hibernate根据条件动态组装sql/hql语句(仿ibatis动态查询语句功能)

1.功能需求背景
  项目中使用hibernate作为数据持久层框架,主要考虑hibernate在进行一些简单的crud操作时非常便利,不需要和ibatis似的为每个sql操作都写一堆文件,但是同时也带来了一些局限性,如类似ibatis强大的动态查询功能用不了了,但是这个功能在项目中的应用场景又很大,hibernate自身也支持将sql/hql语句写在.hbm.xml映射文件中<sql-query>和<query>元素,但是这个功能只能对那些查询限制条件固定的sql有用,对于需要动态拼接的sql语句,hibernate就显得力不从心了,如何给hibernate插上ibatis动态查询的翅膀,既保留crud的简洁性,又能收获ibatis的特性呢?接下来的文章将会重点介绍
2.设计思路
  先看一下ibatis的动态查询时怎么做的
     <select id="getUserList" resultMap="user">
         select * from user
            <isGreaterThan prepend="and" property="id" compareValue="0">
                   where user_id = #userId#
            </isGreaterThan>
             order by createTime desc
    </select>
  ibatis在程序实现内部回去解析sql语句中的标签,然后去解析计算,我们在ibatis在实现的时候也参考了这个解决思路,但是否是需要把ibatis里的解析sql的语法都抄到我们的dao框架中呢-显然这样太复杂了,而且ibatis自己的sql元素是和那些resultMap等是绑定在一起用的,而在hibernate是没用这些东西的,要改造这些东西是一项非常浩大的工程,因此这个方案被放弃了

  我们在实现的时候采取了一种非常简洁又功能强大的方式-模板技术!对,就是利用freemarker把sql/hql中的动态拼接条件判断语法都交给freemarker语法去处理,这样既能复用freemarker框架,又保持了我们框架设计的简洁性-不需要自己写过多的处理逻辑,以下是我们需要进行动态处理的sql/hql语句的样例

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE dynamic-hibernate-statement PUBLIC "-//Haier/HOP Hibernate Dynamic Statement DTD 1.0//EN"
"http://www.haier.com/dtd/dynamic-hibernate-statement-1.0.dtd">
<dynamic-hibernate-statement>
	<!-- 查询某个资源下的直接子节点 -->
	<hql-query name="resource.getChildren">
	<![CDATA[
		from Resource where parent.id=${parentId} and parent.id != id
	]]> 
	</hql-query>
	<!-- 查询系统中所有的root资源 -->
	<hql-query name="resource.getRoots">
	<![CDATA[
		from Resource where parent.id = id order by orderIndex
	]]> 
	</hql-query>
	<!-- 获取某个用户可访问的某个资源下的所有子资源 -->
	<sql-query name="resource.getDescendants">
	<![CDATA[
		select distinct t.id,
		                t.name,
		                t.description,
		                t.url,
		                t.type,
		                t.status,
		                t.code,
		                t.configuration,
		                t.module_name,
		                t.gmt_create,
		                t.gmt_modified,
		                t.create_by,
		                t.last_modified_by,
		                t.order_index,
		                t.parent_id
		  from resource_info t
		 inner join role_resource rr
		    on t.id = rr.resource_id
		 inner join user_role ur
		    on rr.role_id = ur.role_id
		 where ur.user_id = ${userId}
		 <#if type == '1'>
		 	and t.type=1
		 	<#else>
		 	and t.type=0
		 </#if>
		   and t.type =  ${type}
		   and t.status =  ${status}
		 start with t.code = '${code}'
		connect by nocycle prior t.id = t.parent_id
	]]> 
	</sql-query>
</dynamic-hibernate-statement>
这个文件看起来非常类似ibatis的语句了,只是没用ibatis的哪些标签-改成了freemarker语法,没错,我们就是复用freemarker来帮我们解决这些烦杂的判断操作的

这样我们的动态sql程序就可以总结成以下流程

a.系统加载阶段

  这个阶段程序负责将指定路径下的动态sql文件加载到内存中,一次性缓存起来,没错,这些东西只需要加载一次,以后直接读取就行了,没必要每次去查找,缓存也非常简单,一个Map<String,String>就搞定,key是sql-query或hql-query元素的name属性,value就是与其对应的sql/hql语句

b.程序调用查询阶段

   调用程序通过sql/hql语句的name属性和传入查询参数来得到最终解析出来的语句

我们期望的方法可能是这样的:

public <X> List<X> findByNamedQuery(final String queryName, final Map<String, ?> parameters) 
通过queryName从缓存中查找出其对应的sql/hql语句(最原始的,里面带有freemarker语法)

