带有servlet的jQuery自动完成UI不返回任何数据

Vij*_*Nil 3 javascript java jquery servlets jquery-autocomplete

我过去几个小时一直在摆弄这段代码片段,但我无法理解jQuery的自动完成UI是如何工作的.我按照本教程http://viralpatel.net/blogs/tutorial-create-autocomplete-feature-with-java-jsp-jquery/ 我使用了相同的示例,但我没有向JSP发送请求,而是使用了servlet.请求到达servlet"Fetcher",它也会执行,但没有任何内容返回到页面.这是代码.

public class Fetcher extends HttpServlet {
    [...]

    List<String> countryList = new ArrayList<String>();
    String param = request.getParameter("term");

    countryList.add("USA");
    countryList.add("Pakistan");
    countryList.add("Britain");
    countryList.add("India");
    countryList.add("Italy");
    countryList.add("Ireland");
    countryList.add("Bangladesh");
    countryList.add("Brazil");
    countryList.add("United Arab Emirates");
    PrintWriter out = response.getWriter();
    response.setContentType("text/plain");
    response.setHeader("Cache-Control", "no-cache");
     for(String country : countryList){
        out.println(country);
    }

    [...]
}
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HTML中的Javascript片段:

 <script>
       $(function() {

         $( "#tags" ).autocomplete({
          source: "Fetcher"

      });
 });
 </script>
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HTML表单:

 <label for="tags">Tags: </label>
 <input id="tags" />
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页面上的示例似乎是在jquery中为专业人士编写的, http://jqueryui.com/autocomplete/#default.请,有人可以告诉它究竟是如何工作的,以便我可以在其他地方使用它.

Ber*_*ium 11

servlet的应该返回自动完成数据作为JSON.有几个选项,我选择了一个包含带标签/值属性的对象的数组:

@WebServlet("/autocomplete/*")
public class AutoCompleteServlet extends HttpServlet {
    @Override
    protected void doPost(final HttpServletRequest request,
            final HttpServletResponse response) throws ServletException,
            IOException {

        final List<String> countryList = new ArrayList<String>();
        countryList.add("USA");
        countryList.add("Pakistan");
        countryList.add("Britain");
        countryList.add("India");
        countryList.add("Italy");
        countryList.add("Ireland");
        countryList.add("Bangladesh");
        countryList.add("Brazil");
        countryList.add("United Arab Emirates");
        Collections.sort(countryList);

        // Map real data into JSON

        response.setContentType("application/json");

        final String param = request.getParameter("term");
        final List<AutoCompleteData> result = new ArrayList<AutoCompleteData>();
        for (final String country : countryList) {
            if (country.toLowerCase().startsWith(param.toLowerCase())) {
                result.add(new AutoCompleteData(country, country));
            }
        }
        response.getWriter().write(new Gson().toJson(result));
    }
}
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要返回自动完成数据,您可以使用此帮助程序类:

class AutoCompleteData {
    private final String label;
    private final String value;

    public AutoCompleteData(String _label, String _value) {
        super();
        this.label = _label;
        this.value = _value;
    }

    public final String getLabel() {
        return this.label;
    }

    public final String getValue() {
        return this.value;
    }
}
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所以在servlet中,真实数据被映射成适合jQuery自动完成的形式.我选择了Google GSON将结果序列化为JSON.

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对于HTML文档(在.jsp中实现),选择正确的库,样式表和样式:

<html>
    <head>
        <script type="text/javascript" src="http://code.jquery.com/jquery-1.10.2.js"> </script>
        <script type="text/javascript" src="http://code.jquery.com/ui/1.10.3/jquery-ui.js"> </script>
        <link rel="stylesheet" href="http://code.jquery.com/ui/1.10.2/themes/smoothness/jquery-ui.css" />

        <script type="text/javascript" src="autoComplete.js"> </script>
    </head>

    <body>
        <form>
            <div class="ui-widget">
                <label for="country">Country: </label>
                <input id="country" />
            </div>
        </form>
    </body>
</html>
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相关:jQuery自动完成演示


我把Javascript函数放在一个单独的文件中autoComplete.js:

$(document).ready(function() {
    $(function() {
        $("#country").autocomplete({
            source: function(request, response) {
                $.ajax({
                    url: "/your_webapp_context_here/autocomplete/",
                    type: "POST",
                    data: { term: request.term },

                    dataType: "json",

                    success: function(data) {
                        response(data);
                    }
               });              
            }   
        });
    });
});
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自动完成功能使用AJAX请求来调用servlet.由于servlet的结果是合适的,因此可以按原样用于响应.

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