增加 mybatis 自动热加载插件

mybatis-plus/src/main/java/com/baomidou/mybatisplus/plugins/SqlExplainInterceptor.java

@@ -1,5 +1,4 @@
 /**
-
  * Copyright (c) 2011-2020, hubin (jobob@qq.com).
  *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
@@ -39,7 +38,7 @@ import com.baomidou.mybatisplus.exceptions.MybatisPlusException;
 
 /**
  * <p>
- * SQL 执行分析拦截器
+ * SQL 执行分析拦截器【 目前只支持 MYSQL-5.6.3 以上版本 】
  * </p>
  * 
  * @author hubin

mybatis-plus/src/main/java/com/baomidou/mybatisplus/spring/MybatisXMLMapperLoader.java

@@ -0,0 +1,472 @@
+/**
+ * Copyright (c) 2011-2020, hubin (jobob@qq.com).
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.baomidou.mybatisplus.spring;
+
+import java.io.IOException;
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.apache.ibatis.builder.xml.XMLMapperBuilder;
+import org.apache.ibatis.executor.ErrorContext;
+import org.apache.ibatis.session.Configuration;
+import org.apache.ibatis.session.SqlSessionFactory;
+import org.mybatis.spring.mapper.MapperScannerConfigurer;
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.DisposableBean;
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
+import org.springframework.core.io.support.ResourcePatternResolver;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.StopWatch;
+import org.springframework.util.StringUtils;
+
+/**
+ * <p>
+ * 切莫用于生产环境（后果自负）<br>
+ * mybatis映射文件热加载（发生变动后自动重新加载）.<br>
+ * 方便开发时使用，不用每次修改xml文件后都要去重启应用.<br>
+ * 特性：<br>
+ * 1.支持不同的数据源。<br>
+ * 2.双线程实时监控，一个用来监控全局，一个用来实时监控热点文件。（100ms）（热点文件2分钟内没续修改自动过期）<br>
+ * 3.对于CPU不给力和映射文件庞大的应用，有一定程度的性能问题。<br>
+ * </p>
+ * 
+ * @author hubin
+ * @Date 2016-08-25
+ */
+public class MybatisXMLMapperLoader implements DisposableBean, InitializingBean, ApplicationContextAware {
+
+	private ApplicationContext applicationContext;
+	private ScheduledExecutorService pool;
+
+	// 多数据源的场景使用
+	private Boolean enableAutoReload = true; // 是否启用热加载.
+	private String mapperLocations; // 指定映射配置文件
+	private MapperScannerConfigurer config;
+	private SqlSessionFactory sqlSessionFactory;
+
+	/**
+	 * 是否启用热加载.
+	 * 
+	 * @param config
+	 */
+	public void setEnableAutoReload(Boolean enableAutoReload) {
+		this.enableAutoReload = enableAutoReload;
+	}
+
+	/**
+	 * 指定映射配置文件.
+	 * 
+	 * @param config
+	 */
+	public void setMapperLocations(String mapperLocations) {
+		if (!StringUtils.isEmpty(mapperLocations)) {
+			this.mapperLocations = mapperLocations;
+		}
+	}
+
+	/**
+	 * 设置配置对象.
+	 *
+	 * @param config
+	 */
+	public void setConfig(MapperScannerConfigurer config) {
+		this.config = config;
+	}
+
+	/**
+	 * 设置数据源.
+	 *
+	 * @param sqlSessionFactory
+	 */
+	public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
+		this.sqlSessionFactory = sqlSessionFactory;
+	}
+
+	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
+		this.applicationContext = applicationContext;
+	}
+
+	public void afterPropertiesSet() throws Exception {
+
+		// 检查设置
+		if (!enableAutoReload) {
+			System.out.println("禁用：mybatis自动热加载！");
+			return;
+		} else {
+			System.out.println("启用：mybatis自动热加载");
+		}
+
+		checkProperties(); // 检查属性
+
+		// 获取mapperLocations
+		String mapperLocations = getMapperLocations();
+
+		// 初始化线程池2个（避免线程来回切换）（一个用来监控全局，一个用来实时监控热点文件.）
+		pool = Executors.newScheduledThreadPool(2);
