其他
2020年10月19日大约 4 分钟
其他
刷新mapper
package com.iris.egrant.mybatis;
import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.core.MybatisMapperRegistry;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.ibatis.builder.xml.XMLMapperBuilder;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.mapper.MapperFactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.core.io.Resource;
import org.springframework.web.context.ConfigurableWebApplicationContext;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.WebApplicationContext;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.*;
/**
* 刷新Mybatis的mapper缓存，重新加载sql语句，避免修改sql之后需要重启之后才能观察效果，提高开发效率。<br/>
*
* <p>该方法采用定时器执行缓存刷新的逻辑，<strong>refreshMapper</strong>为核心方法。</p>
*<br/>
*<p>主要逻辑：</p>
* <ol>
* <li>Bean初始化时加载所有的mapper文件</li>
* <li>Spring上下文初始化结束之后，创建后台任务执行<strong>refreshMapper</strong><br/>
* 创建后台任务必须满足以下两个条件：
* <p>enable设置为true，该值默认为false。开发人员可在需要开启的时，将其设置为true</p>
* <p>只在开发环境运行</p>
* </li>
* </ol>
* @author zengsl
* @version V1.0
* @date 2020/10/15 10:30 上午
*/
public class RefreshMapperCache implements ApplicationListener<ContextRefreshedEvent> , InitializingBean {
private final Log log = LogFactory.getLog(getClass());
private SqlSessionFactory sqlSessionFactory;
/**
* 所有mapper文件
*/
private Resource[] mapperLocations;
/**
* 定时器启动标识，默认为不启动，如需启动请在配置文件中设置为true
*/
private boolean enable = false;
/**
* 可运行环境<br/>
* 开发与linux开发环境
*/
public final static List<String> EXECUTE_ENVIRONMENT = Arrays.asList("development", "linuxdev");
/**
* 保存最新的文件
*/
private final HashMap<String, Long> fileMapping = new HashMap<>();
/**
* 当前执行状态
*/
private ExecuteState currentExecuteState = ExecuteState.STOP;
@Override
public void afterPropertiesSet() throws Exception {
// bean初始化时，先将所有的mapper文件加载至fileMapping
loadMapper();
}
@Override
public void onApplicationEvent(ContextRefreshedEvent event) {
if (event.getApplicationContext().getParent() != null) {
log.info("不触发事件");
return;
}
if(currentExecuteState == ExecuteState.RUNNING) {
log.info("任务已执行，不再重复执行");
return;
}
initRefreshTask();
currentExecuteState = ExecuteState.RUNNING;
}
/**
* 初始化刷新任务
*
* @date 2020/10/16 4:43 下午
*/
protected void initRefreshTask() {
if (!enable) {
return;
}
String runEnv = System.getProperty("spring.profiles.active", "run");
// 判断是否可运行环境
if (!EXECUTE_ENVIRONMENT.contains(runEnv)) {
return;
}
try {
new Timer(true).schedule(new TimerTask() {
@Override
public void run() {
refreshMapper();
}
}, 10 * 1000, 5 * 1000);
} catch (Exception e) {
log.error("定时器启动失败", e);
}
}
/**
* 刷新所有mapper配置的核心方法
*
* @author zengsl
* @date 2020/10/16 5:17 下午
*/
@SuppressWarnings("rawtypes")
public void refreshMapper() {
try {
Configuration configuration = this.sqlSessionFactory.getConfiguration();
// 判断是否有文件发生了变化
if (!this.isChanged()) {
return;
}
// 清理配置
this.removeConfig(configuration);
// 重新加载配置文件
for (Resource configLocation : mapperLocations) {
try {
XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(configLocation.getInputStream(), configuration, configLocation.toString(), configuration.getSqlFragments());
xmlMapperBuilder.parse();
log.info("mapper文件[" + configLocation.getFilename() + "]缓存加载成功");
} catch (IOException e) {
log.error("mapper文件[" + configLocation.getFilename() + "]不存在或内容格式不对", e);
}
}
WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext();
ConfigurableWebApplicationContext wac = (ConfigurableWebApplicationContext) webApplicationContext;
assert wac != null;
// 重新初始化MapperFactoryBean
Map<String, MapperFactoryBean> beanMaps = wac.getBeansOfType(MapperFactoryBean.class);
for (Map.Entry<String, MapperFactoryBean> beanMap : beanMaps.entrySet()) {
MapperFactoryBean mapperFactoryBean = beanMap.getValue();
