Mybatis3.2不支持Ant通配符TypeAliasesPackage掃描的解決方案

業務場景

業務場景：首先項目進行分佈式拆分之後，按照模塊再分爲爲api層和service層，web層。
其中訂單業務的實體類放在com.muses.taoshop.item.entity，而用戶相關的實體類放在com.muses.taoshop.user.entity。所以就這樣，通過通配符方式去setTypeAliasesPackage ，com.muses.taoshop.*.entity

Ant通配符的3中風格：
(1) ?：匹配文件名中的一個字符 eg: com/test/entity? 匹配 com/test/entityaa
(2) * : 匹配文件名中的任意字符 eg: com/*/entity 匹配 com/test/entity
(3) ** ： 匹配文件名中的多重路徑 eg: com/**/entity 匹配 com/test/test1/entity

mybatis配置類寫在common工程，數據庫操作有些是可以共用的，不需要每個web工程都進行重複配置。
所以寫了個Mybatis配置類：

package com.muses.taoshop.common.core.database.config;
public class BaseConfig {

    /**
     * 設置主數據源名稱
     */
    public static final String DATA_SOURCE_NAME = "shop";

    /**
     * 加載配置文件信息
     */
    public static final String DATA_SOURCE_PROPERTIES = "spring.datasource.shop";

    /**
     * repository 所在包
     */
    public static final String REPOSITORY_PACKAGES = "com.muses.taoshop.**.repository";

    /**
     * mapper 所在包
     */
    public static final String MAPPER_PACKAGES = "com.muses.taoshop.**.mapper";

    /**
     * 實體類 所在包
     */
    public static final String ENTITY_PACKAGES = "com.muses.taoshop.*.entity";
...

}

貼一下配置類代碼，主要關注： factoryBean.setTypeAliasesPackage(ENTITY_PACKAGES);之前的寫法是這樣的。ENTITY_PACKAGES是個常量：public static final String ENTITY_PACKAGES = "com.muses.taoshop.*.entity";，ps：注意了，這裏用了通配符

package com.muses.taoshop.common.core.database.config;
//省略代碼
@MapperScan(
        basePackages = MAPPER_PACKAGES,
        annotationClass = MybatisRepository.class,
        sqlSessionFactoryRef = SQL_SESSION_FACTORY
)
@EnableTransactionManagement
@Configuration
public class MybatisConfig {
	//省略其它代碼，主要看sqlSessionFactory配置
    @Primary
    @Bean(name = SQL_SESSION_FACTORY)
    public SqlSessionFactory sqlSessionFactory(@Qualifier(DATA_SOURCE_NAME)DataSource dataSource)throws Exception{
        //SpringBoot默認使用DefaultVFS進行掃描，但是沒有掃描到jar裏的實體類
        VFS.addImplClass(SpringBootVFS.class);
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSource);
        //factoryBean.setConfigLocation(new ClassPathResource("mybatis-config.xml"));
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try{
            factoryBean.setMapperLocations(resolver.getResources("classpath*:/mybatis/*Mapper.xml"));
            //String typeAliasesPackage = packageScanner.getTypeAliasesPackages();
            //設置一下TypeAliasesPackage
            factoryBean.setTypeAliasesPackage(ENTITY_PACKAGES);
            SqlSessionFactory sqlSessionFactory = factoryBean.getObject();
            return sqlSessionFactory;
        }catch (Exception e){
            e.printStackTrace();
            throw new RuntimeException();
        }
    }

...

}

ps:原先做法：在sqlSessionFactory方法裏進行TypeAliasesPackage設置，(讓Mybatis能夠掃描到實體類，在xml文件裏就不需要寫全實體類的全包名了。)factoryBean.setTypeAliasesPackage(ENTITY_PACKAGES);

但是運行之後都會報錯，提示實體類不能掃描到，因爲我的service工程裏都是這樣寫的，ResultType進行用別名ItemCategory，例子：

 <!-- 獲取所有的商品品類信息-->
    <select id="listCategory" resultType="ItemCategory">
        SELECT 
        <include refid="BaseColumnList" />
        FROM item_category t
    </select>

