Java设计模式---ChainOfResponsibility责任链模式
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2022-03-20 20:09:03
参考于 : 大话设计模式 马士兵设计模式视频 代码参考于马士兵设计模式视频 写在开头：职责链模式：使多个对象都有机会处理请求，从而避免请求的发送者和接收者之间的耦合关系 图来自大话设计模式，下面我的代码中，Clien是t依赖于Handler1和Handler2的，不过可以使用配置文件或者直接给Fil ......
参考于 :
大话设计模式
马士兵设计模式视频
代码参考于马士兵设计模式视频
写在开头：职责链模式：使多个对象都有机会处理请求，从而避免请求的发送者和接收者之间的耦合关系
图来自大话设计模式，下面我的代码中，clien是t依赖于handler1和handler2的，不过可以使用配置文件或者直接给filter集合初始化来解决这种依赖。
1.场景
在网上评论一句话，往往会经过一系列的处理，有没有敏感词之类，现在我们来模拟一下。
把<html>，o.o，和谐
换成 [html]，^v^，/*河蟹*/
2.不使用职责链模式
package com.dingyu.chainofresponsibility;
/**
* 重点在于模式，故逻辑暂时不考虑
*
* @author dingyu
*
*/
public class client01 {
public static void main(string[] args) {
string s = "<html>，o.o，和谐";
s = s.replace("<", "[").replace(">", "]").replace("和谐", "/*河蟹*/").replace("o.o", "^v^");
system.out.println(s);
}
}
缺点：过滤无法复用，无法记录过滤顺序。
3.使用职责链模式
package com.dingyu.chainofresponsibility;
/**
* 过滤器,dofilter处理msg字符串
* @author dingyu
*
*/
public interface filter {
public string dofilter(string msg);
}
package com.dingyu.chainofresponsibility;
/**
* 处理html符号
* 测试用的，逻辑不是很严谨
* @author dingyu
*
*/
public class htmlfilter implements filter {
@override
public string dofilter(string msg) {
return msg.replace("<", "[").replace(">", "]");
}
}
package com.dingyu.chainofresponsibility;
/**
* 过滤敏感词汇
* @author dingyu
*
*/
public class sensitivewordfilter implements filter {
@override
public string dofilter(string msg) {
return msg.replace("和谐", "/*河蟹*/");
}
}
package com.dingyu.chainofresponsibility;
/**
* 处理符号
* @author dingyu
*
*/
public class symbolfilter implements filter {
@override
public string dofilter(string msg) {
return msg.replace("o.o", "^v^");
}
}
package com.dingyu.chainofresponsibility;
import java.util.arraylist;
import java.util.list;
public class client {
private static list<filter> filters = new arraylist<filter>();
private static int index = 0;
public static void main(string[] args) {
string s = "<html>，o.o，和谐";
filters.add(new htmlfilter());
filters.add(new symbolfilter());
filters.add(new sensitivewordfilter());
for (filter filter : filters) {
s = filter.dofilter(s);
}
system.out.println(s);
}
}
虽然使用职责链模式，但仍然有缺点，上面的顺序是先html,然后symbol，最后sensitiveword，这三个构成一个过滤链条，如果有一天我需要把另一个过滤链条插入到这根链条中间，实现起来很麻烦。
4.改进职责链模式
package com.dingyu.chainofresponsibility;
import java.util.arraylist;
import java.util.list;
/**
*
* @author dingyu
*
*/
public class filterchain implements filter {
private list<filter> filters = new arraylist<filter>();
public void add(filter filter) {
filters.add(filter);
}
public list<filter> getfilters() {
return filters;
}
@override
public string dofilter(string msg) {
for (filter filter : filters) {
msg = filter.dofilter(msg);
}
return msg;
}
}
package com.dingyu.chainofresponsibility;
import java.util.arraylist;
import java.util.list;
public class client {
// private static list<filter> filters = new arraylist<filter>();
public static void main(string[] args) {
string s = "<html>，o.o，和谐";
// 链条1
filterchain chain1 = new filterchain();
chain1.add(new htmlfilter());
// 链条2
filterchain chain2 = new filterchain();
chain2.add(new htmlfilter());
chain2.add(new sensitivewordfilter());
// 链条2插到链条1后
chain1.add(chain2);
chain1.add(new symbolfilter());
s = chain1.dofilter(s);
system.out.println(s);