+
+		// 配置扫描器.
+		final AutoReloadScanner scaner = new AutoReloadScanner(mapperLocations);
+		scaner.start();
+
+		// 扫描全部（2s一次）
+		pool.scheduleAtFixedRate(new Runnable() {
+			public void run() {
+				scaner.scanAllFileChange();
+			}
+		}, 2, 2, TimeUnit.SECONDS);
+
+		// 扫描热点文件（100ms一次，监控更为频繁）
+		pool.scheduleAtFixedRate(new Runnable() {
+			public void run() {
+				scaner.scanHotspotFileChange();
+			}
+		}, 2, 100, TimeUnit.MILLISECONDS);
+
+		System.out.println("启动mybatis自动热加载");
+	}
+
+	/**
+	 * 获取配置文件路径（mapperLocations）.
+	 *
+	 * @return
+	 * @throws NoSuchFieldException
+	 * @throws IllegalAccessException
+	 * @throws Exception
+	 */
+	private String getMapperLocations() throws NoSuchFieldException, IllegalAccessException, Exception {
+
+		// 优先使用mapperLocations
+		if (mapperLocations != null) {
+			return mapperLocations;
+		}
+
+		// 从MapperScannerConfigurer中获取.
+		if (config != null) {
+			Field field = config.getClass().getDeclaredField("basePackage");
+			field.setAccessible(true);
+			return (String) field.get(config);
+		}
+
+		// 根本就获取不到 org.mybatis.spring.SqlSessionFactoryBean
+		// spring的org.springframework.beans.factory.FactoryBean 将其封装成为了一个
+		// org.apache.ibatis.session.defaults.DefaultSqlSessionFactory
+		// 牛逼的spring
+		// if(sqlSessionFactory != null){
+		// Field field =
+		// sqlSessionFactory.getClass().getDeclaredField("mapperLocations");
+		// field.setAccessible(true);
+		// Resource[] mapperLocations = (Resource[])
+		// field.get(sqlSessionFactory);
+		// StringBuilder sb = new StringBuilder();
+		// for(Resource r : mapperLocations){
+		// String n = r.getURL().toString();
+		// sb.append(n).append("\n");
+		// }
+		// return sb.toString();
+		// }
+		throw new RuntimeException("获取mapperLocations失败！");
+	}
+
+	/**
+	 * 检查属性，如果没有设置，直接初始化成默认的方式.
+	 */
+	private void checkProperties() {
+		// 如果没有指定数据源，直接使用默认的方式获取数据源
+		if (sqlSessionFactory == null) {
+			try {
+				sqlSessionFactory = applicationContext.getBean(SqlSessionFactory.class);
+			} catch (BeansException e) {
+				throw new RuntimeException("获取数据源失败！", e);
+			}
+		}
+
+		// 如果没有指定配置文件，使用默认的方式获取配置文件
+		if (config == null && mapperLocations == null) {
+			try {
+				config = applicationContext.getBean(MapperScannerConfigurer.class);
+			} catch (BeansException e) {
+				System.err.println("获取配置文件失败！");
+			}
+		}
+
+		if (config == null && mapperLocations == null) {
+			throw new RuntimeException("设置配置mapperLocations失败！，请设置好配置属性，否则自动热加载无法起作用!");
+		}
+	}
+
+	public void destroy() throws Exception {
+		if (pool == null) {
+			return;
+		}
+		pool.shutdown(); // 是否线程池资源
+	}
+
+	/**
+	 * 自动重载扫描器的具体实现
+	 *
+	 *
+	 * @author thomas
+	 * @date Mar 31, 2016 6:59:34 PM
+	 *
+	 */
+	class AutoReloadScanner {
+
+		static final String XML_RESOURCE_PATTERN = "**/*.xml";
+		static final String CLASSPATH_ALL_URL_PREFIX = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX;
+
+		static final int expireTimes = 600 * 2; // 2分钟内没有继续修改，变成非热点文件.不进行实时监控.
+
+		// 需要扫描的包
+		String[] basePackages;
+
+		ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
+
+		// 所有文件
+		Map<String, String> files = new ConcurrentHashMap<String, String>();
+
+		// 热点文件.
+		Map<String, AtomicInteger> hotspot = new ConcurrentHashMap<String, AtomicInteger>();
