Get Root/Base Url In Spring MVC

问题

What is the best way to get the root/base url of a web application in Spring MVC?

Base Url = http://www.example.com or http://www.example.com/VirtualDirectory

回答1:

If base url is "http://www.example.com", then use the following to get the "www.example.com" part, without the "http://":

From a Controller:

@RequestMapping(value = "/someURL", method = RequestMethod.GET)
public ModelAndView doSomething(HttpServletRequest request) throws IOException{
    //Try this:
    request.getLocalName(); 
    // or this
    request.getLocalAddr();
}

From JSP:

Declare this on top of your document:

<c:set var="baseURL" value="${pageContext.request.localName}"/> //or ".localAddr"

Then, to use it, reference the variable:

<a href="http://${baseURL}">Go Home</a>

回答2:

You can also create your own method to get it:

public String getURLBase(HttpServletRequest request) throws MalformedURLException {

    URL requestURL = new URL(request.getRequestURL().toString());
    String port = requestURL.getPort() == -1 ? "" : ":" + requestURL.getPort();
    return requestURL.getProtocol() + "://" + requestURL.getHost() + port;

}

回答3:

I prefer to use

final String baseUrl = ServletUriComponentsBuilder.fromCurrentContextPath().build().toUriString();

It returns a completely built URL, scheme, server name and server port, rather than concatenating and replacing strings which is error prone.

回答4:

request.getRequestURL().toString().replace(request.getRequestURI(), request.getContextPath())

回答5:

In controller, use HttpServletRequest.getContextPath().

In JSP use Spring's tag library: or jstl

回答6:

Either inject a UriCompoenentsBuilder:

@RequestMapping(yaddie yadda)
public void doit(UriComponentBuilder b) {
  //b is pre-populated with context URI here
}

. Or make it yourself (similar to Salims answer):

// Get full URL (http://user:pwd@www.example.com/root/some?k=v#hey)
URI requestUri = new URI(req.getRequestURL().toString());
// and strip last parts (http://user:pwd@www.example.com/root)
URI contextUri = new URI(requestUri.getScheme(), 
                         requestUri.getAuthority(), 
                         req.getContextPath(), 
                         null, 
                         null);

You can then use UriComponentsBuilder from that URI:

// http://user:pwd@www.example.com/root/some/other/14
URI complete = UriComponentsBuilder.fromUri(contextUri)
                                   .path("/some/other/{id}")
                                   .buildAndExpand(14)
                                   .toUri();

回答7:

Simply :

String getBaseUrl(HttpServletRequest req) {
    return req.getScheme() + "://" + req.getServerName() + ":" + req.getServerPort() + req.getContextPath();
}

回答8:

Explanation

I know this question is quite old but it's the only one I found about this topic, so I'd like to share my approach for future visitors.

If you want to get the base URL from a WebRequest you can do the following:

ServletUriComponentsBuilder.fromRequestUri(HttpServletRequest request);

This will give you the scheme ("http" or "https"), host ("example.com"), port ("8080") and the path ("/some/path"), while fromRequest(request) would give you the query parameters as well. But as we want to get the base URL only (scheme, host, port) we don't need the query params.

Now you can just delete the path with the following line:

ServletUriComponentsBuilder.fromRequestUri(HttpServletRequest request).replacePath(null);

TLDR

Finally our one-liner to get the base URL would look like this:

//request URL: "http://example.com:8080/some/path?someParam=42"

String baseUrl = ServletUriComponentsBuilder.fromRequestUri(HttpServletRequest request)
        .replacePath(null)
        .build()
        .toUriString();

//baseUrl: "http://example.com:8080"

Addition

If you want to use this outside a controller or somewhere, where you don't have the HttpServletRequest present, you can just replace

ServletUriComponentsBuilder.fromRequestUri(HttpServletRequest request).replacePath(null)

with

ServletUriComponentsBuilder.fromCurrentContextPath()

This will obtain the HttpServletRequest through spring's RequestContextHolder. You also won't need the replacePath(null) as it's already only the scheme, host and port.

回答9:

     @RequestMapping(value="/myMapping",method = RequestMethod.POST)
      public ModelandView myAction(HttpServletRequest request){

       //then follow this answer to get your Root url
     }

Root URl of the servlet

If you need it in jsp then get in in controller and add it as object in ModelAndView.

Alternatively, if you need it in client side use javascript to retrieve it: http://www.gotknowhow.com/articles/how-to-get-the-base-url-with-javascript

回答10:

In JSP

<c:set var="scheme" value="${pageContext.request.scheme}"/>
<c:set var="serverPort" value="${pageContext.request.serverPort}"/>
<c:set var="port" value=":${serverPort}"/>

<a href="${scheme}://${pageContext.request.serverName}${port}">base url</a>

reference https://github.com/spring-projects/greenhouse/blob/master/src/main/webapp/WEB-INF/tags/urls/absoluteUrl.tag

回答11:

I think the answer to this question: Finding your application's URL with only a ServletContext shows why you should use relative url's instead, unless you have a very specific reason for wanting the root url.

来源：https://stackoverflow.com/questions/5012525/get-root-base-url-in-spring-mvc

标签

spring-mvc

base-url