fix：避免调用方 显示调用API 触发查找树 优化；并通过内置锁，避免因并行树优化 可能造成的不可预知结果 和 无效重复的 树优化操作

hutool-core/src/main/java/cn/hutool/core/text/dfa/Automaton.java

@@ -4,141 +4,177 @@ import java.util.*;
 
 /**
  * <p>
- *
  * 基于非确定性有穷自动机（NFA） 实现的多模匹配工具
+ * </p>
  *
  * @author renyp
  */
 public class Automaton {
-	private final Node root;
+    /**
+     * AC树的根节点
+     */
+    private final Node root;
+    /**
+     * 标记是否需要构建AC自动机，做树优化
+     */
+    private volatile boolean needBuildAC;
 
-	/**
+    /**
-	 * 默认构造
+     * 内置锁，防止并发场景，并行建AC树，造成不可预知结果
-	 */
+     */
-	public Automaton() {
+    private final Object lock;
-		this.root = new Node();
-	}
 
-	/**
+    /**
-	 * 构造函数 并 初始化词库
+     * 默认构造
-	 *
+     */
-	 * @param words 添加的新词
+    public Automaton() {
-	 */
+        this.root = new Node();
-	public Automaton(String... words) {
+        this.needBuildAC = true;
-		this();
+        this.lock = new Object();
-		this.insert(words);
+    }
-	}
 
-	/**
+    /**
-	 * 词库添加新词，初始化查找树
+     * 构造函数 并 初始化词库
-	 *
+     *
-	 * @param word 添加的新词
+     * @param words 添加的新词
-	 */
+     */
-	public void insert(String word) {
+    public Automaton(String... words) {
-		Node p = root;
+        this();
-		for (char curr : word.toCharArray()) {
+        this.insert(words);
-			int ind = curr;
+    }
-			if (p.next.get(ind) == null) {
-				p.next.put(ind, new Node());
-			}
-			p = p.next.get(ind);
-		}
-		p.flag = true;
-		p.str = word;
-	}
 
-	/**
+    /**
-	 * 词库批量添加新词，初始化查找树
+     * 词库添加新词，初始化查找树
-	 *
+     *
-	 * @param words 添加的新词
+     * @param word 添加的新词
-	 */
+     */
-	public void insert(String... words) {
+    public void insert(String word) {
-		for (String word : words) {
+        needBuildAC = true;
-			this.insert(word);
+        Node p = root;
-		}
+        for (char curr : word.toCharArray()) {
-	}
+            int ind = curr;
+            if (p.next.get(ind) == null) {
+                p.next.put(ind, new Node());
+            }
+            p = p.next.get(ind);
+        }
+        p.flag = true;
+        p.str = word;
+    }
 
-	/**
+    /**
-	 * 构建基于NFA模型的 AC自动机
+     * 词库批量添加新词，初始化查找树
-	 */
+     *
-	public void buildAc() {
+     * @param words 添加的新词
-		Queue<Node> queue = new LinkedList<>();
+     */
-		Node p = root;
+    public void insert(String... words) {
-		for (Integer key : p.next.keySet()) {
+        for (String word : words) {
-			p.next.get(key).fail = root;
+            this.insert(word);
-			queue.offer(p.next.get(key));
+        }
-		}
+    }
-		while (!queue.isEmpty()) {
-			Node curr = queue.poll();
-			for (Integer key : curr.next.keySet()) {
-				Node fail = curr.fail;
-				// 查找当前节点匹配失败，他对应等效匹配的节点是哪个
-				while (fail != null && fail.next.get(key) == null) {
-					fail = fail.fail;
-				}
-				// 代码到这，有两种可能，fail不为null，说明找到了fail；fail为null，没有找到，那么就把fail指向root节点（当到该节点匹配失败，那么从root节点开始重新匹配）
-				if (fail != null) {
-					fail = fail.next.get(key);
-				} else {
-					fail = root;
-				}
-				curr.next.get(key).fail = fail;
-				queue.offer(curr.next.get(key));
-			}
-		}
-	}
 
-	/**
+    /**
-	 * @param text 查询的文本（母串）
+     * 构建基于NFA模型的 AC自动机
-	 */
+     */
-	public List<FoundWord> find(String text) {
+    private void buildAc() {
-		return this.find(text, true);
+        Queue<Node> queue = new LinkedList<>();
-	}
+        Node p = root;
+        for (Integer key : p.next.keySet()) {
+            p.next.get(key).fail = root;
+            queue.offer(p.next.get(key));
+        }
+        while (!queue.isEmpty()) {
+            Node curr = queue.poll();
+            for (Integer key : curr.next.keySet()) {
+                Node fail = curr.fail;
+                // 查找当前节点匹配失败，他对应等效匹配的节点是哪个
+                while (fail != null && fail.next.get(key) == null) {
+                    fail = fail.fail;
+                }
+                // 代码到这，有两种可能，fail不为null，说明找到了fail；fail为null，没有找到，那么就把fail指向root节点（当到该节点匹配失败，那么从root节点开始重新匹配）
+                if (fail != null) {
+                    fail = fail.next.get(key);
+                } else {
+                    fail = root;
+                }
+                curr.next.get(key).fail = fail;
+                queue.offer(curr.next.get(key));
+            }
+        }
+        needBuildAC = false;
+    }
 
