我想知道JSF中是否有拦截器(类似于Spring中使用的),以及如何实现它?
我想知道JSF中是否有拦截器(类似于Spring中使用的),以及如何实现它?
PhaseListener
实现此功能。您可以编程监听您在重写的getPhaseId()
方法中指定的特定JSF阶段。您可以通过beforePhase()
和afterPhase()
方法拦截前后阶段事件。public class RequestInterceptor implements PhaseListener {
@Override
public PhaseId getPhaseId() {
return PhaseId.RENDER_RESPONSE;
}
@Override
public void beforePhase(PhaseEvent event) {
// Do your job here which should run before the render response phase.
}
@Override
public void afterPhase(PhaseEvent event) {
// Do your job here which should run after the render response phase.
}
}
要让它运行,您需要在faces-config.xml
文件的<life-cycle>
部分中将其注册为<phase-listener>
。您可以拥有多个<phase-listener>
。
<lifecycle>
<phase-listener>com.example.RequestInterceptor</phase-listener>
</lifecycle>
在getPhaseId()
中可以指定PhaseId.ANY_PHASE
,以便让阶段监听器运行在每个JSF阶段上(请注意,并不一定会始终执行所有阶段,这取决于请求类型)。必要时,在阶段方法之前和之后可以通过PhaseEvent#getPhaseId()
获取当前阶段ID。
public class PhaseDebugger implements PhaseListener {
@Override
public PhaseId getPhaseId() {
return PhaseId.ANY_PHASE;
}
@Override
public void beforePhase(PhaseEvent event) {
System.out.println("Before phase " + event.getPhaseId());
}
@Override
public void afterPhase(PhaseEvent event) {
System.out.println("After phase " + event.getPhaseId());
}
}
或者,如果你想要一个更全局的钩子(因此不完全关注JSF请求/响应并且不需要从FacesContext获取任何内容),Filter
也应该同样好用。
@WebFilter("/*")
public class RequestInterceptor implements Filter {
@Override
public void init(FilterConfig config) {
// Initialize global variables if necessary.
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
// Do your job here which should run before the request processing.
chain.doFilter(request, response);
// Do your job here which should run after the request processing.
}
@Override
public void destroy() {
// Cleanup global variables if necessary.
}
}