就是责任链模式思想了，包括Netty中的ChannelPipeline，也可以看成是一个链条容器，链条就是ChannelHandler了，
下面通过一个列子来演示责任链模式来展示其设计巧妙之处。
先定义一个接口Filter，即过滤器或者拦截器，里面有一个doFilter方法，用于过滤或拦截一些信息。
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packagecom.sf.simba.filter;
/**
*
* @author -simba-
*
*/
publicinterfaceFilter {
voiddoFilter(Request request,Response response,FilterChain filterChain);
}
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packagecom.sf.simba.filter;
/**
* @author -simba-
*
*/
publicclassHTMLFilterimplementsFilter {
@Override
publicvoiddoFilter(Request request, Response response,
FilterChain filterChain) {
request.setRequestStr(request.getRequestStr().replaceAll("<","[").replaceAll(">","]"));
System.out.println("------request:HTMLFilter-------");
filterChain.doFilter(request, response, filterChain);//执行下一个拦截器
response.setResponseStr(response.getResponseStr()+"------response:HTMLFilter------");//response返回
}
}
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权限校验类
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packagecom.sf.simba.filter;
/**
* 权限过滤器
* @author -simba-
*
*/
publicclassPowerFilterimplementsFilter {
@Override
publicvoiddoFilter(Request request, Response response,
FilterChain filterChain) {
request.setRequestStr(request.getRequestStr().replaceAll("权限","你有权限"));
System.out.println("------request:PowerFilter-------");
filterChain.doFilter(request, response, filterChain);
response.setResponseStr(response.getResponseStr()+"------response:PowerFilter------");
}
}
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敏感信息过滤类
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packagecom.sf.simba.filter;
/**
* 敏感过滤器
* @author -Simba-
*
*/
publicclassSensitiveFilterimplementsFilter {
@Override
publicvoiddoFilter(Request request, Response response,
FilterChain filterChain) {
request.setRequestStr(request.getRequestStr().replaceAll("饭桶在政府","高手在民间"));
System.out.println("------request:SensitiveFilter-------");
filterChain.doFilter(request, response, filterChain);
response.setResponseStr(response.getResponseStr()+"------response:SensitiveFilter------");
}
}
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请求类
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packagecom.sf.simba.filter;
/**
* 请求类
* @author -simba-
*
*/
publicclassRequest {
privateString requestStr;
publicString getRequestStr() {
returnrequestStr;
}
publicvoidsetRequestStr(String requestStr) {
this.requestStr = requestStr;
}
}
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返回类
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packagecom.sf.simba.filter;
publicclassResponse {
privateString responseStr;
publicString getResponseStr() {
returnresponseStr;
}
publicvoidsetResponseStr(String responseStr) {
this.responseStr = responseStr;
}
}
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过滤器处理类，处理每个链，其中它自己也是一个链，只是这个链中包含了几个小链条。
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packagecom.sf.simba.filter;
importjava.util.ArrayList;
importjava.util.List;
/**
* 拦截器链本身也是一种拦截器
* @author -simba-
*
*/
publicclassFilterChainimplementsFilter {
privateList<filter> filters =newArrayList<filter>();
private intindex =0;
publicFilterChain addFilter(Filter filter){
this.filters.add(filter);
returnthis;
}
@Override
publicvoiddoFilter(Request request, Response response,
FilterChain filterChain) {
if(index >= filters.size())return;
Filter filter = filters.get(index);
if(filterinstanceofFilterChain){//如果拦截器是一种拦截器链，那么需要把自己传入，即一个新的拦截器链
filter.doFilter(request, response, (FilterChain)filter);
}
index ++;
filter.doFilter(request, response, filterChain);//把拦截器链传个拦截器，好让拦截器知道下一个拦截器是谁
}
}</filter></filter>
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测试类
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packagecom.sf.simba.filter;
publicclassFilterMain {
publicstaticvoidmain(String[] args) {
String message ="你知道吗？饭桶在政府，<script>alert('权限')</script>,哈哈";
Request request =newRequest();
request.setRequestStr(message);
Response response =newResponse();
response.setResponseStr("response:");
FilterChain filterChain =newFilterChain();
filterChain.addFilter(newHTMLFilter())
.addFilter(newPowerFilter());
FilterChain filterChain1 =newFilterChain();
filterChain1.addFilter(newSensitiveFilter())
.addFilter(filterChain);
filterChain1.doFilter(request, response, filterChain1);
System.out.println(request.getRequestStr());
System.out.println(response.getResponseStr());
}
}
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测试结果
——request:SensitiveFilter——-
——request:HTMLFilter——-
——request:PowerFilter——-
你知道吗？高手在民间，[script]alert(‘你有权限’)[/script],哈哈
response:——response:PowerFilter————response:HTMLFilter————response:SensitiveFilter——
拦截器原理图如下：
