URL jsf2 中的参数 [英] parameter in URL jsf2

问题描述

我需要这个链接:

http://myserver:/myproject/innerpage/clip.jsf&id=9099

从这样的代码中提取id:

to extract the id from a code like this:

HttpServletRequest request = (HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest();
String clipId = request.getParameter("id");

当我在 tomcat 上运行它时，我得到:

When I run it on tomcat I get:

留言/OnAir/innerpage/clip.jsf&id=9099

message /OnAir/innerpage/clip.jsf&id=9099

description 请求的资源(/OnAir/innerpage/clip.jsf&id=9099)不可用.

description The requested resource (/OnAir/innerpage/clip.jsf&id=9099) is not available.

当我在没有 &id=9099 的情况下运行它时，它运行正常.

When I run it without &id=9099 it runs all right.

我怎样才能让它运行?

推荐答案

URL 中路径和查询字符串之间的分隔符是?，而不是&.& 是查询字符串中多个参数的分隔符，例如name1=value1&name2=value2&name3=value3.如果省略 ?，则查询字符串将被视为 URL 中路径的一部分，这将导致您遇到的 HTTP 404 页面/资源未找到错误.

The separator character between path and query string in URL is ?, not &. The & is separator character for multiple parameters in query string, e.g. name1=value1&name2=value2&name3=value3. If you omit the ?, then the query string will be seen as part of path in URL, which will lead to a HTTP 404 page/resource not found error as you encountered.

因此，此链接应该可以使用 http://myserver:port/myproject/innerpage/clip.jsf?id=9099

So, this link should work http://myserver:port/myproject/innerpage/clip.jsf?id=9099

也就是说，有一个更好的方法来访问请求参数.将其设置为值为 #{param.id} 的托管属性.

That said, there's a much better way to access the request parameter. Set it as a managed property with a value of #{param.id}.

public class Bean {

    @ManagedProperty(value="#{param.id}")
    private Long id;

    @PostConstruct
    public void init() {
        System.out.println(id); // 9099 as in your example.
    }

    // ...
}

EL #{param.id} 返回 request.getParameter("id") 的值.

The EL #{param.id} returns you the value of request.getParameter("id").

提示:每当您需要从托管 bean 内的 JSF 引擎盖下提取原始"Servlet API 时，请始终问自己(或在 SO):难道没有 JSF 风格的方法吗?".很有可能你把事情不必要地复杂化了 ;)

A tip: whenever you need to haul the "raw" Servlet API from under the JSF hoods inside a managed bean, always ask yourself (or here at SO): "Isn't there a JSF-ish way?". Big chance you're unnecessarily overcomplicating things ;)

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