然后通过freemarker模板和传递进去的parameters参数对模板进行解析,得到最终的语句(纯sql/hql)

最后将解析后的sql/hql传递给底层api,返回查询结果

3.实现

  上面介绍了大致的思路,这里介绍具体的代码实现

  3.1DTD定义

      我们是把动态的sql/hql语句放在单独的xml配置文件里的,为了规范xml文档,我们给文档定义了dtd文件,这里我们只定义了两个元素<sql-query>和<hql-query>分别表示sql查询语句和hql查询语句,这两个元素目前自有一个name属性用来唯一标示该语句,如下

<!-- HOP Hibernate Dynamic Statement Mapping DTD.

<!DOCTYPE dynamic-hibernate-statement PUBLIC 
    "-//Haier/HOP Hibernate Dynamic Statement DTD 1.0//EN"
    "http://www.haier.com/dtd/dynamic-hibernate-statement-1.0.dtd">

这个文件时用来定义动态参数语句,类似itabis

-->

<!--
	The document root.
 -->

<!ELEMENT dynamic-hibernate-statement (
	(hql-query|sql-query)*
)>
							<!-- default: none -->

<!-- The query element declares a named Hibernate query string -->

<!ELEMENT hql-query (#PCDATA)>
	<!ATTLIST hql-query name CDATA #REQUIRED>

<!-- The sql-query element declares a named SQL query string -->

<!ELEMENT sql-query (#PCDATA)>
	<!ATTLIST sql-query name CDATA #REQUIRED>

然后将其保存为dynamic-hibernate-statement-1.0.dtd,放在classpath下

编写DTD校验器

/**
 * hibernate动态sql dtd解析器
 * @author WangXuzheng
 *
 */
public class DynamicStatementDTDEntityResolver implements EntityResolver, Serializable{
	private static final long serialVersionUID = 8123799007554762965L;
	private static final Logger LOGGER = LoggerFactory.getLogger( DynamicStatementDTDEntityResolver.class );
	private static final String HOP_DYNAMIC_STATEMENT = "http://www.haier.com/dtd/";

	public InputSource resolveEntity(String publicId, String systemId) {
		InputSource source = null; // returning null triggers default behavior
		if ( systemId != null ) {
			LOGGER.debug( "trying to resolve system-id [" + systemId + "]" );
			if ( systemId.startsWith( HOP_DYNAMIC_STATEMENT ) ) {
				LOGGER.debug( "recognized hop dyanmic statement namespace; attempting to resolve on classpath under com/haier/openplatform/dao/hibernate/" );
				source = resolveOnClassPath( publicId, systemId, HOP_DYNAMIC_STATEMENT );
			}
		}
		return source;
	}

	private InputSource resolveOnClassPath(String publicId, String systemId, String namespace) {
		InputSource source = null;
		String path = "com/haier/openplatform/dao/hibernate/" + systemId.substring( namespace.length() );
		InputStream dtdStream = resolveInHibernateNamespace( path );
		if ( dtdStream == null ) {
			LOGGER.debug( "unable to locate [" + systemId + "] on classpath" );
			if ( systemId.substring( namespace.length() ).indexOf( "2.0" ) > -1 ) {
				LOGGER.error( "Don't use old DTDs, read the Hibernate 3.x Migration Guide!" );
			}
		}
		else {
			LOGGER.debug( "located [" + systemId + "] in classpath" );
			source = new InputSource( dtdStream );
			source.setPublicId( publicId );
			source.setSystemId( systemId );
		}
		return source;
	}

	protected InputStream resolveInHibernateNamespace(String path) {
		return this.getClass().getClassLoader().getResourceAsStream( path );
	}

	protected InputStream resolveInLocalNamespace(String path) {
		try {
			return ConfigHelper.getUserResourceAsStream( path );
		}
		catch ( Throwable t ) {
			return null;
		}
	}
}

