关于MyBatis中Mapper XML热加载优化

package com.bzd.core.mybatis;



import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

import lombok.SneakyThrows;
import org.apache.commons.lang3.StringUtils;
import org.apache.ibatis.builder.xml.XMLMapperBuilder;
import org.apache.ibatis.executor.ErrorContext;
import org.apache.ibatis.session.Configuration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.NestedIOException;
import org.springframework.core.io.Resource;
import com.Google.common.collect.Sets;

public class MapperRefresh implements java.lang.Runnable {

    public static Logger log = LoggerFactory.getLogger(MapperRefresh.class);
    private static String filename = "mybatis-refresh.properties";
    private static Properties prop = new Properties();

    private static boolean enabled;         // 是否启用Mapper刷新线程功能
    private static boolean refresh;         // 刷新启用后，是否启动了刷新线程

    private Set<String> location;         // Mapper实际资源路径

    private Resource[] mapperLocations;     // Mapper资源路径
    private Configuration configuration;        // MyBatis配置对象

    private Long beforeTime = 0L;           // 上一次刷新时间
    private static int delaySeconds;        // 延迟刷新秒数
    private static int sleepSeconds;        // 休眠时间
    private static String mappingPath;      // xml文件夹匹配字符串，需要根据需要修改
    static {

//        try {
//            prop.load(MapperRefresh.class.getResourceAsStream(filename));
//        } catch (Exception e) {
//            e.printStackTrace();
//            System.out.println("Load mybatis-refresh “"+filename+"” file error.");
//        }


        URL url = MapperRefresh.class.getClassLoader().getResource(filename);
        InputStream is;
        try {
            is = url.openStream();
            if (is == null) {
                log.warn("applicationConfig.properties not found.");
            } else {
                prop.load(is);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        String value = getPropString("enabled");
        System.out.println(value);
        enabled = "true".equalsIgnoreCase(value);

        delaySeconds = getPropInt("delaySeconds");
        sleepSeconds = getPropInt("sleepSeconds");
        //mappingPath = getPropString("mappingPath");

        delaySeconds = delaySeconds == 0 ? 50 : delaySeconds;
        sleepSeconds = sleepSeconds == 0 ? 3 : sleepSeconds;
        mappingPath = StringUtils.isBlank(mappingPath) ? "mappings" : mappingPath;

        log.debug("[enabled] " + enabled);
        log.debug("[delaySeconds] " + delaySeconds);
        log.debug("[sleepSeconds] " + sleepSeconds);
        log.debug("[mappingPath] " + mappingPath);
    }

    public static boolean isRefresh() {
        return refresh;
    }

    public MapperRefresh(Resource[] mapperLocations, Configuration configuration) {
        this.mapperLocations = mapperLocations;
        this.configuration = configuration;
    }

    @Override
    public void run() {

        beforeTime = System.currentTimeMillis();

        log.debug("[location] " + location);
        log.debug("[configuration] " + configuration);

        if (enabled) {
            // 启动刷新线程
            final MapperRefresh runnable = this;
            new Thread(new java.lang.Runnable() {
                @SneakyThrows
                @Override
                public void run() {

                    

                    try {
                        Thread.sleep(delaySeconds * 1000);
                    } catch (InterruptedException e2) {
                        e2.printStackTrace();
                    }
                    refresh = true;

                    System.out.println("========= Enabled refresh mybatis mapper =========");

                    while (true) {
                        try {
                            log.info("start refresh");
                            List<Resource> res = getModifyResource(mapperLocations,beforeTime);
                            if(res.size()>0)
                                runnable.refresh(res);
                            // 如果刷新了文件，则修改刷新时间，否则不修改
                            beforeTime = System.currentTimeMillis();
                            log.info("end refresh("+res.size()+")");
                        } catch (Exception e1) {
                            e1.printStackTrace();
                        }
                        try {
                            Thread.sleep(sleepSeconds * 1000);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }

