模拟javaWeb责任链的设计

这篇文章介绍了责任链模式的应用:本文介绍如果自己实现一个责任链

定义请求和响应信息

简单定义请求类Request(封装一个字符串)

public class Request {

    String requestStr;

    public String getRequestStr() {

        return requestStr;

    }

    public void setRequestStr(String requestStr) {

        this.requestStr = requestStr;

    }

}

简单定义响应类Response

public class Response {

    String responseStr;

    public String getResponseStr() {

        return responseStr;

    }

    public void setResponseStr(String responseStr) {

        this.responseStr = responseStr;

    }

}

定义Filter(参数接收Request和Response)

至于为什么接收FilterChain(是为了下面filter里面能够调用FilterChain的doFilter()方法)

定义Filter接口

把Request对象和Response对象交给处理器Filter:处理器既能处理Request对象也能处理Response对象

public interface Filter {

    void doFilter(Request request, Response response, FilterChain chain);

}

定义两个Filter实现类

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()";

    }

}

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()";

    }

}

定义FilterChain

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);

    }

}

main()方法测试

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());

    }

}

以上代码特点是 Request的处理是正序 Response的处理时倒序:

方便大家看清步骤:这是断点执行顺序

Filter里面调用了filterChain的doFilter方法

FilterChain里面调用了filter的doFilter方法

巴特西