3.2编写sql文件

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE dynamic-hibernate-statement PUBLIC "-//Haier/HOP Hibernate Dynamic Statement DTD 1.0//EN"
"http://www.haier.com/dtd/dynamic-hibernate-statement-1.0.dtd">
<dynamic-hibernate-statement>
	<!-- 查询某个资源下的直接子节点 -->
	<hql-query name="resource.getChildren">
	<![CDATA[
		from Resource where parent.id=${parentId} and parent.id != id
	]]> 
	</hql-query>
	<!-- 查询系统中所有的root资源 -->
	<hql-query name="resource.getRoots">
	<![CDATA[
		from Resource where parent.id = id order by orderIndex
	]]> 
	</hql-query>
	<!-- 获取某个用户可访问的某个资源下的所有子资源 -->
	<sql-query name="resource.getDescendants">
	<![CDATA[
		select distinct t.id,
		                t.name,
		                t.description,
		                t.url,
		                t.type,
		                t.status,
		                t.code,
		                t.configuration,
		                t.module_name,
		                t.gmt_create,
		                t.gmt_modified,
		                t.create_by,
		                t.last_modified_by,
		                t.order_index,
		                t.parent_id
		  from resource_info t
		 inner join role_resource rr
		    on t.id = rr.resource_id
		 inner join user_role ur
		    on rr.role_id = ur.role_id
		 where ur.user_id = ${userId}
		 <#if type == '1'>
		 	and t.type=1
		 	<#else>
		 	and t.type=0
		 </#if>
		   and t.type =  ${type}
		   and t.status =  ${status}
		 start with t.code = '${code}'
		connect by nocycle prior t.id = t.parent_id
	]]> 
	</sql-query>
</dynamic-hibernate-statement>
3.3加载动态sql文件

这里我们将加载sql/hql语句的程序独立到一个单独的类中,以便独立扩展

这里一共3个方法,分表标示获取系统中sql/hql语句的map(key:语句名称,value:具体的)

/**
 * 动态sql/hql语句组装器
 * @author WangXuzheng
 *
 */
public interface DynamicHibernateStatementBuilder {
	/**
	 * hql语句map
	 * @return
	 */
	public Map<String,String> getNamedHQLQueries();
	/**
	 * sql语句map
	 * @return
	 */
	public Map<String,String> getNamedSQLQueries();
	/**
	 * 初始化
	 * @throws IOException 
	 */
	public void init() throws IOException;
}
默认的加载器-将指定配置文件中的sql/hql语句加载到内存中
/**
 * @author WangXuzheng
 *
 */
public class DefaultDynamicHibernateStatementBuilder implements DynamicHibernateStatementBuilder, ResourceLoaderAware {
	private static final Logger LOGGER = LoggerFactory.getLogger(DefaultDynamicHibernateStatementBuilder.class);
	private Map<String, String> namedHQLQueries;
	private Map<String, String> namedSQLQueries;
	private String[] fileNames = new String[0];
	private ResourceLoader resourceLoader;
	private EntityResolver entityResolver = new DynamicStatementDTDEntityResolver();
	/**
	 * 查询语句名称缓存,不允许重复
	 */
	private Set<String> nameCache = new HashSet<String>();

	public void setFileNames(String[] fileNames) {
		this.fileNames = fileNames;
	}

	@Override
	public Map<String, String> getNamedHQLQueries() {
		return namedHQLQueries;
	}

	@Override
	public Map<String, String> getNamedSQLQueries() {
		return namedSQLQueries;
	}

	@Override
	public void init() throws IOException {
		namedHQLQueries = new HashMap<String, String>();
		namedSQLQueries = new HashMap<String, String>();
		boolean flag = this.resourceLoader instanceof ResourcePatternResolver;
		for (String file : fileNames) {
			if (flag) {
				Resource[] resources = ((ResourcePatternResolver) this.resourceLoader).getResources(file);
				buildMap(resources);
			} else {
				Resource resource = resourceLoader.getResource(file);
				buildMap(resource);
			}
		}
		//clear name cache
		nameCache.clear();
	}

	@Override
	public void setResourceLoader(ResourceLoader resourceLoader) {
		this.resourceLoader = resourceLoader;
	}

	private void buildMap(Resource[] resources) throws IOException {
		if (resources == null) {
			return;
		}
		for (Resource resource : resources) {
			buildMap(resource);
		}
	}