源碼簡單分析

針對上面的業務場景，首先的分析一下，我們知道Mybatis的執行都會通過SQLSessionFactory去調用，調用前都是先用SqlSessionFactoryBean的setTypeAliasesPackage可以看一下SqlSessionFactoryBean的源碼：

/**
   * Packages to search for type aliases.
   *
   * @since 1.0.1
   *
   * @param typeAliasesPackage package to scan for domain objects
   *
   */
  public void setTypeAliasesPackage(String typeAliasesPackage) {
    this

我們看一下SqlSessionFactoryBean的初步Build方法：

/**
   * Build a {@code SqlSessionFactory} instance.
   *
   * The default implementation uses the standard MyBatis {@code XMLConfigBuilder} API to build a
   * {@code SqlSessionFactory} instance based on an Reader.
   * Since 1.3.0, it can be specified a {@link Configuration} instance directly(without config file).
   *
   * @return SqlSessionFactory
   * @throws IOException if loading the config file failed
   */
  protected SqlSessionFactory buildSqlSessionFactory() throws IOException {

    Configuration configuration;
//創建一個XMLConfigBuilder讀取配置文件的一些信息
    XMLConfigBuilder xmlConfigBuilder = null;
    if (this.configuration != null) {
      configuration = this.configuration;
      if (configuration.getVariables() == null) {
        configuration.setVariables(this.configurationProperties);
      } else if (this.configurationProperties != null) {
        configuration.getVariables().putAll(this.configurationProperties);//添加Properties屬性
      }
    } else if (this.configLocation != null) {
      xmlConfigBuilder = new XMLConfigBuilder(this.configLocation.getInputStream(), null, this.configurationProperties);
      configuration = xmlConfigBuilder.getConfiguration();
    } else {
      if (LOGGER.isDebugEnabled()) {
        LOGGER.debug("Property 'configuration' or 'configLocation' not specified, using default MyBatis Configuration");
      }
      configuration = new Configuration();
      if (this.configurationProperties != null) {
        configuration.setVariables(this.configurationProperties);
      }
    }

    if (this.objectFactory != null) {
      configuration.setObjectFactory(this.objectFactory);
    }

    if (this.objectWrapperFactory != null) {
      configuration.setObjectWrapperFactory(this.objectWrapperFactory);
    }

    if (this.vfs != null) {
      configuration.setVfsImpl(this.vfs);
    }
/*
重點看這裏，其它源碼先不看，這裏獲取到typeAliasesPackage字符串之後，調用tokenizeToStringArray進行字符串分隔返回一個數組，`String CONFIG_LOCATION_DELIMITERS = ",; \t\n";`
*/
    if (hasLength(this.typeAliasesPackage)) {
      String[] typeAliasPackageArray = tokenizeToStringArray(this.typeAliasesPackage,
          ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
      for (String packageToScan : typeAliasPackageArray) {//遍歷，註冊到configuration對象上
        configuration.getTypeAliasRegistry().registerAliases(packageToScan,
                typeAliasesSuperType == null ? Object.class : typeAliasesSuperType);
        if (LOGGER.isDebugEnabled()) {
          LOGGER.debug("Scanned package: '" + packageToScan + "' for aliases");
        }
      }
    }
    ...
    //省略其它代碼
}

然後可以看到註冊所有別名的方法 ，registerAliases是怎麼做的？

configuration.getTypeAliasRegistry().registerAliases(packageToScan,
                typeAliasesSuperType == null ? Object.class : typeAliasesSuperType);

要掃描註冊所有的別名之前先要掃描包下面的所有類：

public void registerAliases(String packageName, Class<?> superType) {
        ResolverUtil<Class<?>> resolverUtil = new ResolverUtil();
        resolverUtil.find(new IsA(superType), packageName);
       	//通過ResolverUtil獲取到的所有類都賦值給一個集合
        Set<Class<? extends Class<?>>> typeSet = resolverUtil.getClasses();
        /*遍歷集合，然後一個個註冊*/
        Iterator var5 = typeSet.iterator();
        while(var5.hasNext()) {
            Class<?> type = (Class)var5.next();
            if (!type.isAnonymousClass() && !type.isInterface() && !type.isMemberClass()) {
                this.registerAlias(type);
            }
        }

