责任链模式-- chainResponsibility

责任链模式在Struts中用的很多。

代码：

　　1. 创建两个基本类　　

package pr.cgl.chainResponsibility;

/**
 * Created by LL on 2015/8/27.
 */
public class Request {
   public String requestStr;

   public String getRequestStr() {
      return requestStr;
   }

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

package pr.cgl.chainResponsibility;

/**
 * Created by LL on 2015/8/27.
 */
public class Response {
   public String responseStr;

   public String getResponseStr() {
      return responseStr;
   }

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

2. 创建Filter接口

package pr.cgl.chainResponsibility;

/**
 * Created by LL on 2015/8/27.
 */
public interface Filter {
   void doFilter(Request request, Response response, FilterChain fc);
}
3. 创建Filter接口的实现类　　

package pr.cgl.chainResponsibility;

/**
 * Created by LL on 2015/8/27.
 */
public class HTMLFilter implements Filter {

   @Override
   public void doFilter(Request request, Response response, FilterChain fc) {
      request.requestStr += "--HTMLFilter";
      fc.doFilter(request, response, fc);
      response.responseStr += "--HTMLFilter";
   }
}

package pr.cgl.chainResponsibility;
/**
 * Created by LL on 2015/8/27.
 */
public class SensitiveFilter implements Filter {

   @Override
   public void doFilter(Request request, Response response, FilterChain fc) {
      request.requestStr += "--SensitiveFilter";
      fc.doFilter(request, response, fc);
      response.responseStr += "--SensitiveFilter";
   }
}

4. 创建过滤器链FilterChain

package pr.cgl.chainResponsibility;

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

/**
 * Created by LL on 2015/8/27.
 */
public class FilterChain implements Filter {

   List<Filter> filters = new ArrayList<Filter>();
   int i = 0;

   public List<Filter> getFilters() {
      return filters;
   }

   public void setFilters(List<Filter> filters) {
      this.filters = filters;
   }

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

   @Override
   public void doFilter(Request request, Response response, FilterChain fc) {
      if(i == filters.size()) return;
      Filter filter = filters.get(i);
      i++;
      filter.doFilter(request, response, fc);
   }
}
红色部分是责任链的关键。
5.测试
　　

package pr.cgl.chainResponsibility;

/**
 * Created by LL on 2015/8/27.
 */
public class Test1 {
   public static void main(String[] args) {
      Request request = new Request();
      request.setRequestStr("cgl and xf ");
      Response response = new Response();
      response.setResponseStr("xf and response");
      HTMLFilter htmlFilter = new HTMLFilter();
      SensitiveFilter sensitiveFilter = new SensitiveFilter();
      FilterChain fc = new FilterChain();
      fc.addFilter(htmlFilter).addFilter(sensitiveFilter);
      fc.doFilter(request, response, fc);
      System.out.println(request.getRequestStr());
      System.out.println(response.getResponseStr());
   }
}
输出：
　　cgl and xf --HTMLFilter--SensitiveFilter
　　xf and response--SensitiveFilter--HTMLFilter