	@SuppressWarnings({ "rawtypes" })
	private void buildMap(Resource resource) {
		InputSource inputSource = null;
		try {
			inputSource = new InputSource(resource.getInputStream());
			XmlDocument metadataXml = MappingReader.INSTANCE.readMappingDocument(entityResolver, inputSource,
					new OriginImpl("file", resource.getFilename()));
			if (isDynamicStatementXml(metadataXml)) {
				final Document doc = metadataXml.getDocumentTree();
				final Element dynamicHibernateStatement = doc.getRootElement();
				Iterator rootChildren = dynamicHibernateStatement.elementIterator();
				while (rootChildren.hasNext()) {
					final Element element = (Element) rootChildren.next();
					final String elementName = element.getName();
					if ("sql-query".equals(elementName)) {
						putStatementToCacheMap(resource, element, namedSQLQueries);
					} else if ("hql-query".equals(elementName)) {
						putStatementToCacheMap(resource, element, namedHQLQueries);
					}
				}
			}
		} catch (Exception e) {
			LOGGER.error(e.toString());
			throw new SysException(e);
		} finally {
			if (inputSource != null && inputSource.getByteStream() != null) {
				try {
					inputSource.getByteStream().close();
				} catch (IOException e) {
					LOGGER.error(e.toString());
					throw new SysException(e);
				}
			}
		}

	}

	private void putStatementToCacheMap(Resource resource, final Element element, Map<String, String> statementMap)
			throws IOException {
		String sqlQueryName = element.attribute("name").getText();
		Validate.notEmpty(sqlQueryName);
		if (nameCache.contains(sqlQueryName)) {
			throw new SysException("重复的sql-query/hql-query语句定义在文件:" + resource.getURI() + "中,必须保证name的唯一.");
		}
		nameCache.add(sqlQueryName);
		String queryText = element.getText();
		statementMap.put(sqlQueryName, queryText);
	}

	private static boolean isDynamicStatementXml(XmlDocument xmlDocument) {
		return "dynamic-hibernate-statement".equals(xmlDocument.getDocumentTree().getRootElement().getName());
	}
}
配置一下
	<bean id="dynamicStatementBuilder" class="com.haier.openplatform.dao.hibernate.support.DefaultDynamicHibernateStatementBuilder">
		<property name="fileNames">
			<list>
				<value>classpath*:/**/*-dynamic.xml</value><!--这里我们指定要加载某个文件夹下所有以-dynamic.xml结尾的文件 -->
			</list>
		</property>
	</bean>
    <bean id="baseHibernateDAO" class="com.haier.openplatform.dao.hibernate.BaseDAOHibernateImpl" abstract="true">
        <property name="sessionFactory">
            <ref bean="sessionFactory"/>
        </property>
        <property name="dynamicStatementBuilder" ref="dynamicStatementBuilder"/>
    </bean>
dao层代码
/**
 * Hibernate实现的DAO层
 * @param <T> DAO操作的对象类型
 * @param <ID> 主键类型
 * @author WangXuzheng
 *
 */
public class SimpleHibernateDAO<T,ID extends Serializable> implements BaseDAO<T, ID>,InitializingBean{
	private static final Logger LOGER = LoggerFactory.getLogger(SimpleHibernateDAO.class);
	protected SessionFactory sessionFactory;
	protected Class<T> entityClass;
	/**
	 * 模板缓存
	 */
	protected Map<String, StatementTemplate> templateCache;
	protected DynamicHibernateStatementBuilder dynamicStatementBuilder;
	/**
	 * 通过子类的泛型定义取得对象类型Class.
	 * eg.
	 * public class UserDao extends SimpleHibernateDao<User, Long>
	 */
	public SimpleHibernateDAO() {
		this.entityClass = Reflections.getSuperClassGenricType(getClass());
	}

	/**
	 * 取得sessionFactory.
	 */
	public SessionFactory getSessionFactory() {
		return sessionFactory;
	}

	/**
	 * 采用@Autowired按类型注入SessionFactory, 当有多个SesionFactory的时候在子类重载本函数.
	 */
	public void setSessionFactory(final SessionFactory sessionFactory) {
		this.sessionFactory = sessionFactory;
	}

	public void setDynamicStatementBuilder(DynamicHibernateStatementBuilder dynamicStatementBuilder) {
		this.dynamicStatementBuilder = dynamicStatementBuilder;
	}

