ThemeResolver (Spring Framework 5.2.12.RELEASE API)

所有已知实现类:
AbstractThemeResolver, CookieThemeResolver, FixedThemeResolver, SessionThemeResolver
```
public interface ThemeResolver
```
Interface for web-based theme resolution strategies that allows for both theme resolution via the request and theme modification via request and response.
This interface allows for implementations based on session, cookies, etc. The default implementation is FixedThemeResolver, simply using a configured default theme.
Note that this resolver is only responsible for determining the current theme name. The Theme instance for the resolved theme name gets looked up by DispatcherServlet via the respective ThemeSource, i.e. the current WebApplicationContext.
Use RequestContext.getTheme() to retrieve the current theme in controllers or views, independent of the actual resolution strategy.
从以下版本开始:
17.06.2003
作者:
Jean-Pierre Pawlak, Juergen Hoeller
另请参阅:
Theme, ThemeSource

方法概要

所有方法实例方法抽象方法
修饰符和类型	方法	说明
`String`	`resolveThemeName(HttpServletRequest request)`	Resolve the current theme name via the given request.
`void`	`setThemeName(HttpServletRequest request, HttpServletResponse response, String themeName)`	Set the current theme name to the given one.

- 方法详细资料
  - resolveThemeName
```
String resolveThemeName(HttpServletRequest request)
```
    Resolve the current theme name via the given request. Should return a default theme as fallback in any case.
    参数:
    request - the request to be used for resolution
    返回:
    the current theme name
  - setThemeName
```
void setThemeName(HttpServletRequest request,
                  @Nullable
                  HttpServletResponse response,
                  @Nullable
                  String themeName)
```
    Set the current theme name to the given one.
    参数:
    request - the request to be used for theme name modification
    response - the response to be used for theme name modification
    themeName - the new theme name (null or empty to reset it)
    抛出:
    UnsupportedOperationException - if the ThemeResolver implementation does not support dynamic changing of the theme