                    }
                }
            }, "MyBatis-Mapper-Refresh").start();
        }
    }


    private List<Resource> getModifyResource(Resource[] mapperLocations,long time){

        List<Resource> resources = new ArrayList<>();
        for (int i = 0; i < mapperLocations.length; i++) {
            try {
                if(isModify(mapperLocations[i],time))
                    resources.add(mapperLocations[i]);
            } catch (IOException e) {
                throw new RuntimeException("读取mapper文件异常",e);
            }
        }
        return resources;
    }

    private boolean isModify(Resource resource,long time) throws IOException {
        if (resource.lastModified() > time) {
            return true;
        }
        return false;
    }

    
    @SuppressWarnings({ "rawtypes", "unchecked" })
    private void refresh(List<Resource> mapperLocations) throws Exception {

        // 获取需要刷新的Mapper文件列表
        

        for (int i = 0; i < mapperLocations.size(); i++) {

            Resource resource = mapperLocations.get(i);
            InputStream inputStream = resource.getInputStream();
            System.out.println("refreshed : "+resource.getDescription());
            //这个是mybatis 加载的资源标识,没有绝对标准
            String resourcePath = resource.getDescription();
            try {

                clearMybatis(resourcePath);

                //重新编译加载资源文件。
                XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(inputStream, configuration,
                        resourcePath, configuration.getsqlFragments());
                xmlMapperBuilder.parse();
            } catch (Exception e) {
                throw new NestedIOException("Failed to parse mapping resource: '" + resourcePath + "'", e);
            } finally {
                ErrorContext.instance().reset();
            }
//            System.out.println("Refresh file: " + mappingPath + StringUtils.substringAfterLast(fileList.get(i).getAbsolutePath(), mappingPath));
            
        }


    }


    private void clearMybatis(String resource) throws NoSuchFieldException, IllegalAccessException {
        // 清理原有资源，更新为自己的StrictMap方便，增量重新加载
        String[] mapFieldNames = new String[]{
                "mappedStatements", "caches",
                "resultMaps", "parameterMaps",
                "keyGenerators", "sqlFragments"
        };
        for (String fieldName : mapFieldNames){
            Field field = configuration.getClass().getDeclaredField(fieldName);
            field.setAccessible(true);
            Map map = ((Map)field.get(configuration));
            if (!(map instanceof StrictMap)){
                Map newMap = new StrictMap(StringUtils.capitalize(fieldName) + "collection");
                for (Object key : map.keySet()){
                    try {
                        newMap.put(key, map.get(key));
                    }catch(IllegalArgumentException ex){
                        newMap.put(key, ex.getMessage());
                    }
                }
                field.set(configuration, newMap);
            }
        }

        // 清理已加载的资源标识，方便让它重新加载。
        Field loadedResourcesField = configuration.getClass().getDeclaredField("loadedResources");
        loadedResourcesField.setAccessible(true);
        Set loadedResourcesSet = ((Set)loadedResourcesField.get(configuration));
        loadedResourcesSet.remove(resource);
    }

    
    private List<File> getRefreshFile(File dir, Long beforeTime) {
        List<File> fileList = new ArrayList<File>();

        File[] files = dir.listFiles();
        if (files != null) {
            for (int i = 0; i < files.length; i++) {
                File file = files[i];
                if (file.isDirectory()) {
                    fileList.addAll(this.getRefreshFile(file, beforeTime));
                } else if (file.isFile()) {
                    if (this.checkFile(file, beforeTime)) {
                        fileList.add(file);
                    }
                } else {
                    System.out.println("Error file." + file.getName());
                }
            }
        }
        return fileList;
    }


    
    private boolean checkFile(File file, Long beforeTime) {
        if (file.lastModified() > beforeTime) {
            return true;
        }
        return false;
    }

    
    private static int getPropInt(String key) {
        int i = 0;
        try {
            i = Integer.parseInt(getPropString(key));
        } catch (Exception e) {
        }
        return i;
    }

    
    private static String getPropString(String key) {
        return prop == null ? null : prop.getProperty(key).trim();
    }

    
    public static class StrictMap<V> extends HashMap<String, V> {

        private static final long serialVersionUID = -4950446264854982944L;
        private String name;

        public StrictMap(String name, int initialCapacity, float loadFactor) {
            super(initialCapacity, loadFactor);
            this.name = name;
        }

        public StrictMap(String name, int initialCapacity) {
            super(initialCapacity);
            this.name = name;
        }

        public StrictMap(String name) {
            super();
            this.name = name;
        }

        public StrictMap(String name, Map<String, ? extends V> m) {
            super(m);
            this.name = name;
        }

