只要做容器已经做的相同的工作。即在servlet过滤器所使用的覆盖范围内重新设计了chain of responsibility设计模式。
public class GodFilter implements Filter {
private Map<Pattern, Filter> filters = new LinkedHashMap<Pattern, Filter>();
@Override
public void init(FilterConfig config) throws ServletException {
Filter1 filter1 = new Filter1();
filter1.init(config);
filters.put(new Pattern("/foo/*"), filter1);
Filter2 filter2 = new Filter2();
filter2.init(config);
filters.put(new Pattern("*.bar"), filter2);
// ...
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
HttpServletRequest hsr = (HttpServletRequest) request;
String path = hsr.getRequestURI().substring(hsr.getContextPath().length());
GodFilterChain godChain = new GodFilterChain(chain);
for (Entry<Pattern, Filter> entry : filters.entrySet()) {
if (entry.getKey().matches(path)) {
godChain.addFilter(entry.getValue());
}
}
godChain.doFilter(request, response);
}
@Override
public void destroy() {
for (Filter filter : filters.values()) {
filter.destroy();
}
}
}
与那些小助手类(可以根据需要进行private static
嵌套类以上GodFilter
的):
public class Pattern {
private int position;
private String url;
public Pattern(String url) {
this.position = url.startsWith("*") ? 1
: url.endsWith("*") ? -1
: 0;
this.url = url.replaceAll("/?\\*", "");
}
public boolean matches(String path) {
return (position == -1) ? path.startsWith(url)
: (position == 1) ? path.endsWith(url)
: path.equals(url);
}
}
和
public class GodFilterChain implements FilterChain {
private FilterChain chain;
private List<Filter> filters = new ArrayList<Filter>();
private Iterator<Filter> iterator;
public GodFilterChain(FilterChain chain) {
this.chain = chain;
}
@Override
public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
if (iterator == null) {
iterator = filters.iterator();
}
if (iterator.hasNext()) {
iterator.next().doFilter(request, response, this);
} else {
chain.doFilter(request, response);
}
}
public void addFilter(Filter filter) {
if (iterator != null) {
throw new IllegalStateException();
}
filters.add(filter);
}
}
,你可以在必要时也喂带有所有可能的过滤器的XML配置文件,以便最终配置更简单。您可以使用反射在您的GodFilter
的init()
中创建滤镜。
哦没关系,那是什么web.xml
,并已经容器是做...
这将取决于servlet容器的,所以您在使用 – SJuan76
哪一个必须依赖你应该告诉我们什么? GuiceFilter是否依赖于容器? – TJR
Guice为自己的映射机制创建了一个类似于web.xml映射的映射机制 - 对于web容器,所有请求都以'GuiceFilter'结束。如果你想要Guice,只需使用它:) –