	/**
	 * 取得当前Session.
	 */
	public Session getSession() {
		return sessionFactory.getCurrentSession();
	}

	/**
	 * 保存新增或修改的对象.
	 */
	@Override
	public void save(final T entity) {
		Validate.notNull(entity, "entity不能为空");
		getSession().save(entity);
		LOGER.debug("save entity: {}", entity);
	}

	/**
	 * 删除对象.
	 * 
	 * @param entity 对象必须是session中的对象或含id属性的transient对象.
	 */
	@Override
	public void delete(final T entity) {
		if(entity == null){
			return;
		}
		getSession().delete(entity);
		LOGER.debug("delete entity: {}", entity);
	}

	/**
	 * 按id删除对象.
	 */
	@Override
	public void delete(final ID id) {
		Validate.notNull(id, "id不能为空");
		delete(get(id));
		LOGER.debug("delete entity {},id is {}", entityClass.getSimpleName(), id);
	}

	/**
	 * 按id获取对象.
	 */
	@SuppressWarnings("unchecked")
	@Override
	public T get(final ID id) {
		Validate.notNull(id, "id不能为空");
		return (T) getSession().get(entityClass, id);
	}

	/**
	 * 按id列表获取对象列表.
	 */
	public List<T> get(final Collection<ID> ids) {
		return find(Restrictions.in(getIdName(), ids));
	}

	/**
	 *	获取全部对象.
	 */
	@Override
	public List<T> getAll() {
		return find();
	}

	/**
	 *	获取全部对象, 支持按属性行序.
	 */
	@SuppressWarnings("unchecked")
	public List<T> getAll(String orderByProperty, boolean isAsc) {
		Criteria c = createCriteria();
		if (isAsc) {
			c.addOrder(Order.asc(orderByProperty));
		} else {
			c.addOrder(Order.desc(orderByProperty));
		}
		return c.list();
	}

	/**
	 * 按属性查找对象列表, 匹配方式为相等.
	 */
	public List<T> findBy(final String propertyName, final Object value) {
		Criterion criterion = Restrictions.eq(propertyName, value);
		return find(criterion);
	}

	/**
	 * 按属性查找唯一对象, 匹配方式为相等.
	 */
	@SuppressWarnings("unchecked")
	@Override
	public T findUniqueBy(final String propertyName, final Object value) {
		Criterion criterion = Restrictions.eq(propertyName, value);
		return ((T) createCriteria(criterion).uniqueResult());
	}

	/**
	 * 按HQL查询对象列表.
	 * 
	 * @param values 数量可变的参数,按顺序绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> List<X> findByHQL(final String hql, final Object... values) {
		return createHQLQuery(hql, values).list();
	}
	
	/**
	 * 按HQL查询对象列表,并将对象封装成指定的对象
	 * 
	 * @param values 数量可变的参数,按顺序绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> List<X> findByHQLRowMapper(RowMapper<X> rowMapper,final String hql, final Object... values) {
		Validate.notNull(rowMapper, "rowMapper不能为空!");
		List<Object[]> result = createHQLQuery(hql, values).list();
		return buildListResultFromRowMapper(rowMapper, result);
	}

	protected <X> List<X> buildListResultFromRowMapper(RowMapper<X> rowMapper, List<Object[]> result) {
		List<X> rs = new ArrayList<X>(result.size());
		for(Object[] obj : result){
			rs.add(rowMapper.fromColumn(obj));
		}
		return rs;
	}
	
	
	/**
	 * 按SQL查询对象列表.
	 * 
	 * @param values 数量可变的参数,按顺序绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> List<X> findBySQLRowMapper(RowMapper<X> rowMapper,final String sql, final Object... values) {
		Validate.notNull(rowMapper, "rowMapper不能为空!");
		List<Object[]> result = createSQLQuery(sql, values).list();
		return buildListResultFromRowMapper(rowMapper, result);
	}
	
	/**
	 * 按SQL查询对象列表,并将结果集转换成指定的对象列表
	 * 
	 * @param values 数量可变的参数,按顺序绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> List<X> findBySQL(final String sql, final Object... values) {
		return createSQLQuery(sql, values).list();
	}

	/**
	 * 按HQL查询对象列表.
	 * 
	 * @param values 命名参数,按名称绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> List<X> findByHQL(final String hql, final Map<String, ?> values) {
		return createHQLQuery(hql, values).list();
	}
	