    }

ResolverUtil是怎麼通過packageName去查找的呢，可以再繼續跟一下

 public ResolverUtil<T> find(ResolverUtil.Test test, String packageName) {
 	//獲取包路徑
        String path = this.getPackagePath(packageName);

        try {
        //VFS類用單例模式實現，先獲取集合
            List<String> children = VFS.getInstance().list(path);
            Iterator var5 = children.iterator();
	   //遍歷,.class文件的選出來
            while(var5.hasNext()) {
                String child = (String)var5.next();
                if (child.endsWith(".class")) {
                    this.addIfMatching(test, child);
                }
            }
        } catch (IOException var7) {
            log.error("Could not read package: " + packageName, var7);
        }

        return this;
    }

獲取packPath只是獲取一下相對路徑

protected String getPackagePath(String packageName) {
        return packageName == null ? null : packageName.replace('.', '/');
    }

校驗方法addIfMatching：

 protected void addIfMatching(ResolverUtil.Test test, String fqn) {
        try {
            String externalName = fqn.substring(0, fqn.indexOf(46)).replace('/', '.');
            ClassLoader loader = this.getClassLoader();//類加載器
            if (log.isDebugEnabled()) {
                log.debug("Checking to see if class " + externalName + " matches criteria [" + test + "]");
            }

            Class<?> type = loader.loadClass(externalName);//通過類加載器加載類
            if (test.matches(type)) {//校驗是否符合
                this.matches.add(type);
            }
        } catch (Throwable var6) {
            log.warn("Could not examine class '" + fqn + "' due to a " + var6.getClass().getName() + " with message: " + var6.getMessage());
        }

    }

VFS類具體是怎麼setInstance的？繼續跟：

//這裏的關鍵點就是getResources，Thread.currentThread().getContextClassLoader().getResources()，其實總結一下Mybatis的類掃描還是要依賴與jdk提供的類加載器
 protected static List<URL> getResources(String path) throws IOException {
 //獲取到資源路徑以列表形式放在集合裏
        return Collections.list(Thread.currentThread().getContextClassLoader().getResources(path));
    }

    ...
    public List<String> list(String path) throws IOException {
        List<String> names = new ArrayList();
        Iterator var3 = getResources(path).iterator();
	//遍歷封裝成列表
        while(var3.hasNext()) {
            URL url = (URL)var3.next();
            names.addAll(this.list(url, path));
        }

        return names;
    }

ok，本博客只是稍微跟一下源碼，並沒有對Mybatis的源碼進行比較系統更高層次的分析。
跟了一下源碼知道，稍微總結一下Mybatis對別名的註冊是先將從sqlSessionFactoryBean類set的別名報名進行tokenizeToStringArray拆分成數組，然後將包名數組丟給ResolverUtil類和VFS等類進行一系列類加載遍歷，之後將 resolverUtil.getClasses()獲取的類都賦值給Set<Class<? extends Class<?>>> typeSet 一個集合。其中也是依賴與類加載器。

支持Ant通配符方式setTypeAliasesPackage解決方案

從這個源碼比較簡單的分析過程，我們並沒有找到支持所謂通配符的方法，通過類加載的話也是要傳個相對路徑去遍歷，不過我上面描述的業務場景是要兼容通配符的情況的，一般不會去改包名，假如這個項目有一定規模的話。

下面給出我的解決方案：

package com.muses.taoshop.common.core.database.annotation;

import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.util.ClassUtils;

import static com.muses.taoshop.common.core.database.config.BaseConfig.ENTITY_PACKAGES;

public class AnnotationConstants {

    public static final String DEFAULT_RESOURCE_PATTERN = "**/*.class";

    public final static String PACKAGE_PATTERN =
            ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
            + ClassUtils.convertClassNameToResourcePath(ENTITY_PACKAGES)
            + DEFAULT_RESOURCE_PATTERN;

}

寫一個掃描類，代碼參考Hibernate的AnnotationSessionFactoryBean源碼

package com.muses.taoshop.common.core.database.annotation;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;

import java.io.IOException;
import java.util.*;

import org.springframework.core.io.Resource;
import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;
import org.thymeleaf.util.StringUtils;

import static com.muses.taoshop.common.core.database.annotation.AnnotationConstants.PACKAGE_PATTERN;