+
+		public AutoReloadScanner(String basePackage) {
+			basePackages = StringUtils.tokenizeToStringArray(basePackage,
+					ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
+		}
+
+		/**
+		 * 只扫描热点文件改变.（热点文件失效：连续600个扫描周期内（1分钟）没有改变）
+		 */
+		public void scanHotspotFileChange() {
+
+			// 如果热点文件为空，立即返回.
+			if (hotspot.isEmpty()) {
+				return;
+			}
+
+			List<String> list = new ArrayList<String>();
+			for (Map.Entry<String, AtomicInteger> e : hotspot.entrySet()) {
+				String url = e.getKey();
+				AtomicInteger counter = e.getValue();
+				if (counter.incrementAndGet() >= expireTimes) {
+					// 计数器自增，判断是否超过指定的过期次数
+					list.add(url);
+				}
+				if (hasChange(url, files.get(url))) {
+					reload(url); // 变化，调用重新加载方法
+					counter.set(0); // 计数器清零
+				}
+			}
+
+			// 移除过期的热点文件
+			if (!list.isEmpty()) {
+				// System.out.println("移除过期的热点文件：list=" + list);
+				for (String s : list) {
+					hotspot.remove(s);
+				}
+			}
+		}
+
+		/**
+		 * 重新加载文件.
+		 *
+		 * @param url
+		 */
+		private void reload(String url) {
+			reloadAll(); // 必须加载所有文件，否则其它文件由于没有加载会导致找不到对应的语句异常（暂时先这样吧）
+		}
+
+		/**
+		 * 重新加载所有文件.
+		 */
+		private void reloadAll() {
+			StopWatch sw = new StopWatch("mybatis mapper auto reload");
+			sw.start();
+			Configuration configuration = getConfiguration();
+			for (Map.Entry<String, String> entry : files.entrySet()) {
+				String location = entry.getKey();
+				Resource r = resourcePatternResolver.getResource(location);
+				try {
+					XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(r.getInputStream(), configuration,
+							r.toString(), configuration.getSqlFragments());
+					xmlMapperBuilder.parse();
+				} catch (Exception e) {
+					throw new RuntimeException("Failed to parse mapping resource: '" + r + "'", e);
+				} finally {
+					ErrorContext.instance().reset();
+				}
+			}
+			sw.stop();
+			// System.out.println("重新加载mybatis映射文件完成.");
+			System.out.println(sw.shortSummary());
+		}
+
+		/**
+		 * 扫描所有文件改变.
+		 */
+		public void scanAllFileChange() {
+			for (Map.Entry<String, String> entry : files.entrySet()) {
+				String url = entry.getKey();
+				if (hasChange(url, entry.getValue())) {
+					// 变化，判断是否在热点文件中，如果存在，直接忽略，如果不存在，触发重新加载
+					if (!hotspot.containsKey(url)) {
+						// 添加到热点文件，并且触发重新加载
+						hotspot.put(url, new AtomicInteger(0));
+						reload(url);
+					}
+				}
+			}
+		}
+
+		/**
+		 * 判断文件是否变化.
+		 *
+		 * @param url
+		 * @param tag
+		 * @return
+		 */
+		private boolean hasChange(String url, String tag) {
+			Resource r = resourcePatternResolver.getResource(url);
+			String newTag = getTag(r);
+			// 之前的标记和最新的标记不一致，说明文件修改了！
+			if (!tag.equals(newTag)) {
+				files.put(url, newTag); // 更新标记
+				return true;
+			}
+			return false;
+		}
+
+		/**
+		 * 获得文件的标记.
+		 * 
+		 * @param r
+		 * @return
+		 */
+		private String getTag(Resource r) {
+			try {
+				StringBuilder sb = new StringBuilder();
+				sb.append(r.contentLength());
+				sb.append(r.lastModified());
+				return sb.toString();
+			} catch (IOException e) {
+				throw new RuntimeException("获取文件标记信息失败！r=" + r, e);
+			}
+		}
+
+		/**
+		 * 开启扫描服务
+		 */
+		public void start() {
+			try {
+				for (String basePackage : basePackages) {