	/**
	 * 按HQL查询对象列表,并将结果集封装成对象列表
	 * 
	 * @param values 命名参数,按名称绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> List<X> findByHQLRowMapper(RowMapper<X> rowMapper,final String hql, final Map<String, ?> values) {
		Validate.notNull(rowMapper, "rowMapper不能为空!");
		List<Object[]> result = createHQLQuery(hql, values).list();
		return buildListResultFromRowMapper(rowMapper, result);
	}
	
	/**
	 * 按SQL查询对象列表.
	 * @param sql SQL查询语句
	 * @param values 命名参数,按名称绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> List<X> findBySQL(final String sql, final Map<String, ?> values) {
		return createSQLQuery(sql, values).list();
	}
	
	/**
	 * 查询在xxx.hbm.xml中配置的查询语句
	 * @param queryName 查询的名称
	 * @param parameters 参数
	 * @return
	 */
	public <X> List<X> findByNamedQuery(final String queryName, final Map<String, ?> parameters) {
		StatementTemplate statementTemplate = templateCache.get(queryName);
		String statement = processTemplate(statementTemplate,parameters);
		if(statementTemplate.getType() == StatementTemplate.TYPE.HQL){
			return this.findByHQL(statement);
		}else{
			return this.findBySQL(statement);
		}
	}
	
	/**
	 * 查询在xxx.hbm.xml中配置的查询语句
	 * @param rowMapper
	 * @param queryName 查询的名称
	 * @param parameters 参数
	 * @return
	 */
	public <X> List<X> findByNamedQuery(RowMapper<X> rowMapper,final String queryName, final Map<String, ?> parameters) {
		StatementTemplate statementTemplate = templateCache.get(queryName);
		String statement = processTemplate(statementTemplate,parameters);
		if(statementTemplate.getType() == StatementTemplate.TYPE.HQL){
			return this.findByHQLRowMapper(rowMapper,statement);
		}else{
			return this.findBySQLRowMapper(rowMapper,statement);
		}
	}
	
	/**
	 * 按SQL查询对象列表,并将结果集封装成对象列表
	 * @param sql SQL查询语句
	 * @param values 命名参数,按名称绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> List<X> findBySQLRowMapper(RowMapper<X> rowMapper,final String sql, final Map<String, ?> values) {
		Validate.notNull(rowMapper, "rowMapper不能为空!");
		List<Object[]> result = createSQLQuery(sql, values).list();
		return buildListResultFromRowMapper(rowMapper, result);
	}

	/**
	 * 按HQL查询唯一对象.
	 * 
	 * @param values 数量可变的参数,按顺序绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> X findUniqueByHQL(final String hql, final Object... values) {
		return (X) createHQLQuery(hql, values).uniqueResult();
	}
	
	/**
	 * 按SQL查询唯一对象.
	 * 
	 * @param values 数量可变的参数,按顺序绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> X findUniqueBySQL(final String sql, final Object... values) {
		return (X) createSQLQuery(sql, values).uniqueResult();
	}

	/**
	 * 按HQL查询唯一对象.
	 * 
	 * @param values 命名参数,按名称绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> X findUniqueByHQL(final String hql, final Map<String, ?> values) {
		return (X) createHQLQuery(hql, values).uniqueResult();
	}
	
	/**
	 * 按HQL查询唯一对象.
	 * @param sql sql语句
	 * @param values 命名参数,按名称绑定.
	 */
	@SuppressWarnings("unchecked")
	public <X> X findUniqueBySQL(final String sql, final Map<String, ?> values) {
		return (X) createSQLQuery(sql, values).uniqueResult();
	}

	/**
	 * 执行HQL进行批量修改/删除操作.
	 * 
	 * @param values 数量可变的参数,按顺序绑定.
	 * @return 更新记录数.
	 */
	public int batchExecuteHQL(final String hql, final Object... values) {
		return createHQLQuery(hql, values).executeUpdate();
	}
	
	/**
	 * 执行SQL进行批量修改/删除操作.
	 * 
	 * @param sql sql语句
	 * @param values 数量可变的参数,按顺序绑定.
	 * @return 更新记录数.
	 */
	public int batchExecuteSQL(final String sql, final Object... values) {
		return createSQLQuery(sql, values).executeUpdate();
	}

