Question

我正在Eclipse中创建一个动态Web项目，无法弄清楚如何将查询结果发送到jsp文件。

这是servlet doGet：

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        HttpSession session = request.getSession();
        String name = session.getAttribute("user").toString();
        String query = "SELECT DISTINCT t.text, t.user, t.date"
                + " FROM users u, tweets t, follows f" 
                + " Where t.parent is null"
                + " AND u.id ='"+name + "'"
                + " AND ( f.follower = u.id"
                + " AND f.followed = t.user"
                + " OR t.user = u.id)"
                + " ORDER BY t.date DESC;";
        try {
            ResultSet rs = Dao.executeQuerySQL(query);
            while (rs.next()){
                //Get all tweets -> THIS IS THE INFO I WANT TO RETRIEVE 
                rs.getString(1);

            }

}

这是timeline.jsp：

<script>
$(document).ready(function(){


});
</script>
This is the timeline!

我如何在jsp中检索信息？

提前致谢。

Answer 1

对于doGet（）的Servlet部分

@WebServlet("/products")
public class ProductsServlet extends HttpServlet {

    @EJB
    private ProductService productService;

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<Product> products = productService.list();
        request.setAttribute("products", products); // Will be available as ${products} in JSP
        request.getRequestDispatcher("/WEB-INF/products.jsp").forward(request, response);
    }

}

对于JSP：

<table>
    <c:forEach items="${products}" var="product">
        <tr>
            <td>${product.name}</td>
            <td><a href="product?id=${product.id}">detail</a></td>
        </tr>
    </c:forEach>
</table>

资源链接：

doGet and doPost in Servlets

AJAX的UPDATE1：

将地图作为JSON

返回

这是另一个将Map<String, String>显示为<option>的示例：

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    Map<String, String> options = new LinkedHashMap<>();
    options.put("value1", "label1");
    options.put("value2", "label2");
    options.put("value3", "label3");
    String json = new Gson().toJson(options);

    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    response.getWriter().write(json);
}

和JSP：

$(document).on("click", "#somebutton", function() {               // When HTML DOM "click" event is invoked on element with ID "somebutton", execute the following function...
    $.get("someservlet", function(responseJson) {                 // Execute Ajax GET request on URL of "someservlet" and execute the following function with Ajax response JSON...
        var $select = $("#someselect");                           // Locate HTML DOM element with ID "someselect".
        $select.find("option").remove();                          // Find all child elements with tag name "option" and remove them (just to prevent duplicate options when button is pressed again).
        $.each(responseJson, function(key, value) {               // Iterate over the JSON object.
            $("<option>").val(key).text(value).appendTo($select); // Create HTML <option> element, set its value with currently iterated key and its text content with currently iterated item and finally append it to the <select>.
        });
    });
});

与

<select id="someselect"></select>

资源链接：

How to use Servlets and Ajax?

Answer 2

使用jaery ajax函数之一，如.ajax或.get来调用servlet。请参阅以下API链接。

http://api.jquery.com/jquery.ajax/

http://api.jquery.com/jquery.get/

这样的事，

$.get( "servlet url here", function( data ) {
  $( ".result" ).html( data );
  alert( "Load was performed." );
});

在servlet中将数据转换为json或html片段并写入响应。

在doGet方法和JSP页面之间进行通信的最佳方式是什么？

2 个答案:

对于JSP：

资源链接：

AJAX的UPDATE1：

将地图作为JSON

和JSP：

资源链接：