or cancel
$("#select-all").click(function() {
var all = $("input.select-all")[0];
all.checked = !all.checked
var checked = all.checked;
$("input.select-item").each(function(index, item) {
item.checked = checked;
});
});
//button select invert
$("#select-invert").click(function() {
$("input.select-item").each(function(index, item) {
item.checked = !item.checked;
});
checkSelected();
});
//button get selected info
$("#selected").click(
function() {
var items = [];
$("input.select-item:checked:checked").each(
function(index, item) {
items[index] = item.value;
});
if (items.length < 1) {
alert("no selected items!!!");
} else {
var values = items.join(',');
console.log(values);
var html = $("<div></div>");
html.html("selected:" + values);
html.appendTo("body");
}
});
//column checkbox select all or cancel
$("input.select-all").click(function() {
var checked = this.checked;
$("input.select-item").each(function(index, item) {
item.checked = checked;
});
});
//check selected items
$("input.select-item").click(function() {
var checked = this.checked;
console.log(checked);
checkSelected();
});
//check is all selected
function checkSelected() {
var all = $("input.select-all")[0];
var total = $("input.select-item").length;
var len = $("input.select-item:checked:checked").length;
console.log("total:" + total);
console.log("len:" + len);
all.checked = len === total;
}
});
$('#tableModal')
.on(
'show.bs.modal',
function(e) {
var tableID = $(e.relatedTarget).data('table-id');
console.log("test: ", tableID)
$(e.currentTarget).find('input[name="tableID"]')
.val(tableID);
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
// Typical action to be performed when the document is ready:
document.getElementById("response").value = xhttp.responseText;
}
};
xhttp.open("POST", "TableMonitor", true);
xhttp.setRequestHeader("Content-type",
"application/x-www-form-urlencoded");
xhttp.send("tableId=" + tableID);
var orders = $(this).data('orders');
$('#orders').html(orders);
});
</script>
</body>
</html>
TableMonitor.java（Servlet）
package servlets;
import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.servlet.RequestDispatcher;
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 brokers.TableBrokder;
import model.Order;
/**
* Servlet implementation class TableMonitor
*/
@WebServlet("/TableMonitor")
public class TableMonitor extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public TableMonitor() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
getServletContext().getRequestDispatcher("/TableMonitor.jsp").forward(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String table_id = request.getParameter("tableId");
String action = request.getParameter("action");
System.out.println("servlet: " + table_id);
List<Order> orders = null;
TableBrokder tb = new TableBrokder();
try {
orders = tb.getOrderAll(Integer.parseInt(table_id));
} catch (NumberFormatException | SQLException e) {
e.printStackTrace();
}
for (int i = 0; i < orders.size(); i++) {
orders.get(i).toString();
}
// response.sendRedirect("TableMonitor");
RequestDispatcher dispatcher = request.getRequestDispatcher("/TableMonitor.jsp");
request.setAttribute("orders", orders);
request.setAttribute("test", "test");
dispatcher.forward(request, response);
}
}
尽管我用谷歌搜索，但没有得到明确的答案。您能帮我解决这个问题吗？
好像您在js中进行ajax调用，但是在servlet中，您没有返回响应。我强烈建议您查看this answer如何使用servlet进行Ajax调用。
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String table_id = request.getParameter("tableId");
String action = request.getParameter("action");
System.out.println("servlet: " + table_id);
List<Order> orders = null;
TableBrokder tb = new TableBrokder();
try {
orders = tb.getOrderAll(Integer.parseInt(table_id));
} catch (NumberFormatException | SQLException e) {
e.printStackTrace();
}
for (int i = 0; i < orders.size(); i++) {
orders.get(i).toString();
}
//convert your list of orders to json
String json = new Gson().toJson(orders);
//add json to response
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
response.getWriter().write(json);
}
当您拨打ajax电话时，您将无法执行以下操作：
request.setAttribute("orders", orders);
request.setAttribute("test", "test");
因为当您通过ajax调用此servlet URL时，您不会再次加载jsp页面，因此HttpServletRequest不会传递到jsp页面。希望这有助于更多地了解它。