EntityManager
在使用持久化工具的时候,一般都有一个对象来操作数据库,在原生的Hibernate中叫做Session,在 JPA 中叫做EntityManager,在MyBatis中叫做SqlSession,通过这个对象来操作数据库。
EntityManager是 JPA 中用于增删改查的接口,连接内存中的 java 对象和数据库的数据存储。Hibernate EntityManager是围绕提供JPA编程接口实现的Hibernate Core的一个包装,支持JPA实体实例的生命周期,并允许用标准的Java Persistence查询语言编写查询。
EntityManager称为实体管理器,它由EntityManagerFactory所创建。EntityManagerFactory,作为EntityManager的工厂,包含有当前O-R映射的元数据信息,每个EntityManagerFactory,可称为一个持久化单元(PersistenceUnit),每个持久化单元可认为是一个数据源的映射(所谓数据源,可理解为一个数据库,可以在应用服务器中配置多个数据源,同时使用不同的PersistenceUnit来映射这些数据源,从而能够很方便的实现跨越多个数据库之间的事务操作!)
PersistenceContext,称为持久化上下文,它一般包含有当前事务范围内的,被管理的实体对象(Entity)的数据。每个EntityManager,都会跟一个PersistenceContext相关联。PersistenceContext中存储的是实体对象的数据,而关系数据库中存储的是记录,EntityManager正是维护这种OR映射的中间者,它可以把数据从数据库中加载到PersistenceContext中,也可以把数据从PersistenceContext中持久化到数据库,EntityManager通过Persist、merge、remove、refresh、flush等操作来操纵PersistenceContext与数据库数据之间的同步!
EntityManager是应用程序操纵持久化数据的接口。它的作用与hibernate session类似。为了能够在一个请求周期中使用同一个session对象,在hibernate的解决方案中,提出了currentSession的概念,hibernate中的current session,可以跟JTA事务绑定,也可以跟当前线程绑定。在hibernate中,session管理着所有的持久化对象的数据。而在EJB3中,EntityManager管理着PersistenceContext,PersistenceContext正是被管理的持久化对象的集合。
以下是基于项目中使用来说的
依赖
<spring-boot.version>2.5.6</spring-boot.version>
<hibernate-types-52.version>2.14.0</hibernate-types-52.version>
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<!-- hibernate支持配置 -->
<dependency><groupId>org.hibernate</groupId><artifactId>hibernate-core</artifactId>
</dependency>
<dependency><groupId>org.hibernate</groupId><artifactId>hibernate-entitymanager</artifactId>
</dependency>
<dependency><groupId>org.hibernate</groupId><artifactId>hibernate-ehcache</artifactId>
</dependency>
<dependency><groupId>com.vladmihalcea</groupId><artifactId>hibernate-types-52</artifactId><version>${hibernate-types-52.version}</version>
</dependency>
<!-- hibernate支持配置 -->
配置
spring.datasource.url=jdbc:postgresql://localhost:5432/demo
spring.datasource.username=demo
spring.datasource.password=demo
spring.datasource.driver-class-name=org.postgresql.Driver
#该选项用来验证数据库连接的有效性。如果您的驱动程序支持JDBC4,我们强烈建议您不要设置此属性
spring.datasource.hikari.connection-test-query=SELECT 1
#池中最大连接数,包括闲置和使用中的连接
spring.datasource.hikari.maximum-pool-size=100
#自动提交从池中返回的连接
spring.datasource.hikari.auto-commit=true
#池中维护的最小空闲连接数
spring.datasource.hikari.minimum-idle=10
#连接允许在池中闲置的最长时间
spring.datasource.hikari.idle-timeout=30000
#连接池的用户定义名称,主要出现在日志记录和JMX管理控制台中以识别池和池配置
spring.datasource.hikari.pool-name=DatebookHikariCP
#池中连接最长生命周期
spring.datasource.hikari.max-lifetime=1800000
#等待来自池的连接的最大毫秒数
spring.datasource.hikari.connection-timeout=30000spring.jpa.database=POSTGRESQL
spring.jpa.properties.hibernate.current_session_context_class=org.springframework.orm.hibernate5.SpringSessionContext
#spring.jpa.properties.hibernate.current_session_context_class=thread
spring.jpa.properties.hibernate.hbm2ddl.auto=update//自动创建表
#spring.jpa.properties.hibernate.default_schema=mss
spring.jpa.properties.hibernate.dialect=com.xysd.common.utils.AdvancedPostgreSQLDialect
spring.jpa.properties.hibernate.show_sql=false
spring.jpa.properties.hibernate.format_sql=false
spring.jpa.properties.hibernate.use_sql_comments=false
spring.jpa.properties.hibernate.jdbc.batch_size=500
spring.jpa.properties.hibernate.default_batch_fetch_size=160
spring.jpa.properties.hibernate.max_fetch_depth=3
spring.jpa.properties.hibernate.batch_fetch_style=DYNAMIC
spring.jpa.properties.hibernate.jdbc.fetch_size=500
spring.jpa.properties.hibernate.cache.use_second_level_cache=false
spring.jpa.properties.hibernate.cache.region.factory_class=org.hibernate.cache.ehcache.EhCacheRegionFactory
spring.jpa.properties.hibernate.cache.use_query_cache=false
spring.jpa.properties.hibernate.order_updates=true
spring.jpa.properties.hibernate.query.substitutions=true 1,false 0
#避免KingBase报createClob 错误
spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation=true
SpringSessionContext
AdvancedPostgreSQLDialect
public class AdvancedPostgreSQLDialect extends PostgreSQL10Dialect {public AdvancedPostgreSQLDialect(){super();this.registerColumnType(Types.CLOB, "text");this.registerColumnType(Types.BOOLEAN, "bit");this.registerHibernateType(Types.ARRAY, StandardBasicTypes.CHARACTER_ARRAY.getName());//支持jsonb extAttr属性this.registerColumnType(Types.OTHER, "jsonb" );}}
