Thymeleaf:将参数添加到当前网址

Question

我在

http://example.com/some/page?p1=11

我想在当前网址中添加一个参数,而不必重新定义它:

http://example.com/some/page?p1=11&p2=32

有类似的东西:

<a th:href="@{?(p2=32)}">Click here</a>

但上面的代码返回http://example.com/some/page?&p2=32(删除p1参数).

我怎么能用Thymeleaf做到这一点？

Answer 1

最简单的解决方案是连接"requestURI"和"queryString".这是一个例子:

<div th:with="currentUrl=(${#httpServletRequest.requestURI + '?' + #strings.defaultString(#httpServletRequest.queryString, '')})">
   <a th:href="@{${currentUrl}(myparam=test)}">click here</a>
</div>

" http:// localhost:8080/some-page？param1 = 1 "的结果:

 http://localhost:8080/some-page?param1=1&myparam=test

" http:// localhost:8080/some-page "的结果:

 http://localhost:8080/some-page?&myparam=test

缺点:
Thymeleaf不会覆盖参数 - 只会向URL添加参数.因此,如果用户再次单击该URL,结果将是:

http://localhost:8080/some-page?param1=1&myparam=test&myparam=test

参考文献:http:
//forum.thymeleaf.org/How-to-link-to-current-page-and-exchange-parameter-td4024870.html

编辑:

以下是一些解决方法,它从URL中删除参数"myparam":

<div th:with="currentUrl=(${@currentUrlWithoutParam.apply('myparam')})">
    <a th:href="@{${currentUrl}(myparam=test)}">click here</a>
</div>

接下来在Spring配置中:

@Bean
public Function<String, String> currentUrlWithoutParam() {
    return param ->   ServletUriComponentsBuilder.fromCurrentRequest().replaceQueryParam(param).toUriString();
}

对于更"全局"的解决方案,我会尝试为属性"th:href"扩展处理器或创建自己的属性.我不是一个百里香专家,只是面临类似的问题.

Answer 2

您可以直接从Thymeleaf使用URI构建器.

<span th:with="urlBuilder=${T(org.springframework.web.servlet.support.ServletUriComponentsBuilder).fromCurrentRequest()}"
      th:text="${urlBuilder.replaceQueryParam('p2', '32').toUriString()}">
</span>

对于URL http://example.com/some/page?p1=11打印输出:

http://example.com/some/page?p1=11&p2=32

解释:

• SpEL T运算符用于访问ServletUriComponentsBuilder类型.
• 由工厂方法创建的实例fromCurrentRequest保存到urlBuilder变量.
• 通过replaceQueryParam方法在查询字符串中添加或替换参数,然后构建URL.

优点:

• 安全解决方案
• ?在空查询字符串的情况下没有尾随.
• 在Spring上下文中没有额外的bean.

缺点:

• 这很冗长.

!请注意,上面的解决方案会创建一个构建器实例.这意味着构建器无法重用,因为它仍然会修改单个URL.对于页面上的多个URL,您必须创建多个构建器,如下所示:

<span th:with="urlBuilder=${T(org.springframework.web.servlet.support.ServletUriComponentsBuilder)}">
    <span th:text="${urlBuilder.fromCurrentRequest().replaceQueryParam('p2', 'whatever').toUriString()}"></span>
    <span th:text="${urlBuilder.fromCurrentRequest().replaceQueryParam('p3', 'whatever').toUriString()}"></span>
    <span th:text="${urlBuilder.fromCurrentRequest().replaceQueryParam('p4', 'whatever').toUriString()}"></span>
</span>

对于http://example.com/some/page打印:

http://example.com/some/page?p2=whatever 
http://example.com/some/page?p3=whatever     
http://example.com/some/page?p4=whatever