fix: 修复文件类型匹配和知识库切割配置问题

1. 修复 ResourceLoaderFactory 文件扩展名匹配问题
   - 去除扩展名前导点，确保 .pdf 能正确匹配 PDF 解析器
   - 修复 PDF/Word/Excel 等文件走错解析逻辑的问题

2. 优化文本切割器动态配置
   - CharacterTextSplitter 和 ExcelTextSplitter 支持从知识库读取配置
   - 根据 kid 查询 separator、textBlockSize、overlapChar
   - 查询失败时降级使用默认配置

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ruoyi-modules/ruoyi-chat/src/main/java/org/ruoyi/factory/ResourceLoaderFactory.java

@@ -1,6 +1,7 @@
 package org.ruoyi.factory;
 
 import lombok.AllArgsConstructor;
+import org.apache.commons.lang3.StringUtils;
 import org.ruoyi.constant.FileTypeConstants;
 import org.ruoyi.service.knowledge.ResourceLoader;
 import org.ruoyi.service.knowledge.impl.loader.*;
@@ -16,6 +17,7 @@ public class ResourceLoaderFactory {
     private final ExcelTextSplitter excelTextSplitter;
 
     public ResourceLoader getLoaderByFileType(String fileType) {
+        fileType = StringUtils.removeStart(fileType, ".");
         if (FileTypeConstants.isTextFile(fileType)) {
             return new TextFileLoader(characterTextSplitter);
         } else if (FileTypeConstants.isWord(fileType)) {

ruoyi-modules/ruoyi-chat/src/main/java/org/ruoyi/service/knowledge/impl/split/CharacterTextSplitter.java

@@ -1,7 +1,10 @@
 package org.ruoyi.service.knowledge.impl.split;
 
+import lombok.AllArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.ruoyi.common.core.utils.StringUtils;
+import org.ruoyi.domain.vo.knowledge.KnowledgeInfoVo;
+import org.ruoyi.service.knowledge.IKnowledgeInfoService;
 import org.ruoyi.service.knowledge.TextSplitter;
 import org.springframework.context.annotation.Primary;
 import org.springframework.stereotype.Component;
@@ -13,14 +16,37 @@ import java.util.List;
 @Component
 @Slf4j
 @Primary
+@AllArgsConstructor
 public class CharacterTextSplitter implements TextSplitter {
 
+    private final IKnowledgeInfoService knowledgeInfoService;
+
     @Override
     public List<String> split(String content, String kid) {
-        // 使用默认配置
+        // 默认配置值
         String knowledgeSeparator = "#";
-        int textBlockSize = 10000;
+        int textBlockSize = 1000;
-        int overlapChar = 500;
+        int overlapChar = 50;
+
+        // 根据知识库ID查询配置，覆盖默认值
+        if (StringUtils.isNotBlank(kid)) {
+            try {
+                KnowledgeInfoVo info = knowledgeInfoService.queryById(Long.parseLong(kid));
+                if (info != null) {
+                    if (StringUtils.isNotBlank(info.getSeparator())) {
+                        knowledgeSeparator = info.getSeparator();
+                    }
+                    if (info.getTextBlockSize() != null && info.getTextBlockSize() > 0) {
+                        textBlockSize = info.getTextBlockSize().intValue();
+                    }
+                    if (info.getOverlapChar() != null && info.getOverlapChar() > 0) {
+                        overlapChar = info.getOverlapChar().intValue();
+                    }
+                }
+            } catch (Exception e) {
+                log.warn("查询知识库配置失败，使用默认配置, kid={}", kid, e);
+            }
+        }
 
         List<String> chunkList = new ArrayList<>();
         if (content.contains(knowledgeSeparator) && StringUtils.isNotBlank(knowledgeSeparator)) {

ruoyi-modules/ruoyi-chat/src/main/java/org/ruoyi/service/knowledge/impl/split/ExcelTextSplitter.java

@@ -3,6 +3,8 @@ package org.ruoyi.service.knowledge.impl.split;
 import lombok.AllArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.ruoyi.common.core.utils.StringUtils;
+import org.ruoyi.domain.vo.knowledge.KnowledgeInfoVo;
+import org.ruoyi.service.knowledge.IKnowledgeInfoService;
 import org.ruoyi.service.knowledge.TextSplitter;
 import org.springframework.stereotype.Component;
 
@@ -15,13 +17,34 @@ import java.util.List;
 @Slf4j
 public class ExcelTextSplitter implements TextSplitter {
 
+    private final IKnowledgeInfoService knowledgeInfoService;
 
     @Override
     public List<String> split(String content, String kid) {
-        // 使用默认配置
+        // 默认配置
         String knowledgeSeparator = "#";
-        int textBlockSize = 10000;
+        int textBlockSize = 1000;
-        int overlapChar = 500;
+        int overlapChar = 50;
+
+        // 根据知识库ID查询配置，覆盖默认值
+        if (StringUtils.isNotBlank(kid)) {
+            try {
+                KnowledgeInfoVo info = knowledgeInfoService.queryById(Long.parseLong(kid));
+                if (info != null) {
+                    if (StringUtils.isNotBlank(info.getSeparator())) {
+                        knowledgeSeparator = info.getSeparator();
+                    }
+                    if (info.getTextBlockSize() != null && info.getTextBlockSize() > 0) {
+                        textBlockSize = info.getTextBlockSize().intValue();
+                    }
+                    if (info.getOverlapChar() != null && info.getOverlapChar() > 0) {
+                        overlapChar = info.getOverlapChar().intValue();
+                    }
+                }
+            } catch (Exception e) {
+                log.warn("查询知识库配置失败，使用默认配置, kid={}", kid, e);
+            }
+        }
         List<String> chunkList = new ArrayList<>();
         if (content.contains(knowledgeSeparator) && StringUtils.isNotBlank(knowledgeSeparator)) {
             // 按自定义分隔符切分