字符过滤器（JavaWEBFilter）

package com.bjsxt.dp.filter;


public interface Filter {
void doFilter(Request request, Response response, FilterChain chain);

}

package com.bjsxt.dp.filter;


import java.util.ArrayList;
import java.util.List;


public class FilterChain implements Filter {
List<Filter> filters = new ArrayList<Filter>();
int index = 0;

public FilterChain addFilter(Filter f) {
this.filters.add(f);
return this;
}

@Override
public void doFilter(Request request, Response response, FilterChain chain) {
if(index == filters.size()) return ;

Filter f = filters.get(index);
index ++;
f.doFilter(request, response, chain);
}
}

package com.bjsxt.dp.filter;


public class HTMLFilter implements Filter {





@Override
public void doFilter(Request request, Response response, FilterChain chain) {
//process the html tag <>
request.requestStr = request.requestStr.replace('<', '[')
  .replace('>', ']') + "---HTMLFilter()";
chain.doFilter(request, response, chain);
response.responseStr += "---HTMLFilter()";
}


}

package com.bjsxt.dp.filter;


public class Main {


/**
* @param args
*/
public static void main(String[] args) {
String msg = "大家好:)，<script>，敏感，被就业，网络授课没感觉，因为看不见大家伙儿";
Request request = new Request();
request.setRequestStr(msg);
Response response = new Response();
response.setResponseStr("response");
FilterChain fc = new FilterChain();
fc.addFilter(new HTMLFilter())
 .addFilter(new SesitiveFilter())
 ;

fc.doFilter(request, response, fc);
System.out.println(request.getRequestStr());
System.out.println(response.getResponseStr());
}


}

package com.bjsxt.dp.filter;


public class Request {
String requestStr;


public String getRequestStr() {
return requestStr;
}


public void setRequestStr(String requestStr) {
this.requestStr = requestStr;
}
}

package com.bjsxt.dp.filter;


public class Response {
String responseStr;


public String getResponseStr() {
return responseStr;
}


public void setResponseStr(String responseStr) {
this.responseStr = responseStr;
}

}

package com.bjsxt.dp.filter;


public class SesitiveFilter implements Filter {





@Override
public void doFilter(Request request, Response response, FilterChain chain) {
request.requestStr = request.requestStr.replace("被就业", "就业")
.replace("敏感", "") + "---SesitiveFilter()";
chain.doFilter(request, response, chain);
response.responseStr += "---SesitiveFilter()";

}




}