设计模式---责任链

r囧r小猫 2022-10-02 10:53 134阅读 0赞

运用责任链模式的例子：Tomcat过滤器、struts2的拦截器

理解：对特定对象进行过滤处理，屏蔽掉不合规则的东西。

事里问题：网页提交了一段字符串request，里面包含了敏感东西，把其中不合法的字段替换为合法的，返回一个字符串response，处理不合法的对象性。

关键解决问题：如何实现寻找下一个Filter处理过程，解决为List<Filter>处理

代码：

//主程序

package Filter;
    public class Main {
    /**
    * @param args
    */
    public static void main(String[] args) {
    String s = "大家好 :, <script>, 敏感, 被就业, 网络授课没感觉, 因为看不见大家伙";
    Request re = new Request();
    re.setRequeststr(s);
    Responce rp = new Responce();
    rp.setResponcestr("responce");
    Filterchain fc = new Filterchain();
    fc.addFilter(new HtmlFilter()).addFilter(new SensitiveFilter()).addFilter(new FaceFilter());
    fc.doFilter(re, rp,fc);
    System.out.println(re.getRequeststr());
    System.out.println(rp.getResponcestr());
    }
    }

//实现增加Filter和使用Filter处理的链条

package Filter;
    import java.util.ArrayList;
    import java.util.List;
    public class Filterchain implements Filter{
    private int index = 0;
    List<Filter> filters = new ArrayList<Filter>();
    public Filterchain addFilter(Filter f) {
    filters.add(f);
    return this;
    }
    @Override
    public void doFilter(Request request, Responce responce, Filterchain chain) {
    if(index == filters.size()) {
    return ;
    }
    Filter f = filters.get(index);
    index++;
    f.doFilter(request, responce,chain);
    }
    }

//Filter接口

package Filter;
    public interface Filter {
    public void doFilter(Request request, Responce responce, Filterchain chain);
    }

//实现Filter接口的类

package Filter;
    public  class FaceFilter implements Filter {
    @Override
    public void doFilter(Request request, Responce responce, Filterchain chain) {
    request.setRequeststr(request.getRequeststr().replace(":", "^v^") + "---FaceFilter");
    chain.doFilter(request, responce,chain);
    responce.setResponcestr(responce.getResponcestr() + "---FaceFilter");
    }
    }
    package Filter;
    public class HtmlFilter implements Filter {
    @Override
    public void doFilter(Request request, Responce responce,Filterchain chain) {
    request.setRequeststr(request.getRequeststr().replaceAll("<", "[").replaceAll(">", "]") + "---HtmlFilter" );
    chain.doFilter(request, responce,chain);
    responce.setResponcestr(responce.getResponcestr() + "---HtmlFilter" );
    }
    }
    package Filter;
    public class SensitiveFilter implements Filter {
    @Override
    public void doFilter(Request request, Responce responce, Filterchain chain) {
    request.setRequeststr(request.getRequeststr().replaceAll("被就业", "就业").replaceAll("敏感", "") + "---sensitiveFilter");
    chain.doFilter(request, responce,chain);
    responce.setResponcestr(responce.getResponcestr() +  "---sensitiveFilter");
    }
    }

//Request和Responce两个对象

//Responce 类
    public class Responce {
    private String responcestr;
    public String getResponcestr() {
    return responcestr;
    }
    public void setResponcestr(String responcestr) {
    this.responcestr = responcestr;
    }
    }
    //Request 类
    public class Request {
    private String requeststr;
    public String getRequeststr() {
    return requeststr;
    }
    public void setRequeststr(String requeststr) {
    this.requeststr = requeststr;
    }
    }

总结：

先通过代码弄清楚思想，再用java语言实现。

转载于:https://blog.51cto.com/xiaodu1993/1268670