SpringRequestContext源码阅读

Spring源码关于RequestContext相关信息获取 事件监听器的相关代码实现

1public class RequestContextListener implements ServletRequestListener {
2    private static final String REQUEST_ATTRIBUTES_ATTRIBUTE = RequestContextListener.class
3            .getName() + ".REQUEST_ATTRIBUTES";
4
5    public void requestInitialized(ServletRequestEvent requestEvent) {
6        if (!(requestEvent.getServletRequest() instanceof HttpServletRequest)) {
7            throw new IllegalArgumentException(
8                    "Request is not an HttpServletRequest: "
9                            + requestEvent.getServletRequest());
10        }
11
12        HttpServletRequest request = (HttpServletRequest) requestEvent
13                .getServletRequest();
14        ServletRequestAttributes attributes = new ServletRequestAttributes(
15                request);
16        request.setAttribute(REQUEST_ATTRIBUTES_ATTRIBUTE, attributes);
17        LocaleContextHolder.setLocale(request.getLocale());
18        RequestContextHolder.setRequestAttributes(attributes);
19    }
20
21    public void requestDestroyed(ServletRequestEvent requestEvent) {
22        ServletRequestAttributes attributes = null;
23        Object reqAttr = requestEvent.getServletRequest().getAttribute(
24                REQUEST_ATTRIBUTES_ATTRIBUTE);
25        if (reqAttr instanceof ServletRequestAttributes) {
26            attributes = (ServletRequestAttributes) reqAttr;
27        }
28        RequestAttributes threadAttributes = RequestContextHolder
29                .getRequestAttributes();
30        if (threadAttributes != null) {
31            LocaleContextHolder.resetLocaleContext();
32            RequestContextHolder.resetRequestAttributes();
33            if ((attributes == null)
34                    && (threadAttributes instanceof ServletRequestAttributes)) {
35                attributes = (ServletRequestAttributes) threadAttributes;
36            }
37        }
38        if (attributes != null)
39            attributes.requestCompleted();
40    }
41}
42
43public abstract interface ServletRequestListener extends EventListener {
44    public abstract void requestDestroyed(
45            ServletRequestEvent paramServletRequestEvent);
46
47    public abstract void requestInitialized(
48            ServletRequestEvent paramServletRequestEvent);
49}
50
51public interface EventListener {
52}
53
54
55
56public class ServletRequestEvent extends EventObject {
57    private static final long serialVersionUID = 1L;
58    private final transient ServletRequest request;
59
60    public ServletRequestEvent(ServletContext sc, ServletRequest request) {
61        super(sc);
62        this.request = request;
63    }
64
65    public ServletRequest getServletRequest() {
66        return this.request;
67    }
68
69    public ServletContext getServletContext() {
70        return ((ServletContext) super.getSource());
71    }
72}
73
74
75
76public class EventObject implements java.io.Serializable {
77
78    private static final long serialVersionUID = 5516075349620653480L;
79
80    /**
81     * The object on which the Event initially occurred.
82     */
83    protected transient Object  source;
84
85    /**
86     * Constructs a prototypical Event.
87     *
88     * @param    source    The object on which the Event initially occurred.
89     * @exception  IllegalArgumentException  if source is null.
90     */
91    public EventObject(Object source) {
92        if (source == null)
93            throw new IllegalArgumentException("null source");
94
95        this.source = source;
96    }
97
98    /**
99     * The object on which the Event initially occurred.
100     *
101     * @return   The object on which the Event initially occurred.
102     */
103    public Object getSource() {
104        return source;
105    }
106
107    /**
108     * Returns a String representation of this EventObject.
109     *
110     * @return  A a String representation of this EventObject.
111     */
112    public String toString() {
113        return getClass().getName() + "[source=" + source + "]";
114    }
115}