支持JPA:LocalContainerEntityManagerFactoryBean—>得到EntityManager—>得到session
不支持JPA:LocalSessionFactoryBean—>得到session
LocalContainerEntityManagerFactoryBean与LocalSessionFactoryBean
封装JPA操作
@SuppressWarnings("rawtypes")
public class JpaQueryBuilder{static boolean isMonitorPerformance() {return false;}/*** 创建query* 通过params设置query查询参数* @param hql* @param params*/static Query createHQLQueryByParams(Session session, String hql, Object... params){Query query = session.createQuery(hql);setParamsWithQuery(query, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}/*** 创建query* 通过params设置query查询参数* @param <T>* @param hql* @param params*/static <T> Query<T> createHQLQueryByParams(Session session, Class<T> resultType, String hql,Object... params){Query<T> query = session.createQuery(hql,resultType);setParamsWithQuery(query, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}/*** 创建query* 通过params设置query查询参数* @param hql* @param params*/static Query createHQLQueryByMapParams(Session session, String hql, Map<String,Object> params){Query query = session.createQuery(hql);setNamedParamsWithQuery(query, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}/*** 创建query* 通过params设置query查询参数* @param <T>* @param hql* @param params*/static <T> Query<T> createHQLQueryByMapParams(Session session, Class<T> resultType, String hql,Map<String,Object> params){Query<T> query = session.createQuery(hql,resultType);setNamedParamsWithQuery(query, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}/*** 创建query 带分页* 通过params设置query查询参数* @param hql* @param params*/static Query createPageHQLQueryByMapParams(Session session, String hql, int pageNo, int pageSize,Map<String,Object> params){Query query = session.createQuery(hql);setNamedParamsWithQuery(query, params);int startIndex=(pageNo-1)*pageSize;query.setFirstResult(startIndex).setMaxResults(pageSize);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}/*** 创建query 带分页* 通过params设置query查询参数* @param <T>* @param hql* @param params*/static <T> Query<T> createPageHQLQueryByMapParams(Session session, Class<T> resultType, String hql,int pageNo, int pageSize, Map<String,Object> params){Query<T> query = session.createQuery(hql,resultType);setNamedParamsWithQuery(query, params);int startIndex=(pageNo-1)*pageSize;query.setFirstResult(startIndex).setMaxResults(pageSize);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}/*** 创建NativeQuery* @param sql* @param params 参数为数组*/static NativeQuery createSQLQueryByParams(Session session, String sql, Object... params){NativeQuery query = session.createNativeQuery(sql);setParamsWithQuery(query, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(NativeQuery.class, sql,query);}return query;}/*** 创建NativeQuery* @param <T>* @param sql* @param params 参数为数组*/static <T> NativeQuery<T> createSQLQueryByParams(Session session, Class<T> resultType, String sql,Object... params){NativeQuery<T> query = session.createNativeQuery(sql,resultType);setParamsWithQuery(query, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(NativeQuery.class, sql,query);}return query;}/*** 创建NativeQuery* @param sql* @param params*/static NativeQuery createSQLQueryByMapParams(Session session, String sql, Map<String,Object> params){NativeQuery query = session.createNativeQuery(sql);setNamedParamsWithQuery(query, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(NativeQuery.class, sql,query);}return query;}/*** 创建NativeQuery* @param <T>* @param sql* @param params*/static <T> NativeQuery<T> createSQLQueryByMapParams(Session session, Class<T> resultType, String sql,Map<String,Object> params){NativeQuery<T> query = session.createNativeQuery(sql,resultType);setNamedParamsWithQuery(query, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(NativeQuery.class, sql,query);}return query;}/*** 创建NativeQuery 带分页* @param pageNo* @param params*/static NativeQuery createPageSQLQueryByMapParams(Session session, String sql, int pageNo, int pageSize,Map<String,Object> params){NativeQuery query = session.createNativeQuery(sql);setNamedParamsWithQuery(query, params);int