本文实例讲述了java使用dfa算法实现过滤多家公司自定义敏感字功能。分享给大家供大家参考，具体如下：
背景
因为最近有通讯有个需求，说需要让多家客户公司可以自定义敏感词过滤掉他们自定义的规则，选择了dfa算法来做，不过和以前传统了dfa写法不太一样了
模式图
直接上代码
我要评论
public class keywordfilter {
// private static reentrantreadwritelock lock = new reentrantreadwritelock();
public static map<string, hashmap> currentmap = new concurrenthashmap<string, hashmap>();
public static map nowhash = null;
public static object wordmap;// map子节点
// 不建立对象
private keywordfilter() {
}
private static string getkey(int companyid) {
return "companyid" + companyid;
}
/*
* <p>说明:清扫内容</p>
*
* @author:姚旭民
*
* @data:2017-8-22 上午10:13:11
*/
public static void clear() {
try {
currentmap.clear();
} catch (exception e) {
e.printstacktrace();
} finally {
}
}
/*
* <p>说明:各个渠道的过滤字符</p>
*
* @author:姚旭民
*
* @data:2017-8-20 下午2:55:06
*/
public static void savekeywords(int companyid, list<string> keywords) {
try {
map tempallmap = currentmap;
string key = getkey(companyid);
int l = keywords.size();
int il;
map tempmap;
for (int i = 0; i < l; i++) {
string key2 = keywords.get(i).trim();// 去掉空白
nowhash = currentmap;
il = key2.length();
for (int j = 0; j < il; j++) {
char word = key2.charat(j);
tempmap = (map) nowhash.get(word);
wordmap = nowhash.get(word);
if (wordmap != null) {// 检查数据
if (!tempmap.containskey(key)) {
nowhash.put(key, 0);
}
nowhash = (hashmap) wordmap;
} else {
hashmap<string, string> newwordhash = new hashmap<string, string>();
newwordhash.put(key, "0");
nowhash.put(word, newwordhash);
nowhash = newwordhash;
}
if (j == il - 1) {
nowhash.put(key, "1");
}
}
}
} catch (exception e) {
e.printstacktrace();
} finally {
nowhash = null;
wordmap = null;
}
}
/*
* <p>说明:替换掉对应的渠道规定掉敏感字</p>
*
* @author:姚旭民
*
* @data:2017-8-20 上午11:41:47
*/
public static list<string> repword(int companyid, string txt) {
map tempmap = currentmap;
list<string> result = new arraylist<string>();
string key = getkey(companyid);
nowhash = currentmap;
int l = txt.length();
char word;
string keywordstr = "";
string keystatu;
stringbuilder keyword = new stringbuilder();// 敏感字
for (int i = 0; i < l; i++) {
word = txt.charat(i);
wordmap = nowhash.get(word);
if (wordmap != null) {// 找到类似敏感字的字体，开始查询
keyword.append(word);
object te = nowhash = (hashmap) wordmap;
// 遍历到这一步，就符合完整的关键字模板
if (nowhash.get(key) != null
&& nowhash.get(key).tostring().equals("1")) {// 确定是敏感字，开始替换
if (i < l - 1 && nowhash.get(txt.charat(i + 1)) != null) {// 优先过滤长敏感词，去掉就槟城了优先过滤段敏感词
continue;
}
txt = txt.replaceall(keyword.tostring(), "*");
nowhash = currentmap;
keywordstr += keyword.tostring() + ",";
i = i - keyword.length() + 1;
l = txt.length();// 重新获取字符长度
keyword.delete(0, keyword.length());// 清空数据
}
} else {// 这个字不是敏感字，直接排除
nowhash = currentmap;
keyword.delete(0, keyword.length());// 清空数据
continue;
}
}
// 清除内存指向
nowhash = null;
wordmap = null;
result.add(txt);
result.add(keywordstr.length() - 1 > 0 ? keywordstr.substring(0,
keywordstr.length() - 1) : keywordstr);
return result;
}
/*
* <p>说明:检查是否存在敏感字</p>
*
* @author:姚旭民
*
* @data:2017-8-20 下午3:00:06 专门设计成私有的，如果没有理由，别改动他
*/
private static int checkkeywords(string txt, int companyid, int begin) {
int result = 0;
string key = getkey(companyid);
try {
nowhash = currentmap;
int l = txt.length();
char word = 0;
for (int i = begin; i < l; i++) {
word = txt.charat(i);
wordmap = nowhash.get(word);
if (wordmap != null) {
result++;
nowhash = (hashmap) wordmap;
if (((string) nowhash.get(key)).equals("1")) {
nowhash = null;
wordmap = null;
return result;
}
} else {
result = 0;
break;
}
}
} catch (exception e) {
e.printstacktrace();
} finally {
nowhash = null;
wordmap = null;
return result;
}
}
/*
* <p>说明:返回检查的文本中包含的敏感字</p>
*
* @author:姚旭民
*
* @data:2017-8-20 下午3:32:53
*/
public static string gettxtkeywords(string txt, int companyid) {
string result = null;
stringbuilder temp = new stringbuilder();
string key;
int l = txt.length();
for (int i = 0; i < l;) {
int len = checkkeywords(txt, companyid, i);
if (len > 0) {
key = (txt.substring(i, i + len));// 挑选出来的关键字
temp.append(key + ",");
txt = txt.replaceall(key, "");// 挑选出来的关键字替换成空白，加快挑选速度
l = txt.length();
} else {
i++;
}
}
if (temp.length() > 0) {
result = temp.substring(0, temp.length() - 1);
}
return result;
}
/*
* <p>说明:判断文中是否包含渠道规定的敏感字</p>
*
* @author:姚旭民
*
* @data:2017-8-20 下午3:33:19
*/
public boolean iskeywords(string txt, int companyid) {
for (int i = 0; i < txt.length(); i++) {
int len = checkkeywords(txt, companyid, i);
if (len > 0) {
return true;
}
}
return false;
}
public static void main(string[] arg) {
list<string> keywords = new arraylist<string>();
keywords.add("傻×");
keywords.add("汉奸");
keywords.add("草");
keywords.add("草泥马");
keywordfilter.savekeywords(1, keywords);
string txt = "是傻×汉奸傻a傻b傻c傻d汉奸傻×草泥马";
list<string> list = repword(1, txt);
system.out.println("文中包含的敏感字为:" + list.get(1));
system.out.println("原文:" + txt);
system.out.println("敏感字过滤后:" + list.get(0));
}
}
更多关于java算法相关内容感兴趣的读者可查看本站专题：《java数据结构与算法教程》、《java字符与字符串操作技巧总结》、《java操作dom节点技巧总结》、《java文件与目录操作技巧汇总》和《java缓存操作技巧汇总》
希望本文所述对大家java程序设计有所帮助。
如对本文有疑问， 点击进行留言回复！！
![[杭电多校2020]第一场 1004 Distinct Sub-palindromes](http://www.lhsxpumps.com/_images5/10qianwan/20200724/s_0_202007241733388592.png)
[杭电多校2020]第一场 1004 Distinct Sub-palindromes
Swift -- 将本地生成的UIImage进行持久化保存（存到文件中fileManager.createFile）
网友评论