Mybatis 热部署 自动更新mapper映射文件

######################  myBatis xml mapper hot swap config start  ######################
#扫描周期，默认5秒,单位秒
mybatis.mapperRefresher.periodSeconds=1
#初始化完成,延迟扫描时间，默认5秒,单位秒,
mybatis.mapperRefresher.initialDelaySeconds=30
#是否启用mybatis热部署 默认:false
mybatis.mapperRefresher.enabled=true
######################  myBatis xml mapper hot swap config end  ######################

----------------------------------------------------

package zh.persistence.utils;

import java.io.IOException;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import com.sibu.common.util.ExceptionUtil;
import lombok.extern.slf4j.Slf4j;
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.SqlSessionFactoryBean;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.NestedIOException;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.stereotype.Component;
import org.springframework.util.ClassUtils;

/**
* @author 陈志杭
* @contact 279397942@qq.com
* @date 2016-12-13 16:00
* @description MyBatis mapper xml 配置文件热加载
*/
@Component
@Slf4j
public class MyBatisMapperRefresher implements DisposableBean, InitializingBean, ApplicationContextAware {
/**
* 扫描周期，单位秒
*/
@Value("${mybatis.mapperRefresher.periodSeconds:5}")
private int periodSeconds = 5;
/**
* 初始化完成,延迟扫描时间，单位秒
*/
@Value("${mybatis.mapperRefresher.initialDelaySeconds:5}")
private int initialDelay = 5;
/**
* 是否启用
*/
@Value("${mybatis.mapperRefresher.enabled:false}")
private boolean enabled = false;
private ConfigurableApplicationContext context = null;
private transient Resource[] basePackage = null;
private HashMap<String, String> fileMapping = new HashMap<String, String>();
private Scanner scanner = null;
private ScheduledExecutorService service = null;

@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.context = (ConfigurableApplicationContext) applicationContext;

}

@Override
public void afterPropertiesSet() throws Exception {
if (enabled == false) {
log.info("MyBatisMapperRefresher is Disabled");
return;
}

try {
service = Executors.newScheduledThreadPool(1);
// 获取xml所在包
SqlSessionFactoryBean config = context.getBean(SqlSessionFactoryBean.class);
Field field = config.getClass().getDeclaredField("mapperLocations");
field.setAccessible(true);
basePackage = (Resource[]) field.get(config);
// 触发文件监听事件
scanner = new Scanner();
scanner.scan();
service.scheduleAtFixedRate(new Task(), MyBatisMapperRefresher.this.initialDelay, MyBatisMapperRefresher.this.periodSeconds, TimeUnit.SECONDS);

} catch (Exception e1) {
log.error("can not starter Mybatis xml refresher,exception:{}", ExceptionUtil.getAsString(e1));
}

}

class Task implements Runnable {
@Override
public void run() {
try {
if (scanner.isChanged()) {
scanner.reloadXML();
}
} catch (Exception ex) {
log.error("MyBatisMapperRefresher,exception:{}", ExceptionUtil.getAsString(ex));
}
}
}

@SuppressWarnings({"rawtypes"})
class Scanner {
private Resource[] mapperXmlFiles;

public Scanner() {
mapperXmlFiles = MyBatisMapperRefresher.this.basePackage;
}

public void reloadXML() throws Exception {
SqlSessionFactory factory = context.getBean(SqlSessionFactory.class);
Configuration configuration = factory.getConfiguration();
// 移除加载项
removeConfig(configuration);
// 重新扫描加载

Resource[] resources = mapperXmlFiles;
if (resources != null) {
for (int i = 0; i < resources.length; i++) {
if (resources[i] == null) {
continue;
}
try {
XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(resources[i].getInputStream(),
configuration, resources[i].toString(), configuration.getSqlFragments());
xmlMapperBuilder.parse();
} catch (Exception e) {
log.error("please fixup to repeat hot swap,failed to parse mapping resource: {},exception:{}", resources[i].getFilename(), ExceptionUtil.getAsString(e));
break;
} finally {
ErrorContext.instance().reset();
}
}
}
}

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");

}

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();
}

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();
}

public void scan() throws IOException {
if (!fileMapping.isEmpty()) {
return;
}

Resource[] resources = mapperXmlFiles;
if (resources != null) {
for (int i = 0; i < resources.length; i++) {
String multi_key = getValue(resources[i]);
String fileName = resources[i].getFilename();
fileMapping.put(fileName, multi_key);
log.info("monitor Mybatis mapper file:{}",  resources[i].getFile().getAbsolutePath());
}
}

}

private String getValue(Resource resource) throws IOException {
String contentLength = String.valueOf((resource.contentLength()));
String lastModified = String.valueOf((resource.lastModified()));
return new StringBuilder(contentLength).append(lastModified).toString();
}

public boolean isChanged() throws IOException {
boolean isChanged = false;

Resource[] resources = mapperXmlFiles;
if (resources != null) {
for (int i = 0; i < resources.length; i++) {
String name = resources[i].getFilename();
String value = fileMapping.get(name);
String multi_key = getValue(resources[i]);
if (!multi_key.equals(value)) {
isChanged = true;
fileMapping.put(name, multi_key);
log.info("reload Mybatis mapper file:{}", resources[i].getFile().getAbsolutePath());
}
}
}

return isChanged;
}

}

@Override
public void destroy() throws Exception {
if (service != null) {
service.shutdownNow();
}
}

}