// filters.add(new htmlfilter());
// filters.add(new symbolfilter());
// filters.add(new sensitivewordfilter());
// for (filter filter : filters) {
// s = filter.dofilter(s);
// }
// system.out.println(s);
}
}
建议debug ， eclipse快捷键
5. 职责链实现双向过滤
思路类似于递归，建议使用debug一步步调试。
package com.dingyu.chainofresponsibility;
/**
* 过滤器,dofilter处理msg字符串
*
* @author dingyu
*
*/
public interface filter {
// public string dofilter(string msg);
public void dofilter(request request, reponse reponse, filterchain filterchain);
}
package com.dingyu.chainofresponsibility;
/**
* 处理html符号 测试用的，逻辑不是很严谨
*
* @author dingyu
*
*/
public class htmlfilter implements filter {
@override
public void dofilter(request request, reponse reponse, filterchain filterchain) {
request.getrequestmsg().replace("<", "[").replace(">", "]");
filterchain.dofilter(request, reponse, filterchain);
reponse.setreponsemsg(reponse.getreponsemsg() + "-----htmlfilter");
}
// @override
// public string dofilter(string msg) {
// return msg.replace("<", "[").replace(">", "]");
// }
}
package com.dingyu.chainofresponsibility;
/**
* 过滤敏感词汇
*
* @author dingyu
*
*/
public class sensitivewordfilter implements filter {
@override
public void dofilter(request request, reponse reponse, filterchain filterchain) {
request.getrequestmsg().replace("和谐", "/*河蟹*/");
filterchain.dofilter(request, reponse, filterchain);
reponse.setreponsemsg(reponse.getreponsemsg() + "-----sensitivewordfilter");
}
// @override
// public string dofilter(string msg) {
// return msg.replace("和谐", "/*河蟹*/");
// }
}
package com.dingyu.chainofresponsibility;
/**
* 处理符号
*
* @author dingyu
*
*/
public class symbolfilter implements filter {
@override
public void dofilter(request request, reponse reponse, filterchain filterchain) {
request.getrequestmsg().replace("o.o", "^v^");
filterchain.dofilter(request, reponse, filterchain);
reponse.setreponsemsg(reponse.getreponsemsg() + "-----symbolfilter");
}
// @override
// public string dofilter(string msg) {
// return msg.replace("o.o", "^v^");
// }
}
package com.dingyu.chainofresponsibility;
import java.util.arraylist;
import java.util.list;
/**
*
* @author dingyu
*
*/
public class filterchain implements filter {
private list<filter> filters = new arraylist<filter>();
private int index=-1;
public void add(filter filter) {
filters.add(filter);
}
public list<filter> getfilters() {
return filters;
}
// @override
// public string dofilter(string msg) {
// for (filter filter : filters) {
// msg = filter.dofilter(msg);
// }
// return msg;
// }
@override
public void dofilter(request request, reponse reponse, filterchain filterchain) {
if (index == filters.size()-1)
return;
index++;
filters.get(index).dofilter(request, reponse, filterchain);
}
}
package com.dingyu.chainofresponsibility;
public class client03 {
public static void main(string[] args) {
request request = new request();
reponse reponse = new reponse();
request.setrequestmsg("<html>，o.o，和谐");
reponse.setreponsemsg("hahahahaha");
filterchain chain = new filterchain();
chain.add(new htmlfilter());
chain.add(new sensitivewordfilter());
chain.add(new symbolfilter());
chain.dofilter(request, reponse, chain);
system.out.println(request.getrequestmsg());
system.out.println(reponse.getreponsemsg());
}
}