分享一个修改了xml文件再也不用重启的项目mybatis-xmlreload

/**
 * 是否启动以及xml路径的配置类
 */
private MybatisXmlReloadProperties prop;
/**
 * 获取项目中初始化完成的SqlSessionFactory列表，对多数据源进行处理
 */
private List<SqlSessionFactory> sqlSessionFactories;
public MybatisXmlReload(MybatisXmlReloadProperties prop, 
        List<SqlSessionFactory> sqlSessionFactories) {
    this.prop = prop;
    this.sqlSessionFactories = sqlSessionFactories;
}

// 解析项目所有xml路径，获取xml文件在target目录中的位置
List<Resource> mapperLocationsTmp = Stream.of(
  Optional.of(prop.getMapperLocations())
  .orElse(new String[0]))
  .flatMap(location -> Stream.of(getResources(patternResolver, location)))
  .toList();

// 根据xml文件在target目录下的位置，进行路径替换找到该xml文件在resources目录下的位置
for (Resource mapperLocation : mapperLocationsTmp) {
    mapperLocations.add(mapperLocation);
    String absolutePath = mapperLocation.getFile().getAbsolutePath();
    File tmpFile = new File(absolutePath.replace(CLASS_PATH_TARGET,
      MAVEN_RESOURCES));
    if (tmpFile.exists()) {
        locationPatternSet.add(Path.of(tmpFile.getParent()));
        FileSystemResource fileSystemResource = 
          new FileSystemResource(tmpFile);
        mapperLocations.add(fileSystemResource);
    }
}

// 对resources目录的xml文件修改进行监听
List<Path> rootPaths = new ArrayList<>();
rootPaths.addAll(locationPatternSet);
DirectoryWatcher watcher = DirectoryWatcher.builder()
    .paths(rootPaths) // or use paths(directoriesToWatch)
    .listener(event -> {
        switch (event.eventType()) {
            case CREATE: /* file created */
                break;
            case MODIFY: /* file modified */
                Path modifyPath = event.path();
                String absolutePath = modifyPath.toFile().getAbsolutePath();
                logger.info("mybatis xml file has changed:" + modifyPath);
                // 执行热加载逻辑...
                break;
            case DELETE: /* file deleted */
                break;
        }
    })
    .build();
ThreadFactory threadFactory = r -> {
    Thread thread = new Thread(r);
    thread.setName("xml-reload");
    thread.setDaemon(true);
    return thread;
};
watcher.watchAsync(new ScheduledThreadPoolExecutor(1, threadFactory));

// 对多个数据源进行遍历，判断修改过的xml文件属于那个数据源
for (SqlSessionFactory sqlSessionFactory : sqlSessionFactories) {
    ...
}

// 根据 Configuration 对象获取对应的标签属性
Configuration targetConfiguration = sqlSessionFactory.getConfiguration();
Class<?> tClass = targetConfiguration.getClass(), 
  aClass = targetConfiguration.getClass();
if (targetConfiguration.getClass().getSimpleName()
                                  .equals("MybatisConfiguration")) {
    aClass = Configuration.class;
}
Set<String> loadedResources = (Set<String>) getFieldValue(
    targetConfiguration, aClass, "loadedResources");
loadedResources.clear();

Map<String, ResultMap> resultMaps = (Map<String, ResultMap>) getFieldValue(
    targetConfiguration, tClass, "resultMaps");
Map<String, XNode> sqlFragmentsMaps = (Map<String, XNode>) getFieldValue(
    targetConfiguration, tClass, "sqlFragments");
Map<String, MappedStatement> mappedStatementMaps = 
    (Map<String, MappedStatement>) getFieldValue(
        targetConfiguration, tClass, "mappedStatements");

// 遍历 resources 目录下 xml 文件列表
for (Resource mapperLocation : mapperLocations) {
    ...
}

// 判断是否是被修改过的xml文件，否则跳过
if (!absolutePath.equals(mapperLocation.getFile().getAbsolutePath())) {
    continue;
}

// 重新解析xml文件，替换Configuration对象的相对应属性
XPathParser parser = new XPathParser(mapperLocation.getInputStream(), 
    true, 
    targetConfiguration.getVariables(), 
    new XMLMapperEntityResolver());
XNode mapperXnode = parser.evalNode("/mapper");
String namespace = mapperXnode.getStringAttribute("namespace");
List<XNode> resultMapNodes = mapperXnode.evalNodes("/mapper/resultMap");
for (XNode xNode : resultMapNodes) {
    String id = 
        xNode.getStringAttribute("id", xNode.getValueBasedIdentifier());
    resultMaps.remove(namespace + "." + id);
}

List<XNode> sqlNodes = mapperXnode.evalNodes("/mapper/sql");
for (XNode sqlNode : sqlNodes) {
    String id = 
        sqlNode.getStringAttribute("id", sqlNode.getValueBasedIdentifier());
    sqlFragmentsMaps.remove(namespace + "." + id);
}

List<XNode> msNodes = mapperXnode.evalNodes("select|insert|update|delete");
for (XNode msNode : msNodes) {
    String id = 
        msNode.getStringAttribute("id", msNode.getValueBasedIdentifier());
    mappedStatementMaps.remove(namespace + "." + id);
}

// 9. 重新加载和解析被修改的 xml 文件
try {
    XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(
        mapperLocation.getInputStream(),
        targetConfiguration,
        mapperLocation.toString(), 
        targetConfiguration.getSqlFragments());
    xmlMapperBuilder.parse();
} catch (Exception e) {
    logger.error(e.getMessage(), e);
}

<dependency>
    <groupId>io.github.wayn111</groupId>
    <artifactId>mybatis-xmlreload-spring-boot-starter</artifactId>
    <version>3.0.3.m1</version>
</dependency>

<dependency>
    <groupId>io.github.wayn111</groupId>
    <artifactId>mybatis-xmlreload-spring-boot-starter</artifactId>
    <version>2.0.1.m1</version>
</dependency>

# mybatis xml文件热加载配置
mybatis-xml-reload:
  # 是否开启 xml 热更新，true开启，false不开启，默认为false
  enabled: true 
  # xml文件路径，可以填写多个，逗号分隔。
  # eg: `classpath*:mapper/**/*Mapper.xml,classpath*:other/**/*Mapper.xml`
  mapper-locations: classpath:mapper/*Mapper.xml