java责任链模式

//过滤器接口: Filter
package com.bjsxt.chain;
 
public interface Filter {
    public void doFilter(Request request, Response response);
}
 
//实现类1 : Fillter1
package com.bjsxt.chain;
 
public class Filter1 implements Filter {
 
    public void doFilter(Request request, Response response) {
       String str = request.getRequestParameter();
       str += " pass filter1 ";
       request.setRequestParameter(str);
    }
 
}
 
//实现类2
package com.bjsxt.chain;
 
public class Filter2 implements Filter {
   
    public void doFilter(Request request, Response response) {
       String str = request.getRequestParameter();
       str += " pass filter2 ";
       request.setRequestParameter(str);
    }
 
}
 
//过滤链
import java.util.ArrayList;
import java.util.List;
public class Filterchain implements Filter {
   
    List<Filter> filters = new ArrayList<Filter>();
      
    public Filterchain addFilter(Filter filter) {
       filters.add(filter);
       return this;
    }
 
    public void doFilter(Request request, Response response) {
       for (Filter f : filters) {
           f.doFilter(request, response);
       }
    }
   
}
 
//模拟request
package com.bjsxt.chain;
 
public class Request {
   
    private String requestParameter = "";
 
    public String getRequestParameter() {
       return requestParameter;
    }
 
    public void setRequestParameter(String requestParameter) {
       this.requestParameter = requestParameter;
    }
 
}
 
//模拟response
package com.bjsxt.chain;
 
public class Response {
   
    private String responseParameter;
 
    public String getResponseParameter() {
       return responseParameter;
    }
 
    public void setResponseParameter(String responseParameter) {
       this.responseParameter = responseParameter;
    }
   
}
 
//测试主类
package com.bjsxt.chain;
 
public class MainClass {
 
    public static void main(String[] args) {
      
       Request request = new Request();
       Response response = new Response();
      
      
       Filterchain chain1 = new Filterchain();
       chain1.addFilter(new Filter1());
      
       Filterchain chain2 = new Filterchain();
       chain2.addFilter(new Filter2());
      
       chain1.addFilter(chain2);
      
       chain1.doFilter(request, response);
      
       System.out.println(request.getRequestParameter());
      
    }
 
}
 
//改进后的过滤器
 
//过滤器接口类
package com.bjsxt.chain;
 
public interface Filter {
    public void doFilter(Request request, Response response, FilterChain filterChain);
}
 
//过滤器实现类1
package com.bjsxt.chain;
 
public class Filter1 implements Filter {
 
    public void doFilter(Request request, Response response, FilterChain filterChain) {
       String str = request.getRequestParameter();
       str += "request pass filter1 ";
       request.setRequestParameter(str);
       filterChain.doFilter(request, response, filterChain);
       str = response.getResponseParameter();
       str += "response pass filter1";
       response.setResponseParameter(str);
    }
 
}
 
//过滤器实现类2
package com.bjsxt.chain;
 
public class Filter2 implements Filter {
   
    public void doFilter(Request request, Response response, FilterChain filterChain) {
       String str = request.getRequestParameter();
       str += "request pass filter2 ";
       request.setRequestParameter(str);
       filterChain.doFilter(request, response, filterChain);
      
       str = response.getResponseParameter();
       str += "response pass filter2";
       response.setResponseParameter(str);
    }
 
}
过滤器链
package com.bjsxt.chain;
 
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;
public class FilterChain implements Filter {
   
    List<Filter> filters = new ArrayList<Filter>();
      
    Stack<Filter> stack = new Stack<Filter>();
   
    private int i = 0;
    public FilterChain addFilter(Filter filter) {
       filters.add(filter);
       return this;
    }
 
    public void doFilter(Request request, Response response, FilterChain filterChain) {
       if (i == filters.size()) return;
       Filter filter = filters.get(i);
       i++;
       filter.doFilter(request, response, filterChain);
      
    }
   
}
 
 
//测试主类
 
package com.bjsxt.chain;
 
public class MainClass {
 
    public static void main(String[] args) {
      
       Request request = new Request();
       Response response = new Response();
      
       FilterChain chain1 = new FilterChain();
       chain1.addFilter(new Filter1())
              .addFilter(new Filter2());
      
       chain1.doFilter(request, response, chain1);
      
       System.out.println(request.getRequestParameter());
       System.out.println(response.getResponseParameter());
      
    }