mybatis xml 文件热加载实现

import org.apache.ibatis.builder.xml.XMLMapperBuilder;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.beans.BeansException;
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.stereotype.Component;
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;
@Component
public class XMLMapperReloader implements ApplicationContextAware {
    private ConfigurableApplicationContext context = null;
    private HashMap<String, Long> fileMapping = new HashMap<String, Long>();
    private Scanner scanner = null;
    private String packageSearchPath="classpath:mapper/*.xml";
    private ScheduledExecutorService service = null;
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.context = (ConfigurableApplicationContext) applicationContext;
    }
    public XMLMapperReloader(){
        service = Executors.newScheduledThreadPool(1);
        service.scheduleAtFixedRate(new Task(), 5, 5, TimeUnit.SECONDS);
    }
    class Task implements Runnable {
        @Override
        public void run() {
            try {
                scanner = new Scanner();
                scanner.refreshMapper();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    @SuppressWarnings({ "rawtypes" })
    class Scanner {
        private Resource[] mapperLocations;
        public void refreshMapper() {
            try {
                SqlSessionFactory factory = context.getBean(SqlSessionFactory.class);
                Configuration configuration = factory.getConfiguration();
                // step.1 扫描文件
                try {
                    this.scanMapperXml();
                } catch (IOException e) {
                    return;
                }
                // step.2 判断是否有文件发生了变化
                if (this.isChanged()) {
                    System.out.println("==============检测到mapper有改变, 开始刷新...===============");
                    // step.2.1 清理
                    this.removeConfig(configuration);
                    // step.2.2 重新加载
                    for (Resource configLocation : mapperLocations) {
                        try {
                            XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(configLocation.getInputStream(), configuration, configLocation.toString(), configuration.getSqlFragments());
                            xmlMapperBuilder.parse();
                        } catch (IOException e) {
                            continue;
                        }
                    }
                    System.out.println("==============mapper刷新完毕===============");
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        private void scanMapperXml() throws IOException {
            this.mapperLocations = new PathMatchingResourcePatternResolver().getResources(packageSearchPath);
        }
        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();
        }
        private boolean isChanged() throws IOException {
            boolean flag = false;
            for (Resource resource : mapperLocations) {
                String resourceName = resource.getFilename();
                boolean addFlag = !fileMapping.containsKey(resourceName);// 此为新增标识
                // 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();
                boolean modifyFlag = null != compareFrame && compareFrame.longValue() != lastFrame;// 此为修改标识
                // 新增或是修改时,存储文件
               // if(addFlag || modifyFlag) {
                    fileMapping.put(resourceName, Long.valueOf(lastFrame));// 文件内容帧值
                    flag = true;
              //  }
            }
            return flag;
        }
    }
    public String getPackageSearchPath() {
        return packageSearchPath;
    }
    public void setPackageSearchPath(String packageSearchPath) {
        this.packageSearchPath = packageSearchPath;
    }
}