	/**
	 * 执行HQL进行批量修改/删除操作.
	 * 
	 * @param values 命名参数,按名称绑定.
	 * @return 更新记录数.
	 */
	public int batchExecuteHQL(final String hql, final Map<String, ?> values) {
		return createHQLQuery(hql, values).executeUpdate();
	}
	
	/**
	 * 执行SQL进行批量修改/删除操作.
	 * 
	 * @param values 命名参数,按名称绑定.
	 * @return 更新记录数.
	 */
	public int batchExecuteSQL(final String sql, final Map<String, ?> values) {
		return createSQLQuery(sql, values).executeUpdate();
	}

	/**
	 * 根据查询HQL与参数列表创建Query对象.
	 * 与find()函数可进行更加灵活的操作.
	 * 
	 * @param values 数量可变的参数,按顺序绑定.
	 */
	public Query createHQLQuery(final String queryString, final Object... values) {
		Query query = getSession().createQuery(queryString);
		if (values != null) {
			for (int i = 0; i < values.length; i++) {
				query.setParameter(i, values[i]);
			}
		}
		return query;
	}
	
	/**
	 * 根据查询SQL与参数列表创建Query对象.
	 * 与find()函数可进行更加灵活的操作.
	 * @param sqlQueryString sql语句
	 * 
	 * @param values 数量可变的参数,按顺序绑定.
	 */
	public Query createSQLQuery(final String sqlQueryString, final Object... values) {
		Query query = getSession().createSQLQuery(sqlQueryString);
		if (values != null) {
			for (int i = 0; i < values.length; i++) {
				query.setParameter(i, values[i]);
			}
		}
		return query;
	}

	/**
	 * 根据查询HQL与参数列表创建Query对象.
	 * 与find()函数可进行更加灵活的操作.
	 * 
	 * @param values 命名参数,按名称绑定.
	 */
	public Query createHQLQuery(final String queryString, final Map<String, ?> values) {
		Query query = getSession().createQuery(queryString);
		if (values != null) {
			query.setProperties(values);
		}
		return query;
	}
	
	/**
	 * 根据查询SQL与参数列表创建Query对象.
	 * 与find()函数可进行更加灵活的操作.
	 * @param queryString SQL语句
	 * @param values 命名参数,按名称绑定.
	 */
	public Query createSQLQuery(final String queryString, final Map<String, ?> values) {
		Query query = getSession().createSQLQuery(queryString);
		if (values != null) {
			query.setProperties(values);
		}
		return query;
	}

	/**
	 * 按Criteria查询对象列表.
	 * 
	 * @param criterions 数量可变的Criterion.
	 */
	@SuppressWarnings("unchecked")
	public List<T> find(final Criterion... criterions) {
		return createCriteria(criterions).list();
	}

	/**
	 * 按Criteria查询唯一对象.
	 * 
	 * @param criterions 数量可变的Criterion.
	 */
	@SuppressWarnings("unchecked")
	public T findUnique(final Criterion... criterions) {
		return (T) createCriteria(criterions).uniqueResult();
	}

	/**
	 * 根据Criterion条件创建Criteria.
	 * 与find()函数可进行更加灵活的操作.
	 * 
	 * @param criterions 数量可变的Criterion.
	 */
	public Criteria createCriteria(final Criterion... criterions) {
		Criteria criteria = getSession().createCriteria(entityClass);
		for (Criterion c : criterions) {
			criteria.add(c);
		}
		return criteria;
	}

	/**
	 * 初始化对象.
	 * 使用load()方法得到的仅是对象Proxy, 在传到View层前需要进行初始化.
	 * 如果传入entity, 则只初始化entity的直接属性,但不会初始化延迟加载的关联集合和属性.
	 * 如需初始化关联属性,需执行:
	 * Hibernate.initialize(user.getRoles()),初始化User的直接属性和关联集合.
	 * Hibernate.initialize(user.getDescription()),初始化User的直接属性和延迟加载的Description属性.
	 */
	public void initProxyObject(Object proxy) {
		Hibernate.initialize(proxy);
	}

	/**
	 * Flush当前Session.
	 */
	public void flush() {
		getSession().flush();
	}

	/**
	 * 为Query添加distinct transformer.
	 * 预加载关联对象的HQL会引起主对象重复, 需要进行distinct处理.
	 */
	public Query distinct(Query query) {
		query.setResultTransformer(CriteriaSpecification.DISTINCT_ROOT_ENTITY);
		return query;
	}