+					Resource[] resources = getResource(basePackage);
+					if (resources != null) {
+						for (Resource r : resources) {
+							String tag = getTag(r);
+							files.put(r.getURL().toString(), tag);
+						}
+					}
+				}
+			} catch (Exception e) {
+				throw new RuntimeException("初始化扫描服务失败！", e);
+			}
+		}
+
+		/**
+		 * 获取xml文件资源.
+		 *
+		 * @param basePackage
+		 * @param pattern
+		 * @return
+		 * @throws IOException
+		 */
+		public Resource[] getResource(String basePackage) {
+			try {
+				if (!basePackage.startsWith(CLASSPATH_ALL_URL_PREFIX)) {
+					basePackage = CLASSPATH_ALL_URL_PREFIX
+							+ ClassUtils.convertClassNameToResourcePath(
+									applicationContext.getEnvironment().resolveRequiredPlaceholders(basePackage))
+							+ "/" + XML_RESOURCE_PATTERN;
+				}
+				Resource[] resources = resourcePatternResolver.getResources(basePackage);
+				return resources;
+			} catch (Exception e) {
+				throw new RuntimeException("获取xml文件资源失败！basePackage=" + basePackage, e);
+			}
+		}
+
+		/**
+		 * 获取配置信息，必须每次都重新获取，否则重新加载xml不起作用.
+		 * 
+		 * @return
+		 */
+		private Configuration getConfiguration() {
+			Configuration configuration = sqlSessionFactory.getConfiguration();
+			removeConfig(configuration);
+			return configuration;
+		}
+
+		/**
+		 * 删除不必要的配置项.
+		 * 
+		 * @param configuration
+		 * @throws Exception
+		 */
+		private void removeConfig(Configuration configuration) {
+			try {
+				Class<?> classConfig = configuration.getClass();
+				clearMap(classConfig, configuration, "mappedStatements");
+				clearMap(classConfig, configuration, "caches");
+				clearMap(classConfig, configuration, "resultMaps");
+				clearMap(classConfig, configuration, "parameterMaps");
+				clearMap(classConfig, configuration, "keyGenerators");
+				clearMap(classConfig, configuration, "sqlFragments");
+				clearSet(classConfig, configuration, "loadedResources");
+			} catch (Exception e) {
+				e.printStackTrace();
+			}
+		}
+
+		@SuppressWarnings("rawtypes")
+		private void clearMap(Class<?> classConfig, Configuration configuration, String fieldName) throws Exception {
+			Field field = classConfig.getDeclaredField(fieldName);
+			field.setAccessible(true);
+			Map mapConfig = (Map) field.get(configuration);
+			mapConfig.clear();
+		}
+
+		@SuppressWarnings("rawtypes")
+		private void clearSet(Class<?> classConfig, Configuration configuration, String fieldName) throws Exception {
+			Field field = classConfig.getDeclaredField(fieldName);
+			field.setAccessible(true);
+			Set setConfig = (Set) field.get(configuration);
+			setConfig.clear();
+		}
+
+	}
+
+}

mybatis-plus/src/test/resources/wiki/spring-config.md

@@ -41,9 +41,20 @@
 <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
 	<property name="basePackage" value="xxx.mapper" />
 </bean>
+
+<!-- MyBatis 自动热加载 -->
+<bean class="com.baomidou.mybatisplus.spring.MybatisXMLMapperLoader" >
+    <!-- 设置是否启用: 默认启用 -->
+    <property name="enableAutoReload" value="true" />
+    <!-- 设置sqlSessionFactory -->
+    <property name="sqlSessionFactory" ref="sqlSessionFactory" />
+    <!-- 设置映射文件地址 -->
+    <property name="mapperLocations" value="classpath*:xx/mapper/*.xml" />
+</bean>
 ```
 
 
+
 > mybatis-config.xml
 
 ```