模仿javax包下的Filter和FilterChain

笔记

接上上次的责任链模式尾巴，以下代码是仿javax包中的Filter和FilterChain

请求流程图：

U_JAK__`5_SPYPE~T`2VJZ5.png

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public interface Filter {
    void doFilter(Request request,Response response,FilterChain chain);
}
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public class FilterChain {
    List<Filter> filters = new ArrayList<>();
    int index = 0;

    public FilterChain add(Filter filter){
        filters.add(filter);
        return this;
    }

    public void doFilter(Request request,Response response,FilterChain chain){
        if(index == filters.size()){
            return;
        }
        Filter filter = filters.get(index);
        index++;
        filter.doFilter(request,response,chain);
    }
}
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@Data
public class Request {
    private String str;
}
-----------------------------
@Data
public class Response {
    private String str;
}
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public class HTMLFilter implements Filter {
    @Override
    public void doFilter(Request request,Response response,FilterChain chain) {
        request.setStr(request.getStr().replaceAll("<", "[").replaceAll(">", "]"));
        System.out.println("HTMLFilter(request)");
        chain.doFilter(request,response,chain);
        response.setStr(response.getStr() + "--- HTMLFilter...");
    }
}
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public class SensitiveFilter implements Filter {
    @Override
    public void doFilter(Request request,Response response,FilterChain chain) {
        request.setStr(request.getStr().replaceAll("996", "955"));
        System.out.println("SensitiveFilter(request)");
        chain.doFilter(request,response,chain);
        response.setStr(response.getStr() + "--- SensitiveFilter...");
    }
}
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public class Main {
    public static void main(String[] args) {
        Request request = new Request();
        Response response = new Response();
        response.setStr("response");
        request.setStr("大家好:)，<script>，欢迎访问www.oldman.run，大家都是996");
        FilterChain chain = new FilterChain();
        chain.add(new HTMLFilter()).add(new SensitiveFilter());
        chain.doFilter(request,response,chain);
        System.out.println(request.getStr());
        System.out.println(response.getStr());
    }
}

执行结果：

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HTMLFilter(request)
SensitiveFilter(request)
大家好:)，[script]，欢迎访问www.oldman.run，大家都是955
response--- SensitiveFilter...--- HTMLFilter...

从结果中可以看到整个request和response的执行顺序，去是1->2，回来是2->1。