-	/**
+    /**
-	 * @param text           查找的文本（母串）
+     * @param text 查询的文本（母串）
-	 * @param isDensityMatch 是否密集匹配
+     */
-	 */
+    public List<FoundWord> find(String text) {
-	public List<FoundWord> find(String text, boolean isDensityMatch) {
+        return this.find(text, true);
-		List<FoundWord> ans = new ArrayList<>();
+    }
-		Node p = root, k = null;
-		for (int i = 0, len = text.length(); i < len; i++) {
-			int ind = text.charAt(i);
-			// 状态转移(沿着fail指针链接的链表，此处区别于DFA模型)
-			while (p != null && p.next.get(ind) == null) {
-				p = p.fail;
-			}
-			if (p == null) {
-				p = root;
-			} else {
-				p = p.next.get(ind);
-			}
-			// 提取结果(沿着fail指针链接的链表，此处区别于DFA模型)
-			k = p;
-			while (k != null) {
-				if (k.flag) {
-					ans.add(new FoundWord(k.str, k.str, i - k.str.length() + 1, i));
-					if (!isDensityMatch) {
-						p = root;
-						break;
-					}
-				}
-				k = k.fail;
-			}
-		}
-		return ans;
-	}
 
-	private static class Node {
+    /**
+     * @param text           查找的文本（母串）
+     * @param isDensityMatch 是否密集匹配
+     */
+    public List<FoundWord> find(String text, boolean isDensityMatch) {
+        // double check，防止重复无用的 buildAC
+        if (needBuildAC) {
+            synchronized (lock) {
+                if (needBuildAC) {
+                    this.buildAc();
+                }
+            }
+        }
+        List<FoundWord> ans = new ArrayList<>();
+        Node p = root, k = null;
+        for (int i = 0, len = text.length(); i < len; i++) {
+            int ind = text.charAt(i);
+            // 状态转移(沿着fail指针链接的链表，此处区别于DFA模型)
+            while (p != null && p.next.get(ind) == null) {
+                p = p.fail;
+            }
+            if (p == null) {
+                p = root;
+            } else {
+                p = p.next.get(ind);
+            }
+            // 提取结果(沿着fail指针链接的链表，此处区别于DFA模型)
+            k = p;
+            while (k != null) {
+                if (k.flag) {
+                    ans.add(new FoundWord(k.str, k.str, i - k.str.length() + 1, i));
+                    if (!isDensityMatch) {
+                        p = root;
+                        break;
+                    }
+                }
+                k = k.fail;
+            }
+        }
+        return ans;
+    }
 
-		boolean flag;
+    private static class Node {
-		Node fail;
-		String str;
-		Map<Integer, Node> next;
 
-		public Node() {
+        /**
-			this.flag = false;
+         * 当前节点是否是一个单词的结尾
-			next = new HashMap<>();
+         */
-		}
+        boolean flag;
-	}
+        /**
+         * 指向 当前节点匹配失败应该跳转的下个节点
+         */
+        Node fail;
+        /**
+         * 以当前节点结尾的单词
+         */
+        String str;
+        /**
+         * 当前节点的子节点
+         */
+        Map<Integer, Node> next;
+
+        public Node() {
+            this.flag = false;
+            next = new HashMap<>();
+        }
+    }
 }

hutool-core/src/test/java/cn/hutool/core/text/dfa/AutomatonTest.java

@@ -17,7 +17,7 @@ public class AutomatonTest extends TestCase {
 		Automaton automaton = new Automaton();
 		WordTree wordTree = new WordTree();
 		automaton.insert("say", "her", "he", "she", "shr");
-		automaton.buildAc();
+//		automaton.buildAc();
 		wordTree.addWords("say", "her", "he", "she", "shr");
 
 		StopWatch stopWatch = new StopWatch();
@@ -51,7 +51,7 @@ public class AutomatonTest extends TestCase {
 		Automaton automaton = new Automaton();
 		WordTree wordTree = new WordTree();
 		automaton.insert("say", "her", "he", "she", "shr");
-		automaton.buildAc();
+//		automaton.buildAc();
 		wordTree.addWords("say", "her", "he", "she", "shr");
 
 		StopWatch stopWatch = new StopWatch();
@@ -84,7 +84,7 @@ public class AutomatonTest extends TestCase {
 		stopWatch.start("automaton_char_buid_find");
 		Automaton automatonLocal = new Automaton();
 		automatonLocal.insert("say", "her", "he", "she", "shr");
-		automatonLocal.buildAc();
+//		automatonLocal.buildAc();
 		List<FoundWord> ans1 = automatonLocal.find(input);
 		stopWatch.stop();
 		assertEquals("she,he,her,say", ans1.stream().map(FoundWord::getWord).collect(Collectors.joining(",")));
@@ -118,7 +118,7 @@ public class AutomatonTest extends TestCase {
 		stopWatch.start("automaton_cn_build_find");
 		Automaton automatonLocal = new Automaton();
 		automatonLocal.insert("赵", "赵啊", "赵啊三");
-		automatonLocal.buildAc();
+//		automatonLocal.buildAc();
 
 		final List<FoundWord> result = automatonLocal.find(input);
 		stopWatch.stop();
@@ -156,7 +156,7 @@ public class AutomatonTest extends TestCase {
 
 		Automaton automatonLocal = new Automaton();
 		automatonLocal.insert("赵", "赵啊", "赵啊三");
-		automatonLocal.buildAc();
+//		automatonLocal.buildAc();
 
 		stopWatch.start("automaton_cn_find");
 		final List<FoundWord> result = automatonLocal.find(input);
@@ -196,7 +196,7 @@ public class AutomatonTest extends TestCase {
 
 		Automaton automatonLocal = new Automaton();
 		automatonLocal.insert("赵", "赵啊", "赵啊三");
-		automatonLocal.buildAc();
+//		automatonLocal.buildAc();
 
 		stopWatch.start("automaton_cn_find_not_density");
 		final List<FoundWord> result = automatonLocal.find(input, false);