動態填入下拉式清單

上次更新： 2023-11-07

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動態填入下拉式清單的程式

假設您想在某個案例中填入狀態下拉式清單的選取值國家下拉式清單。如果您在「」中選取「澳洲」國家下拉式清單，狀態下拉式清單會顯示澳洲境內的州。下列程式說明如何完成此工作。

建立包含下列模組的專案：
- 包含邏輯以填入下拉式清單（在此例中為servlet）的套件組合。
- 內嵌.jar檔案且具有下拉式資源的內容。此servlet指向此資源。

根據請求引數Country編寫servlet，該引數會傳回包含該國家/地區內州名的陣列。

@Component(metatype = false)
@Service(value = Servlet.class)
@Properties({
        @Property(name = "sling.servlet.resourceTypes", value = "/apps/populatedropdown"),
        @Property(name = "sling.servlet.methods", value = {"GET", "POST"}),
        @Property(name = "service.description", value = "Populate states dropdown based on country value")
})
public class DropDownPopulator extends SlingAllMethodsServlet {
    private Logger logger = LoggerFactory.getLogger(DropDownPopulator.class);

    protected void doPost(SlingHttpServletRequest request,
                          final SlingHttpServletResponse response)
            throws ServletException, IOException {
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setContentType("application/json");
        response.setCharacterEncoding("UTF-8");
        try {
            String US_STATES[] = {"0=Alabama",
                    "1=Alaska",
                    "2=Arizona",
                    "3=Arkansas",
                    "4=California",
                    "5=Colorado",
                    "6=Connecticut",
                    "7=Delaware",
                    "8=Florida",
                    "9=Georgia",
                    "10=Hawaii",
                    "11=Idaho",
                    "12=Illinois",
                    "13=Indiana",
                    "14=Iowa",
                    "15=Kansas",
                    "16=Kentucky",
                    "17=Louisiana",
                    "18=Maine",
                    "19=Maryland",
                    "20=Massachusetts",
                    "21=Michigan",
                    "22=Minnesota",
                    "23=Mississippi",
                    "24=Missouri",
                    "25=Montana",
                    "26=Nebraska",
                    "27=Nevada",
                    "28=New Hampshire",
                    "29=New Jersey",
                    "30=New Mexico",
                    "31=New York",
                    "32=North Carolina",
                    "33=North Dakota",
                    "34=Ohio",
                    "35=Oklahoma",
                    "36=Oregon",
                    "37=Pennsylvania",
                    "38=Rhode Island",
                    "39=South Carolina",
                    "40=South Dakota",
                    "41=Tennessee",
                    "42=Texas",
                    "43=Utah",
                    "44=Vermont",
                    "45=Virginia",
                    "46=Washington",
                    "47=West Virginia",
                    "48=Wisconsin",
                    "49=Wyoming"};
            String AUSTRALIAN_STATES[] = {"0=Ashmore and Cartier Islands",
                    "1=Australian Antarctic Territory",
                    "2=Australian Capital Territory",
                    "3=Christmas Island",
                    "4=Cocos (Keeling) Islands",
                    "5=Coral Sea Islands",
                    "6=Heard Island and McDonald Islands",
                    "7=Jervis Bay Territory",
                    "8=New South Wales",
                    "9=Norfolk Island",
                    "10=Northern Territory",
                    "11=Queensland",
                    "12=South Australia",
                    "13=Tasmania",
                    "14=Victoria",
                    "15=Western Australia"};
            String country = request.getParameter("country");
            JSONArray stateJsonArray = new JSONArray();
            if (country.length() > 0) {
                if ("australia".equalsIgnoreCase(country)) {
                    stateJsonArray = new JSONArray();
                    for (String state : AUSTRALIAN_STATES) {
                        stateJsonArray.put(state);
                    }
                } else if ("unitedstates".equalsIgnoreCase(country)) {
                    stateJsonArray = new JSONArray();
                    for (String state : US_STATES) {
                        stateJsonArray.put(state);
                    }
                }
                response.setContentType("application/json");
                response.getWriter().write(stateJsonArray.toString());
            }

        } catch ( Exception e) {
            logger.error(e.getMessage(), e);
        }
    }
}

在應用程式中的特定資料夾階層下建立下拉式節點（例如，在/apps/myfolder/demo下建立節點）。確保 sling:resourceType 節點的引數與servlet所指向的引數相同(/apps/populatedropdown?lang=zh-Hant)。
封裝內容節點並將.jar檔案內嵌於特定位置（例如/apps/myfolder/demo/install/）。在伺服器上部署相同的檔案。
建立最適化表單，並在其中新增兩個下拉式清單：國家/地區和州。國家/地區清單可包含國家/地區的名稱。「州」清單可動態填入您在第一個清單中所選國家/地區的州名。

新增要在國家/地區清單中顯示的國家/地區名稱。在「州」清單中，新增指令碼，以根據「國家/地區」清單中的國家/地區名稱填入指令碼。
```
JSON.parse(
    $.ajax({
        url: "/apps/myfolder/demo/dropdown",
        type: "POST",
        async: false,
        data: {"country": country.value},
         success: function(res){},
         error : function (message) {
              guideBridge._guide.logger().log(message);
              successFlag = false;
              }
           })
.responseText);
```