startIndex=(pageNo-1)*pageSize;query.setFirstResult(startIndex).setMaxResults(pageSize);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(NativeQuery.class, sql,query);}return query;}/*** 创建NativeQuery 带分页* @param <T>* @param sql* @param params*/static <T> NativeQuery<T> createPageSQLQueryByMapParams(Session session, Class<T> resultType, String sql,int pageNo, int pageSize, Map<String,Object> params){NativeQuery<T> query = session.createNativeQuery(sql,resultType);setNamedParamsWithQuery(query, params);int startIndex=(pageNo-1)*pageSize;query.setFirstResult(startIndex).setMaxResults(pageSize);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(NativeQuery.class, sql,query);}return query;}//设置参数private static void setParamsWithQuery(Query query, Object... params) {if (params==null||params.length==0) {return;}for(int i=0;i<params.length;i++){query.setParameter(i,params[i]);}}//设置参数private static void setNamedParamsWithQuery(Query query, Map<String, Object> params) {if (params==null||params.size()==0) {return;}for(Map.Entry<String,Object> entry:params.entrySet()){Object paramKey = entry.getKey();Object paramValue = entry.getValue();if(paramValue instanceof List){query.setParameterList((String)paramKey, (List)paramValue);}else if(paramValue instanceof String[]){query.setParameterList((String)paramKey, (String[])paramValue);}else if(paramValue instanceof Object[]){query.setParameterList((String)paramKey, (Object[])paramValue);}else if(paramValue instanceof Collection){query.setParameterList((String)paramKey, (Collection)paramValue);}else{query.setParameter((String)paramKey, paramValue);}}}}
对外提供的服务
@SuppressWarnings({"rawtypes","unchecked"})
public abstract class JpaHibernateRepository{protected Logger logger = LogManager.getLogger(this.getClass());@Autowired@PersistenceContextprivate EntityManager em;protected EntityManager getEm(){return em;}/*** 根据jpa EntityManager 获取hibernate session* @return*/protected Session getSession(){return (Session) getEm().getDelegate();}private boolean isMonitorPerformance() {return true;}/*** 创建query* 通过params设置query查询参数* @param hql* @param params*/protected Query createHQLQueryByParams(String hql,Object... params){Query query = JpaQueryBuilder.createHQLQueryByParams(getSession(), hql, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}/*** 创建query* 通过params设置query查询参数* @param <T>* @param hql* @param params*/protected <T> Query<T> createHQLQueryByParams(Class<T> resultType,String hql,Object... params){Query<T> query = JpaQueryBuilder.createHQLQueryByParams(getSession(), resultType, hql, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class,hql, query);}return query;}/*** 创建query* 通过params设置query查询参数* @param hql* @param params*/protected Query createHQLQueryByMapParams(String hql,Map<String,Object> params){Query query = JpaQueryBuilder.createHQLQueryByMapParams(getSession(), hql, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;} /*** 创建query* 通过params设置query查询参数* @param <T>* @param hql* @param params*/protected <T> Query<T> createHQLQueryByMapParams(Class<T> resultType,String hql,Map<String,Object> params){Query<T> query = JpaQueryBuilder.createHQLQueryByMapParams(getSession(), resultType, hql, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}/*** 创建query 带分页* 通过params设置query查询参数* @param hql* @param params*/protected Query createPageHQLQueryByMapParams(String hql,int pageNo,int pageSize,Map<String,Object> params){Query query = JpaQueryBuilder.createPageHQLQueryByMapParams(getSession(), hql, pageNo, pageSize, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}/*** 创建query 带分页* 通过params设置query查询参数* @param <T>* @param hql* @param params*/protected <T> Query<T> createPageHQLQueryByMapParams(Class<T> resultType,String hql,int pageNo,int pageSize,Map<String,Object> params){Query<T> query = JpaQueryBuilder.createPageHQLQueryByMapParams(getSession(), resultType, hql, pageNo, pageSize, params);if(isMonitorPerformance()) {return QueryProxy.newProxyQuery(Query.class, hql,query);}return query;}//批量执行sql更新protected int batchUpdateSql(final String sql,final List<Object[]> batchParams){long start = System.currentTimeMillis();final BatchUpdatedResult updateResult = new BatchUpdatedResult();this.getSession().doWork(new