mapperFactoryBean.afterPropertiesSet();
}
log.info("****************刷新缓存结束");
} catch (Exception e) {
log.error("****************刷新缓存异常： ", e);
}
}
/**
* 加载所有mapper配置
*
* @author zengsl
* @date 2020/10/16 5:16 下午
*/
private void loadMapper() throws IOException {
for (Resource resource : mapperLocations) {
String resourceName = resource.getFilename();
log.info("resourceName == " + resourceName + ", path = " + resource.getURL().getPath());
long lastFrame = resource.contentLength() + resource.lastModified();
fileMapping.put(resourceName, lastFrame);
}
}
/**
* 判断文件是否发生了变化
*
* @return true 变化 false 无变化
* @throws IOException 配置文件加载错误
*/
private boolean isChanged() throws IOException {
boolean flag = false;
log.info("***************************获取文件名 开始************************************");
for (Resource resource : mapperLocations) {
String resourceName = resource.getFilename();
log.info("resourceName == " + resourceName + ", path = " + resource.getURL().getPath());
// 此为新增标识
boolean addFlag = !fileMapping.containsKey(resourceName);
// 修改文件:判断文件内容是否有变化
Long compareFrame = fileMapping.get(resourceName);
long lastFrame = resource.contentLength() + resource.lastModified();
// 此为修改标识
boolean modifyFlag = null != compareFrame && compareFrame != lastFrame;
if (addFlag) {
log.info("新增了：===" + resourceName);
}
if (modifyFlag) {
log.info("修改了：===" + resourceName);
}
// 新增或是修改时,存储文件
if (addFlag || modifyFlag) {
// 文件内容帧值
fileMapping.put(resourceName, lastFrame);
flag = true;
}
}
log.info("***************************获取文件名 结束************************************");
return flag;
}
/**
* 清空Configuration中几个重要的缓存
*
* @param configuration mybatis配置对象，如果使用的是mybatis-plus该对象可能是继承了mybatis配置对象的一个对象
* @throws Exception 反射清除缓存对象出错。比如：找不到定义的属性
*/
private void removeConfig(Configuration configuration) throws Exception {
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");
// 清理mapper接口缓存
clearRegistry(classConfig, configuration);
if (configuration instanceof MybatisConfiguration) {
((MybatisConfiguration) configuration).getGlobalConfig().getMapperRegistryCache().clear();
}
}
@SuppressWarnings("rawtypes")
private void clearRegistry(Class<?> classConfig, Configuration configuration) throws Exception {
Field fieldRegistry = classConfig.getDeclaredField("mybatisMapperRegistry");
fieldRegistry.setAccessible(true);
MybatisMapperRegistry mybatisMapperRegistry = (MybatisMapperRegistry) fieldRegistry.get(configuration);
Class<?> registryConfig = mybatisMapperRegistry.getClass();
Field fieldKnownMappers = registryConfig.getDeclaredField("knownMappers");
fieldKnownMappers.setAccessible(true);
Map mapConfig = (Map) fieldKnownMappers.get(mybatisMapperRegistry);
mapConfig.clear();
}
@SuppressWarnings("rawtypes")
private void clearMap(Class<?> classConfig, Configuration configuration, String fieldName) throws Exception {
Field field;
try {
field = classConfig.getDeclaredField(fieldName);
} catch (NoSuchFieldException e) {
field = classConfig.getSuperclass().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;
try {
field = classConfig.getDeclaredField(fieldName);
} catch (NoSuchFieldException e) {
field = classConfig.getSuperclass().getDeclaredField(fieldName);
}
field.setAccessible(true);
Set setConfig = (Set) field.get(configuration);
setConfig.clear();
}
public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
this.sqlSessionFactory = sqlSessionFactory;
}
public void setMapperLocations(Resource[] mapperLocations) {
this.mapperLocations = mapperLocations;
}
public void setEnable(boolean enable) {
this.enable = enable;
}
/**
* 执行状态
* @date 2020/10/16 4:48 下午
*/
private enum ExecuteState {
/**
* 运行中
*/
RUNNING,
/**
* 停止状态
*/
STOP
}
}