java - 如何使用 jSTL 从 url 获取一些值

Question

我有两个表单，action具有same-url，以下表单位于页面http://www.domain.com/pre- foo-url，即

<form:form commandName="some" class="form" action="/app/same-url">
    <form:input path="title"/>
    <input type="hidden" name="redirect" value="foo"/>
    <button>OK</button>
</form:form>

另一种形式位于http://www.domain.com/bar/{id}

 <form:form commandName="some" class="form" action="/app/same-url">
    <form:input path="tile"/>
    <input type="hidden" name="redirect" value="bar"/>
    <button>OK</button>
 </form:form>

我的 Controller 中有两种方法，一种用于决定重定向到

@RequestMapping(value = "/same-url", method = RequestMethod.POST)
public String handleRedirect(@RequestParam("redirect") String redirect) {
    if (redirect.equals("foo")) {               
        return "redirect:/foo";         
    } else {
        return "redirect:/bar/{id}"; // this {id} must get the value from http://www.domain.com/bar/{id}<-- Here
    }
} 

从 return "redirect:/bar/{id}"; 获取 id 值的其他方法并转到 /bar/{id} 请求映射

@RequestMapping(value = "/bar/{id}", method = RequestMethod.GET)
public String handleBar(@PathVariable Integer id) {
    // some logic here 
    return "go-any-where";
}

现在如何从 http://www.domain.com/bar/{id} 获取值并在将其重定向到 redirect:/bar/{id} 时进行设置},

Answer 1

我有一个适合您需求的解决方案，首先我必须指出您的需求，然后我会写下我的答案。

First:

-You need to get the /{id} from http://www.domain.com/bar/{id}, it means you want to get the value of last part of url.

您可以在页面http://www.domain.com/bar/{id}上添加以下代码来获取该值

<c:set var="currentPage" value="${requestScope['javax.servlet.forward.request_uri']}"/> <!--This will give you the path to current page eg- http://www.domain.com/bar/360 -->
<c:set var="splitURI" value="${fn:split(currentPage, '/')}"/> <!--This will split the path of current page -->
<c:set var="lastValue" value="${splitURI[fn:length(splitURI)-1]}"/><!--This will give you the last value of url "360" in this case -->
<c:out value="${lastValue}"></c:out> <!--use this to make sure you are getting correct value(for testing only) -->

Scond:

-You have to pass value of /{id} which is got from http://www.domain.com/bar/{id}.

使用 as 形式传递此内容。

<form:form commandName="some" class="form" action="/app/same-url">
   <form:input path="title"/>
   <input type="hidden" name="redirect" value="bar"/>
   <input type="hidden" name="path-var" value="${lastValue}"/>
   <button>OK</button>
<form:form>

At Last:

-You want to be redirected to redirect:/bar/{id}".

这可以使用下面的方法来完成。

@RequestMapping(value = "/add-category", method = RequestMethod.POST)
public String handleRedirect(@RequestParam("redirect") String redirect, @RequestParam("path-var") String pathVar) {
        if (redirect.equals("foo")) {               
            return "redirect:/foo";         
        } else {
            return "redirect:/bar/" + pathVar;  
        }
    } 

重要

This is not the Last/Best solution for the problem above.

这个问题可能还有其他/更好的解决方案。

Add this tag lib <%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn"%>, when using any jstl function just as fn:length().

希望这对您有用。