fix:抛出PatternSyntaxException

Author: ban-xiu

core/src/main/java/com/taobao/arthas/core/util/RegexCacheManager.java

@@ -2,7 +2,6 @@
 
 import com.taobao.arthas.core.shell.term.impl.http.session.LRUCache;
 import java.util.regex.Pattern;
-import java.util.regex.PatternSyntaxException;
 
 /**
  * 正则表达式缓存管理器
@@ -44,14 +43,11 @@ public Pattern getPattern(String regex) {
         synchronized (regexCache) {
             pattern = regexCache.get(regex);
             if (pattern == null) {
-                try {
-                    // 缓存未命中，编译正则表达式
-                    pattern = Pattern.compile(regex);
-                    regexCache.put(regex, pattern);
-                } catch (PatternSyntaxException e) {
-                    // 捕获正则表达式语法错误，返回null，保持与原来相同的错误处理行为
-                    return null;
-                }
+                // 缓存未命中，编译正则表达式
+                // 不捕获PatternSyntaxException，让异常向上抛出，以便及时发现无效的正则表达式
+                pattern = Pattern.compile(regex);
+                // 缓存编译结果
+                regexCache.put(regex, pattern);
             }
         }
 

core/src/main/java/com/taobao/arthas/core/util/matcher/RegexMatcher.java

@@ -9,17 +9,24 @@
  */
 public class RegexMatcher implements Matcher<String> {
 
-    private final Pattern pattern;
+    private final String pattern;
+    private Pattern compiledPattern;
 
     public RegexMatcher(String pattern) {
-        // 使用正则表达式缓存
-        this.pattern = RegexCacheManager.getInstance().getPattern(pattern);
+        this.pattern = pattern;
     }
 
     @Override
     public boolean matching(String target) {
-        return null != target
-                && null != pattern
-                && pattern.matcher(target).matches();
+        if (null == target || null == pattern) {
+            return false;
+        }
+
+        // 在第一次matching时才编译正则表达式
+        if (compiledPattern == null) {
+            compiledPattern = RegexCacheManager.getInstance().getPattern(pattern);
+        }
+        
+        return compiledPattern != null && compiledPattern.matcher(target).matches();
     }
 }