/**
 * <pre>
 *  TypeAlicsesPackage的掃描類
 * </pre>
 *
 * @author nicky
 * @version 1.00.00
 * <pre>
 * 修改記錄
 *    修改後版本:     修改人：  修改日期: 2018.12.01 18:23    修改內容:
 * </pre>
 */
@Component
public class TypeAliasesPackageScanner {

    protected final static Logger LOGGER = LoggerFactory.getLogger(TypeAliasesPackageScanner.class);
    private static ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
   /* private TypeFilter[] entityTypeFilters = new TypeFilter[]{new AnnotationTypeFilter(Entity.class, false),
            new AnnotationTypeFilter(Embeddable.class, false),
            new AnnotationTypeFilter(MappedSuperclass.class, false),
            new AnnotationTypeFilter(org.hibernate.annotations.Entity.class, false)};*/


    public static String getTypeAliasesPackages() {
        Set<String> packageNames = new TreeSet<String>();
        //TreeSet packageNames = new TreeSet();
        String typeAliasesPackage ="";
        try {
            //加載所有的資源
            Resource[] resources = resourcePatternResolver.getResources(PACKAGE_PATTERN);
            MetadataReaderFactory readerFactory = new CachingMetadataReaderFactory(resourcePatternResolver);
            //遍歷資源
            for (Resource resource : resources) {
                if (resource.isReadable()) {
                    MetadataReader reader = readerFactory.getMetadataReader(resource);
                    String className = reader.getClassMetadata().getClassName();
                    //eg:com.muses.taoshop.item.entity.ItemBrand
                    LOGGER.info("className : {} "+className);
                    try{
                        //eg:com.muses.taoshop.item.entity
                        LOGGER.info("packageName : {} "+Class.forName(className).getPackage().getName());
                        packageNames.add(Class.forName(className).getPackage().getName());
                    }catch (ClassNotFoundException e){
                        LOGGER.error("classNotFoundException : {} "+e);
                    }
                }
            }
        } catch (IOException e) {
            LOGGER.error("ioException =>: {} " + e);
        }
        //集合不爲空的情況，拼裝一下數據
        if (!CollectionUtils.isEmpty(packageNames)) {
            typeAliasesPackage = StringUtils.join(packageNames.toArray() , ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
        }else{
            LOGGER.info("set empty,size:{} "+packageNames.size());
        }
        return typeAliasesPackage;
    }

    
}

然後剛纔的Mybatis配置類改一下，主要改 String typeAliasesPackage = packageScanner.getTypeAliasesPackages();通過掃描類去獲取一下，重點代碼在TypeAliasesPackageScanner 掃描類

package com.muses.taoshop.common.core.database.config;
//省略代碼
@MapperScan(
        basePackages = MAPPER_PACKAGES,
        annotationClass = MybatisRepository.class,
        sqlSessionFactoryRef = SQL_SESSION_FACTORY
)
@EnableTransactionManagement
@Configuration
public class MybatisConfig {
	//省略其它代碼，主要看sqlSessionFactory配置
    @Primary
    @Bean(name = SQL_SESSION_FACTORY)
    public SqlSessionFactory sqlSessionFactory(@Qualifier(DATA_SOURCE_NAME)DataSource dataSource)throws Exception{
        //SpringBoot默認使用DefaultVFS進行掃描，但是沒有掃描到jar裏的實體類
        VFS.addImplClass(SpringBootVFS.class);
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSource);
        //factoryBean.setConfigLocation(new ClassPathResource("mybatis-config.xml"));
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try{
            factoryBean.setMapperLocations(resolver.getResources("classpath*:/mybatis/*Mapper.xml"));
            String typeAliasesPackage = packageScanner.getTypeAliasesPackages();
            //設置一下TypeAliasesPackage
            factoryBean.setTypeAliasesPackage(typeAliasesPackage);
            SqlSessionFactory sqlSessionFactory = factoryBean.getObject();
            return sqlSessionFactory;
        }catch (Exception e){
            e.printStackTrace();
            throw new RuntimeException();
        }
    }