关于MyBatis中Mapper XML热加载优化
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前几天在琢磨mybatis xml热加载的问题，原理还是通过定时扫描xml文件去跟新，但放到项目上就各种问题，由于用了mybatisplus死活不生效。本着"即插即用"的原则，狠心把其中的代码优化了一遍，能够兼容mybatisplus，还加入了一些日志，直接上代码
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;
}
}
}
}
这里提供两种配置方式一种是springboot，一种就是普通的spring项目
1.springboot 方式 就是
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();
}
}
2：普通spring项目
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;
}
}
在xml中配置
<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>
最后在resources中加入mybatis-refresh.properties
#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
到这里就大功告成了，最后加到代码里面有没有生效呢，改完sql之后总会想到底是更新了还是没更新，又看不到，这是程序员最头疼的。因为加了日志都不用担心啦
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