简介

首先任务会先到消息处理器.
消息处理器调用doFilter方法,也就是处理链中的doFilter.
处理链的doFilter是循环调用它内部的一个个处理类.
处理类的doFilter是详细处理

接口

规范实现类

public interface Filter {
    String doFilter(String str);
}

具体处理类

HtmlFilter

public class HtmlFilter implements Filter {
    @Override
    public String doFilter(String str) {
        //处理特殊字符
        String replace = str.replace('<', '[')
                .replace('>', ']');
        return replace;
    }
}

SesitiveFilte

public class SesitiveFilte implements Filter {
    @Override
    public String doFilter(String str) {
        //处理敏感字
        String r = str.replace("敏感", "**")
                .replace("不好", "**");
        return r;
    }
}

FaceFilter

public class FaceFilter implements Filter {
    @Override
    public String doFilter(String str) {
        //处理特殊字符
        String replace = str.replace(':', '*');
        return replace;
    }
}

责任链

public class FilterChain implements Filter {
    List<Filter> filters = new ArrayList<Filter>();
    //把责任添加进去
    public FilterChain addFilter(Filter f) {
        this.filters.add(f);
        return this;
    }
    @Override
    public String doFilter(String str) {
        String r = str;
        //挨个调用每个filter的处理方法,一直在里面循环直到循环结束
        for (Filter filter : filters) {
            r = filter.doFilter(r);
        }
        return r;
    }
}

消息处理程序

这个是启动责任链的程序

@Data
public class MsgProcessor {
    //保存消息
    private String msg;
    //保存责任链
    FilterChain fc;
    public String process() {
        return fc.doFilter(msg);
    }
}

主程序

String msg = "大家好:), <script>: 敏感词, 不好";
//初始化消息处理器
MsgProcessor mp = new MsgProcessor();
//把要处理的消息添加进去
mp.setMsg(msg);
//初始化,责任链
FilterChain fc = new FilterChain();
//添加过滤器,链式调用
fc.addFilter(new HtmlFilter()).addFilter(new SesitiveFilte());
//添加子链,这个子责任链是挂到主责任链上面的
FilterChain fc2 = new FilterChain();
fc2.addFilter(new FaceFilter());
//把子链添加到责任链中
fc.addFilter(fc2);
//把责任链添加到消息处理器中
mp.setFc(fc);
//进行消息处理
String result = mp.process();
System.out.println(result);

web中的责任链

Filter接口

public interface Filter {
    //给他请求类和响应类,他来调用责任链处理里面的
    void doFilter(Request request, Response response, FilterChain filterChain);
}

具体处理

FaceFilter

 public class FaceFilter implements Filter {
    @Override
    public void doFilter(Request request, Response response, FilterChain filterChain) {
        //请求处理特殊字符
        String str = request.getRequestStr()
        .replace(':', '*');
        request.setRequestStr(str);
        filterChain.doFilter(request, response, filterChain);
        //响应处理的
        String responseMsg = response.getResponseStr() + "---FaceFilter";
        response.setResponseStr(responseMsg);
    }
}

HtmlFilter

 public class HtmlFilter implements Filter {
    @Override
    public void doFilter(Request request, Response response, FilterChain filterChain) {
        //请求处理特殊字符
        String str = request.getRequestStr()
        .replace('<', '[')
        .replace('>', ']');
        request.setRequestStr(str);
        filterChain.doFilter(request, response, filterChain);
        //响应处理的
        String responseMsg = response.getResponseStr() + "---HtmlFilter";
        response.setResponseStr(responseMsg);
    }
}

SesitiveFilte

public class SesitiveFilte implements Filter {
    @Override
    public void doFilter(Request request, Response response, FilterChain filterChain) {
        //请求处理特殊字符
        String str = request.getRequestStr()
        .replace("敏感", "**")
        .replace("不好", "**");
        request.setRequestStr(str);
        filterChain.doFilter(request, response, filterChain);
        //响应处理的
        String responseMsg = response.getResponseStr() + "---SesitiveFilte";
        response.setResponseStr(responseMsg);
    }
}

责任链

public class FilterChain implements Filter {
    List<Filter> filters = new ArrayList<Filter>();
    //记录运行到那个filter上
    int index = 0;
    public FilterChain addFilter(Filter f) {
        this.filters.add(f);
        return this;
    }
    @Override
    public void doFilter(Request request, Response response, FilterChain filterChain) {
        //没有filter了
        if (index == filters.size()) {
            return;
        }
        //取出filter
        Filter f = filters.get(index);
        index++;
        f.doFilter(request, response, filterChain);
    }
}

消息处理程序

@Data
public class MsgProcessor {
    //保存请求
    private Request request;
    //保存响应
    private Response response;
    //保存调用链
    private FilterChain filterChain;
    public void process() {
        //调用责任链处理
        filterChain.doFilter(this.getRequest(), this.getResponse(), this.getFilterChain());
    }
}

主程序

//提前准备好请求和响应
Request request = new Request();
Response response = new Response();
String msg = "大家好:), <script>: 敏感词, 不好";
//请求需要处理的
request.setRequestStr(msg);
//响应需要处理的
response.setResponseStr("abc---123");
//初始化消息处理器
MsgProcessor mp = new MsgProcessor();
//把要处理的请求或者响应添加进去
mp.setRequest(request);
mp.setResponse(response);
//初始化,责任链
FilterChain fc = new FilterChain();
//添加过滤器
fc.addFilter(new HtmlFilter()).addFilter(new SesitiveFilte());
//添加子链,这个子责任链是挂到主责任链上面的
FilterChain fc2 = new FilterChain();
fc2.addFilter(new FaceFilter());
//把子链添加到责任链中
fc.addFilter(fc2);
//把责任链添加到消息处理器中
mp.setFilterChain(fc);
//进行消息处理
mp.process();
System.out.println(request.getRequestStr());
System.out.println(response.getResponseStr());