        @SuppressWarnings("unchecked")
        public V put(String key, V value) {
            // ThinkGem 如果现在状态为刷新，则刷新(先删除后添加)
            if (MapperRefresh.isRefresh()) {
                remove(key);
//                MapperRefresh.log.debug("refresh key:" + key.substring(key.lastIndexOf(".") + 1));
            }
            // ThinkGem end
            if (containsKey(key)) {
                throw new IllegalArgumentException(name + " already contains value for " + key);
            }
            if (key.contains(".")) {
                final String shorTKEy = getShortName(key);
                if (super.get(shortKey) == null) {
                    super.put(shortKey, value);
                } else {
                    super.put(shortKey, (V) new Ambiguity(shortKey));
                }
            }
            return super.put(key, value);
        }

        public V get(Object key) {
            V value = super.get(key);
            if (value == null) {
                throw new IllegalArgumentException(name + " does not contain value for " + key);
            }
            if (value instanceof Ambiguity) {
                throw new IllegalArgumentException(((Ambiguity) value).getSubject() + " is ambiguous in " + name
                        + " (try using the full name including the namespace, or rename one of the entries)");
            }
            return value;
        }

        private String getShortName(String key) {
            final String[] keyparts = key.split("\\.");
            return keyparts[keyparts.length - 1];
        }

        protected static class Ambiguity {
            private String subject;

            public Ambiguity(String subject) {
                this.subject = subject;
            }

            public String getSubject() {
                return subject;
            }
        }
    }
}

package com.bzd.bootadmin.conf;

import com.bzd.core.mybatis.MapperRefresh;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.annotation.MapperScan;
import org.mybatis.spring.boot.autoconfigure.MybatisProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import javax.annotation.PostConstruct;

@Configuration
@MapperScan(value = {"com.bzd.bootadmin.modular.index.mapper"})
public class MybatisConfig {


    @Autowired
    SqlSessionFactory factory;

    @Autowired
    MybatisProperties properties;

    @PostConstruct
    public void postConstruct()  {
        Resource[] resources =  this.properties.resolveMapperLocations();
        new MapperRefresh(resources, factory.getConfiguration()).run();
    }



}

import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.core.io.Resource;

import javax.annotation.PostConstruct;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;


public class RefreshStarter {

    SqlSessionFactory factory;

    Resource[] mapperLocations;

    @PostConstruct
    public void postConstruct() throws IOException {
        Resource[] resources = mapperLocations;
        enableMybatisPlusRefresh(factory.getConfiguration());
        new MapperRefresh(resources, factory.getConfiguration()).run();
    }


    
    public void enableMybatisPlusRefresh(Configuration configuration){


        try {
            Method method = Class.forName("com.baomidou.mybatisplus.toolkit.GlobalConfigUtils")
                    .getMethod("getGlobalConfig", Configuration.class);
            Object globalConfiguration = method.invoke(null, configuration);
            method = Class.forName("com.baomidou.mybatisplus.entity.GlobalConfiguration")
                    .getMethod("setRefresh", boolean.class);
            method.invoke(globalConfiguration, true);
        } catch (ClassNotFoundException e) {

        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }


    public SqlSessionFactory getFactory() {
        return factory;
    }

    public void setFactory(SqlSessionFactory factory) {
        this.factory = factory;
    }

    public Resource[] getMapperLocations() {
        return mapperLocations;
    }

    public void setMapperLocations(Resource[] mapperLocations) {
        this.mapperLocations = mapperLocations;
    }
}

	<bean  class="com.foxtail.core.mybatis.RefreshStarter">
		<property name="mapperLocations">
			<array>
				<value>classpath:com/foxtail/mapping/*/*.xml</value>
				<value>classpath:com/foxtail/mapping/*.xml</value>
			</array>
		</property>
		<property name="factory" ref="sqlSessionFactory" />
	</bean>

#是否开启刷新线程  
enabled=true  
#延迟启动刷新程序的秒数  
delaySeconds=5 
#刷新扫描间隔的时长秒数  
sleepSeconds=3