有人可以帮忙吗?我有下面的 servlet 类,每次我尝试从父类别中选择时,子类别中都不会显示任何内容。如果我做错了什么,请看看下面的内容。
谢谢
ajax部分:
$('#parentCategorySelector').change(function () {
var selectedValue = $(this).prop('value');
if (selectedValue == '--Select a parent category--') {
$('#categorySelector').empty();
} else {
$.post('${PREFIX}/category', selectedValue, function(data) {
var categorySelectorList = data.categorySelectorList;
$('#categorySelector').empty();
$.each(categorySelectorList, function(key, value) {
$('#categorySelector').append($('<option/>', {
value : value,
text : value
}));
});
}, 'json');
}
});
servlet 类:
public class CategoryServlet extends HttpServlet {
/**
* serialization
*/
private static final long serialVersionUID = -2461387206258395143L;
private static final Logger LOGGER = Logger
.getLogger(CategoryServlet.class);
private Connection connection = null;
int cat = 0;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
connection = DBConnection.getConnection();
RequestDispatcher dispatcher = request
.getRequestDispatcher("pages/all.jsp");
dispatcher.include(request, response);
String id = request.getParameter("id");
String category = request.getParameter("category");
String parentCategory = request.getParameter("parentCategory");
if (StringUtils.paramSet(id)) {
request.setAttribute("CATEGORY", CategoryService.getCategoryById(
Long.valueOf(id), connection));
} else if (StringUtils.paramSet(parentCategory)) {
request.setAttribute(
"CATEGORY",
CategoryService.getParentCategory(
Integer.valueOf(parentCategory), connection));
} else if (StringUtils.paramSet(category)) {
String categories = request.getParameter("category");
if (StringUtils.paramSet(categories)) {
request.setAttribute("CATEGORY",
CategoryService.listAllCategory(cat, connection));
}
dispatcher = request.getRequestDispatcher("jsp/pages/all.jsp");
} else {
request.setAttribute("CATEGORY",
CategoryService.listAllCategory(cat, connection));
}
dispatcher.include(request, response);
DBConnection.closeConnection(connection);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String action = request.getParameter("action");
LOGGER.info("TESTING " + action);
if (StringUtils.paramSet(action)) {
connection = DBConnection.getConnection();
Map<String, Object> resp = new HashMap<String, Object>();
// resp.put("error", "Please fill in all fields");
List<Category> categorySelectorList =
CategoryService.listAllCategory(cat,connection);
LOGGER.info("TESTING " + categorySelectorList);
// resp.put("categorySelectorList", categorySelectorList);
// LOGGER.info("TESTING 2 " + categorySelectorList);
try {
ResponseUtils.writeJson(resp, response);
} catch (Exception e) {
response.setContentType("application/json");
response.getWriter()
.write("{\"error\" : \"An error occured please try again. If the error persists, please refresh your browser \"}");
}
DBConnection.closeConnection(connection);
}
}
}
在jsp中看起来是这样的:
<div class="control-group">
<label class="control-label" for="selectError">Select
Category</label>
<div class="controls">
<select id="parentCategorySelector" name="parentCategorySelector"
data-rel="chosen">
<c:forEach items="${PARENTCATEGORY}" var="parentcategory">
<option value="${parentcategory.name}">
<c:out value="${parentcategory.name}" />
</option>
</c:forEach>
</select>
</div>
</div>
<div class="control-group">
<label class="control-label" for="selectError">Select
type</label>
<div class="controls">
<select id="categorySelector" name="categorySelector"
data-rel="chosen">
<c:forEach items="${CATEGORY}" var="subcategory">
<option value="${subcategory.category}">
<c:out value="${subcategory.category}" />
</option>
</c:forEach>
</select>
</div>
</div>
最佳答案
尝试改变这个:
var selectedValue = $(this).prop('value');
对此:
var selectedValue = this.value; //<---using navtive js code is better
和:
更改此:
$.post('${PREFIX}/category', selectedValue, function(data) {
对此:
$.post('${PREFIX}/category', {parentCategory:selectedValue}, function(data) {
由于您在请求参数中使用 'parentCategory'
,因此您必须按照建议将其传递到 $.post
函数中({ ParentCategory:selectedValue}
)。
关于java - 使用 servlet、jquery、ajax、json 进行链式选择,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21043873/