package list 過濾規則 cbc 原來 -html gif java array

背景：要把<script>等<>html標簽替換掉；把敏感詞屏蔽或者替換等； 1.剛開始可能這麽寫：　　　　　　　　　　　　　　　　　　　　

public class Main {

    public static void main(String[] args) {
        String msg = "大家好:),<script>,敏感，被就業，撒的合法了思考的環境法拉盛看到回復";
        MsgProcessor mp = new MsgProcessor();
        mp.setMsg(msg);
        String result 
 
= mp.processor();
        System.out.println(result);
        
    }

}

public class MsgProcessor {
    private String msg;
    
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
    
    public String processor(){
        //process the html tag<>
 

        String r = msg.replace(‘<‘, ‘[‘).replace(‘>‘, ‘]‘);
        //process the sensitive words
        r = r.replace("被就業", "就業")
             .replace("敏感","");
        return r;
    }
    
}

但是上面寫的缺點：

如果還有其他的邏輯，其他的替換，那麽又要在processor裏面寫其他的替換法則，不利於擴展；

2.於是換成下面寫法：　　　　　　　　　　　　　　　　　　

定義接口Filter：

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

處理html tag的類：

public class HTMLFilter implements Filter {
    @Override
    public String doFilter(String str) {
        //process the html tag<>
        String r = str.replace(‘<‘, ‘[‘).replace(‘>‘, ‘]‘);
        return r;
    }
}

處理敏感詞的類：

public class SensitiveFilter implements Filter {

    @Override
    public String doFilter(String str) {
        //process the sensitive words
        String    r = str.replace("被就業", "就業")
                       .replace("敏感","");
        return r;
    }

}

MsgProcessor：

public class MsgProcessor {
    private String msg;
    private Filter[] filters = {new HTMLFilter(), new SensitiveFilter()};
    
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
    
    public String processor(){
        String r = msg;
        
        for(Filter f : filters){
            r = f.doFilter(r);
        }
        
        return r;
    }
}

運行測試main，正確得到結果；

這樣做的好處是：

新添加的規則可以放在filters數組的任意順序上；

新添加的過濾規則可以任意擴展，只要實現Filter接口，並且實現方法，再添加進filters數組就可以了；

但是現在考慮一個問題：

如果已經存在一個過濾器鏈了，要想把這整個過濾器鏈加到原來的邏輯裏面，怎麽做呢？

3.修改為如下：　　　　　　　　　　　　　　

FilterChain.java:

public class FilterChain implements Filter{
    List<Filter> filters = new ArrayList<Filter>();
    
    public FilterChain addFilter(Filter f){
        this.filters.add(f);
        return this;
    }
    
    public String doFilter(String str){
        String r = str;
        
        for(Filter f: filters){
            r = f.doFilter(r);
        }
        return r;
    }
}

MsgProcessor:

public class MsgProcessor {
    private String msg;
    private FilterChain fc;
    
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
    public FilterChain getFc() {
        return fc;
    }
    public void setFc(FilterChain fc) {
        this.fc = fc;
    }
    
    public String processor(){
        return fc.doFilter(this.msg);
    }
}

Main:

public class Main {

    public static void main(String[] args) {
        String msg = "大家好:),<script>,敏感，被就業，撒的合法了思考的環境法拉盛看到回復";
        MsgProcessor mp = new MsgProcessor();
        FilterChain fc = new FilterChain();
        //設置好過濾規則鏈
        fc.addFilter(new HTMLFilter())
          .addFilter(new FaceFilter());
        
        FilterChain fc2 = new FilterChain();
        fc2.addFilter(new SensitiveFilter());
        
        fc.addFilter(fc2);
        
        mp.setMsg(msg);
        mp.setFc(fc);
        
        String result = mp.processor();
        System.out.println(result);
        
    }

}

運行main，打印：

大家好^_^,[script],，就業，撒的合法了思考的環境法拉盛看到回復

4.既處理發送到服務端，也處理從服務端返回到客戶端：　　　　　　　　　　　　

現在只是消息從一頭發往另一頭進行的過濾，而現實之中往往是消息從客戶端發往服務器端，服務器端也有一個反饋， 現在想做這樣一個過濾器，既可以過濾從客戶端發往服務器端的消息，也可以過濾從服務器端返回來的消息； 怎麽做呢？ 正如struts2的interceptor和tomcat等容器的filter都是這樣做的；既處理過去的消息，也處理回來的消息； 把request、response交給過濾器的話，過濾器既能把request對象處理，也能把response對象處理掉； 處理request的過濾器的順序和處理response的過濾器的順序正好是相反的： 這裏簡單使用Request中包含一個string、Response中包含一個string來簡單模擬：

上代碼：

Request：

package com.cy.dp.filter;

public class Request {
    String requestStr;

    public String getRequestStr() {
        return requestStr;
    }

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

View Code

Response：

package com.cy.dp.filter;

public class Response {
    String responseStr;

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

View Code

Filter：

package com.cy.dp.filter;

public interface Filter {
    
    void doFilter(Request request, Response response, FilterChain chain);
    
}

HTMLFilter：

package com.cy.dp.filter;

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()";
    }
    
    
}

View Code

SensitiveFilter：

package com.cy.dp.filter;

public class SensitiveFilter implements Filter {

    @Override
    public void doFilter(Request request, Response response, FilterChain chain) {
        
        //process the sensitive words
        request.requestStr = request.requestStr.replace("被就業", "就業").replace("敏感","") + "----SensitiveFilter()";
        chain.doFilter(request, response, chain);
        
        response.responseStr += "----SensitiveFilter()";
    }

}

View Code

FaceFilter：

package com.cy.dp.filter;

public class FaceFilter implements Filter {
    
    @Override
    public void doFilter(Request request, Response response, FilterChain chain) {
        //process the face
        request.requestStr = request.requestStr.replace(":)", "^_^") + "----FaceFilter()";
        chain.doFilter(request, response, chain);
        
        response.responseStr += "----FaceFilter()";
    }
}

View Code

FilterChain：

package com.cy.dp.filter;

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

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);
    }
}

測試代碼Main：

package com.cy.dp.filter;

public class Main {

    public static void main(String[] args) {
        String msg = "大家好:),<script>,敏感，被就業，撒的合法了思考的環境法拉盛看到回復";
        Request request = new Request();
        request.setRequestStr(msg);
        Response response = new Response();
        response.setResponseStr("response");
        
        //設置好過濾規則鏈
        FilterChain fc = new FilterChain();
        fc.addFilter(new HTMLFilter())
          .addFilter(new SensitiveFilter())
          .addFilter(new FaceFilter());
          
        
        fc.doFilter(request, response, fc);
        
        System.out.println(request.getRequestStr());
        System.out.println(response.getResponseStr());
    }

}

運行結果：

大家好^_^,[script],，就業，撒的合法了思考的環境法拉盛看到回復----HTMLFilter()----SensitiveFilter()----FaceFilter()
response----FaceFilter()----SensitiveFilter()----HTMLFilter()

java設計模式-責任鏈