设计模式之责任链模式（Chain of Responsibility）是Web项目中最经常用到的一个设计模式，比如是Apache Tomcat 的对Encoding的 处理，Struts2 的拦截器， jsp servlet 的Filter 等等，都是基于责任链模式设计的。
?
下面直接来模拟WEB发送一个请求Request经过两个过滤链HTMLFilter过滤标签、SensitiveFilter过滤敏感词汇，经过过滤之后返回一个Response对象
?
实例代码：
class="java" name="code">public interface Filter {
public void doFilter(Request req, Response rsp, FilterChain chain);
}
public class HTMLFilter implements Filter {
@Override
public void doFilter(Request req, Response rsp, FilterChain f) {
req.request = req.request.replace("<html>", "[html]")
+ "---HTMLFilter()";
f.doFilter(req, rsp, f);
rsp.response += "---HTMLFilter()";
}
}
public class SensitiveFilter implements Filter {
@Override
public void doFilter(Request req, Response rsp, FilterChain f) {
req.request = req.request.replace("很黄很暴力", "很xxx很xxx")
+ "---SensitiveFilter()";
f.doFilter(req, rsp, f);
rsp.response += "---SensitiveFilter()";
}
}
public class FilterChain implements Filter {
private List<Filter> list = new ArrayList<Filter>();
private int index;
@Override
public void doFilter(Request req, Response rsp, FilterChain chain) {
if (index == list.size()) {
return;
}
Filter f = list.get(index);
index++;
f.doFilter(req, rsp, chain);
}
public FilterChain addFilter(Filter f) {
list.add(f);
return this;
}
}
public class Request {
String request = "";
public String getRequest() {
return request;
}
public void setRequest(String request) {
this.request = request;
}
}
public class Response {
String response = "";
public String getResponse() {
return response;
}
public void setResponse(String response) {
this.response = response;
}
}
public class Main {
public static void main(String[] args) {
String msg = "<html>很黄很暴力,天天开心";
Request request = new Request();
request.setRequest(msg);
Response response = new Response();
// FilterChain ch = new FilterChain();
// ch.addFilter(new HTMLFilter()).addFilter(new SensitiveFilter());
FilterChain ch = new FilterChain();
ch.addFilter(new HTMLFilter());
FilterChain ch2 = new FilterChain();
ch2.addFilter(new SensitiveFilter());
ch.addFilter(ch2);// 过滤链上加过滤链
ch.doFilter(request, response, ch);
System.out.println(request.getRequest());
System.out.println(response.getResponse());
}
}
?
相关文章
