为什么80%的码农都做不了架构师？>>> 
这个是在@歇蹩虎子 （http://www.oschina.net/code/snippet_1018034_26472）提供的自动加载的基础上改进的；
主要是添加了注解方式的自动加载
import java.io.File;
import java.io.IOException;
import java.lang.reflect.Field;
import java.net.URL;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import org.apache.ibatis.binding.MapperRegistry;
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.apache.log4j.Logger;
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.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.NestedIOException;
import org.springframework.core.io.Resource;
/**
*
*
*
*
* @author 吕兵峰 2014-2-19 上午11:56:47
* @version V1.0
* @modificationHistory 如有逻辑或功能性重大变更记录，请修改一下以下内容
* @modify by user: {修改人} 2014-2-19
* @modify by reason:{方法名}:{原因}
*/
public class MyMapperLoader implements DisposableBean, InitializingBean,
ApplicationContextAware {
private Logger logger = Logger.getLogger(MyMapperLoader.class);
private ConfigurableApplicationContext context = null;
private HashMap fileMapping = new HashMap();
private Scanner scanner = null;
private ScheduledExecutorService service = null;
private Resource[] resources = null;
private File[] mapperFiles;
private Collection> mappers;
@Override
public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
this.context = (ConfigurableApplicationContext) applicationContext;
}
@Override
public void afterPropertiesSet() throws Exception {
try {
service = Executors.newScheduledThreadPool(1);
// 获取xml
SqlSessionFactoryBean sessionFactoryBean = context
.getBean(SqlSessionFactoryBean.class);
Field field = sessionFactoryBean.getClass().getDeclaredField(
"mapperLocations");
field.setAccessible(true);
resources = (Resource[]) field.get(sessionFactoryBean);
//获取mapper的class
SqlSessionFactory factory = context
.getBean(SqlSessionFactory.class);
Configuration configuration = factory.getConfiguration();
mappers = configuration.getMapperRegistry().getMappers();
mapperFiles = new File[mappers.size()];
Iterator> iterator = mappers.iterator();
int i = 0;
while (iterator.hasNext()) {
Class class1 = (Class) iterator.next();
URL url = new URL(class1.getResource("")
+ class1.getSimpleName() + ".class");
mapperFiles[i++] = new File(url.getFile());
}
// 触发文件监听事件
scanner = new Scanner();
scanner.scan();
service.scheduleAtFixedRate(new Task(), 5, 5, TimeUnit.SECONDS);
} catch (Exception e1) {
e1.printStackTrace();
}
}
class Task implements Runnable {
@Override
public void run() {
try {
if (scanner.isChanged()) {
logger.debug("文件改变,重新加载.");
System.out.println("");
scanner.reload();
logger.debug("加载完毕.");
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
@SuppressWarnings({ "rawtypes" })
class Scanner {
public void reload() 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xml
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) {
throw new NestedIOException(
"Failed to parse mapping resource: '"
+ resources[i] + "'", e);
} finally {
ErrorContext.instance().reset();
}
}
}
// 重新扫描加载class
Field f = Configuration.class.getDeclaredField("mapperRegistry");
f.setAccessible(true);
f.set(configuration, new MapperRegistry(configuration));
Iterator> iterator = mappers.iterator();
while (iterator.hasNext()) {
Class class1 = (Class) iterator.next();
configuration.addMapper(class1);
}
}
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;
}
if (resources != null) {
for (int i = 0; i < resources.length; i++) {
String multi_key = getValue(resources[i]);
fileMapping.put(resources[i].getFilename(), multi_key);
}
}
if (mapperFiles != null) {
for (int i = 0; i < mapperFiles.length; i++) {
fileMapping.put(mapperFiles[i].getAbsolutePath(),
mapperFiles[i].lastModified() + "");
}
}
}
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;
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);
}
}
}
if (mapperFiles != null) {
for (int i = 0; i < mapperFiles.length; i++) {
String name = mapperFiles[i].getAbsolutePath();
String preValue = fileMapping.get(name);
String curValue = mapperFiles[i].lastModified() + "";
if (!curValue.equals(preValue)) {
isChanged = true;
fileMapping.put(name, curValue);
}
}
}
return isChanged;
}
}
@Override
public void destroy() throws Exception {
if (service != null) {
service.shutdownNow();
}
}
}