Filter设计模式，责任链模式一如既往的妙
场景1：
每种Filter进行某种处理，将各个Filter连在一起形成一个FilterChain。当需要往FilterChain中加入新的Filter，或者改变各个Filter的处理顺序时，可以方便的扩展。
1个接口：
public interface Filter {
public String dofilter(String msg);
}
3种实现类：
public class SensitiveWordFilter implements Filter{
@Override
public String dofilter(String msg) {
return msg.replace("fuck", "f**k").replace("Fuck", "F**k");
}
}
public class StopWordFilter implements Filter{
@Override
public String dofilter(String msg) {
return msg.replace("and", "").replace("to", "").replace("ing", "").replace("is", "");
}
}
public class FaceFilter implements Filter{
@Override
public String dofilter(String msg) {
return msg.replace(":(", "^V^");
}
}
用1个FilterChain连接起来：
public class FilterChain implements Filter{
List filters = new ArrayList();
@Override
public String dofilter(String msg) {
String r = msg;
for(Filter f : filters)
r = f.dofilter(r);
return r;
}
public FilterChain addFilter(Filter f){
filters.add(f);
return this;
}
}
main方法调用：
public class Main {
public static void main(String[] args){
String msg = "Today is raining. What a fucking day! :(";
FilterChain fc = new FilterChain();
fc.addFilter(new SensitiveWordFilter())
.addFilter(new StopWordFilter())
.addFilter(new FaceFilter());
String result = fc.dofilter(msg);
System.out.println(msg);
System.out.println(result);
}
}
场景2：
客户端==>服务端，参照javax.servlet
2种对象：
public class Request {
public String requestSTR;
}
public class Response {
public String responseSTR;
}
1个Filter接口：
public interface Filter {
public void dofilter(Request request,Response response, FilterChain fc);
}
3种实现类：
public class SensitiveWordFilter implements Filter{
@Override
public void dofilter(Request request, Response response, FilterChain fc) {
request.requestSTR = request.requestSTR.replace("fuck", "f**k").replace("Fuck", "F**k");
request.requestSTR += "--SensitiveWordFilter()";
fc.dofilter(request, response, fc);
response.responseSTR += "--SensitiveWordFilter()";
}
}
public class StopWordFilter implements Filter{
@Override
public void dofilter(Request request, Response response, FilterChain fc) {
request.requestSTR = request.requestSTR.replace("and", "").replace("to", "").replace("ing", "").replace("is", "");
request.requestSTR += "--StopWordFilter()";
fc.dofilter(request, response, fc);
response.responseSTR += "--StopWordFilter()";
}
}
public class FaceFilter implements Filter{
@Override
public void dofilter(Request request, Response response, FilterChain fc) {
request.requestSTR = request.requestSTR.replace(":(", "^V^");
request.requestSTR += "--FaceFilter()";
fc.dofilter(request, response, fc);
response.responseSTR += "--FaceFilter()";
}
}
FilterChain
public class FilterChain implements Filter{
List filters = new ArrayList();
int index = 0;
public FilterChain addFilter(Filter f){
filters.add(f);
return this;
}
@Override
public void dofilter(Request request, Response response, FilterChain fc) {
if(index == filters.size())
return;
Filter f = filters.get(index);
index++;
f.dofilter(request, response, this);
}
}
Main：
public class Main {
public static void main(String[] args){
Request request = new Request();
request.requestSTR = "Today is raining. What a fucking day! :(";
Response response = new Response();
response.responseSTR = "";
FilterChain fc = new FilterChain();
fc.addFilter(new SensitiveWordFilter())
.addFilter(new StopWordFilter())
.addFilter(new FaceFilter());
fc.dofilter(request,response,fc);
System.out.println(request.requestSTR);
System.out.println(response.responseSTR);
}
}