	/**
	 * 为Criteria添加distinct transformer.
	 * 预加载关联对象的HQL会引起主对象重复, 需要进行distinct处理.
	 */
	public Criteria distinct(Criteria criteria) {
		criteria.setResultTransformer(CriteriaSpecification.DISTINCT_ROOT_ENTITY);
		return criteria;
	}

	/**
	 * 取得对象的主键名.
	 */
	public String getIdName() {
		ClassMetadata meta = getSessionFactory().getClassMetadata(entityClass);
		return meta.getIdentifierPropertyName();
	}

	/**
	 * 判断对象的属性值在数据库内是否唯一.
	 * 
	 * 在修改对象的情景下,如果属性新修改的值(value)等于属性原来的值(orgValue)则不作比较.
	 */
	public boolean isPropertyUnique(final String propertyName, final Object newValue, final Object oldValue) {
		if (newValue == null || newValue.equals(oldValue)) {
			return true;
		}
		Object object = findUniqueBy(propertyName, newValue);
		return (object == null);
	}

	@Override
	public void update(T object) {
		getSession().update(object);
	}

	@SuppressWarnings("unchecked")
	@Override
	public T load(ID id) {
		return (T) getSession().load(this.entityClass, id);
	}
	
	/**
	 * 将list转化为数组
	 * @param list
	 * @return
	 */
	protected Criterion[] list2Array(List<Criterion> list){
		if(list == null){
			return new Criterion[0];
		}
		Criterion[] result = new Criterion[list.size()];
		for(int i = 0; i < list.size(); i++){
			result[i] = list.get(i);
		}
		return result;
	}

	@Override
	public void afterPropertiesSet() throws Exception {
		templateCache = new HashMap<String, StatementTemplate>();
		if(this.dynamicStatementBuilder == null){
			this.dynamicStatementBuilder = new NoneDynamicHibernateStatementBuilder();
		}
		dynamicStatementBuilder.init();
		Map<String,String> namedHQLQueries = dynamicStatementBuilder.getNamedHQLQueries();
		Map<String,String> namedSQLQueries = dynamicStatementBuilder.getNamedSQLQueries();
		Configuration configuration = new Configuration();
		configuration.setNumberFormat("#");
		StringTemplateLoader stringLoader = new StringTemplateLoader();
		for(Entry<String, String> entry : namedHQLQueries.entrySet()){
			stringLoader.putTemplate(entry.getKey(), entry.getValue());
			templateCache.put(entry.getKey(), new StatementTemplate(StatementTemplate.TYPE.HQL,new Template(entry.getKey(),new StringReader(entry.getValue()),configuration)));
		}
		for(Entry<String, String> entry : namedSQLQueries.entrySet()){
			stringLoader.putTemplate(entry.getKey(), entry.getValue());
			templateCache.put(entry.getKey(), new StatementTemplate(StatementTemplate.TYPE.SQL,new Template(entry.getKey(),new StringReader(entry.getValue()),configuration)));
		}
		configuration.setTemplateLoader(stringLoader);
	}
	
	protected String processTemplate(StatementTemplate statementTemplate,Map<String, ?> parameters){
		StringWriter stringWriter = new StringWriter();
		try {
			statementTemplate.getTemplate().process(parameters, stringWriter);
		} catch (Exception e) {
			LOGER.error("处理DAO查询参数模板时发生错误:{}",e.toString());
			throw new SysException(e);
		}
		return stringWriter.toString();
	}
}
我们的SimpleHibernateDAO实现了InitializingBean,在其afterProperties方法中我们将调用DynamicHibernateStatementBuilder把语句缓存起来
上层方法调用示例-这个已经非常类似ibatis了
	public List<Resource> getDescendants(Long userId,String code) {
		Map<String, Object> values = new HashMap<String, Object>();
		values.put("userId", String.valueOf(userId));
		values.put("code", code);
		values.put("type", String.valueOf(ResourceTypeEnum.URL_RESOURCE.getType()));
		values.put("status", String.valueOf(ResourceStatusEnum.ACTIVE.getStatus()));
		return this.findByNamedQuery(new ResourceRowMapper(),"resource.getDescendants", values);
	}

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