Work() {@Overridepublic void execute(Connection conn) throws SQLException {PreparedStatement ps = null ;try{ps = conn.prepareStatement(sql);for(Object[] params : batchParams){if(params == null){continue;}for(int i=0;i<params.length;i++){Object p = params[i];if(p == null){ps.setNull(i+1,Types.VARCHAR);}else if( p instanceof String){String pstr = (String)p;ps.setString(i+1, pstr);}else if(p instanceof Integer){int n = (Integer)p;ps.setInt(i+1, n);}else if(p instanceof Date){Date d = (Date)p;ps.setTimestamp(i+1, new Timestamp(d.getTime()));}else if(p instanceof Long){Long d = (Long)p;ps.setLong(i+1, d);}else if(p instanceof Byte){Byte d = (Byte)p;ps.setByte(i+1, d);}else if(p instanceof Boolean){Boolean d = (Boolean)p;ps.setBoolean(i+1, d);}else if(p instanceof Double){Double d = (Double)p;ps.setDouble(i+1, d);}else if(p instanceof BigDecimal){BigDecimal d = (BigDecimal)p;ps.setBigDecimal(i+1, d);}else if(p instanceof Float){Float d = (Float)p;ps.setFloat(i+1, d);}else{throw new RuntimeException("未识别的参数类型:"+p.getClass());}}ps.addBatch();}int[] updateds = ps.executeBatch();for(int update:updateds) {updateResult.addUpdated(update);}}finally{if(ps!=null){ps.close();}}}});logger.info("耗时["+(System.currentTimeMillis()-start)+"]毫秒批量执行SQL:"+sql+"");return updateResult.updated;}//批量执行sql更新protected int batchUpdateSql(final String sql,final List<Object[]> batchParams,int[] sqlTypes){long start = System.currentTimeMillis();final BatchUpdatedResult updateResult = new BatchUpdatedResult();this.getSession().doWork(new Work() {@Overridepublic void execute(Connection conn) throws SQLException {PreparedStatement ps = null ;try{ps = conn.prepareStatement(sql);for(Object[] params : batchParams){if(params == null){continue;}if(sqlTypes==null || sqlTypes.length!=params.length){throw new IllegalArgumentException("sqlTypes.length must be equal to params.length");}for(int i=0;i<params.length;i++){Object p = params[i];if(p == null){ps.setNull(i+1,sqlTypes[i]);}else if( p instanceof String){String pstr = (String)p;ps.setString(i+1, pstr);}else if(p instanceof Integer){int n = (Integer)p;ps.setInt(i+1, n);}else if(p instanceof Date){Date d = (Date)p;ps.setTimestamp(i+1, new Timestamp(d.getTime()));}else if(p instanceof Long){Long d = (Long)p;ps.setLong(i+1, d);}else if(p instanceof Byte){Byte d = (Byte)p;ps.setByte(i+1, d);}else if(p instanceof Boolean){Boolean d = (Boolean)p;ps.setBoolean(i+1, d);}else if(p instanceof Double){Double d = (Double)p;ps.setDouble(i+1, d);}else if(p instanceof BigDecimal){BigDecimal d = (BigDecimal)p;ps.setBigDecimal(i+1, d);}else if(p instanceof Float){Float d = (Float)p;ps.setFloat(i+1, d);}else{throw new RuntimeException("未识别的参数类型:"+p.getClass());}}ps.addBatch();}int[] updateds = ps.executeBatch();for(int update:updateds) {updateResult.addUpdated(update);}}finally{if(ps!=null){ps.close();}}}});logger.info("耗时["+(System.currentTimeMillis()-start)+"]毫秒批量执行SQL:"+sql+"");return updateResult.updated;}/*** 安全获取实体* @param <T>* @param entityClass* @param id* @return*/public <T> T safeGet(Class<T> entityClass, Serializable id) {if(id==null) return null;if((id instanceof String)&&StringUtils.isBlank((String)id)) {return null;}return this.getSession().get(entityClass, id);}/*** 根据Ids查找entity列表* @param entityClass* @param orderedIds* @return*/public <T> List<T> findByOrderedIds(Class<T> entityClass,Collection<String> orderedIds,String... loadFetchs){List<T> result = new ArrayList<T>();if(orderedIds == null || orderedIds.size() == 0 ){return result;}List<List<String>> splittedIdsList = Utils.splitToFixedList(orderedIds, 800);Map<String, T> entityMap = new HashMap<String, T>();String hql="select o from "+entityClass.getName()+" o ";if(loadFetchs!=null) {for (int i=0;i<loadFetchs.length;i++) {hql=hql+"left join fetch o."+loadFetchs[i]+" o"+i+" ";}}hql=hql+"where o.id in (:ids)";for(List<String> ids : splittedIdsList){List<T> entities = this.createHQLQueryByMapParams(entityClass, hql,Utils.buildMap("ids",ids)).list();for(T t : entities){String id =((IEntity)t).getId();entityMap.put(id, t);}}for(String id : orderedIds){if(entityMap.containsKey(id)){result.add(entityMap.get(id));}}return result;}
}
使用
//更多使用自行参考
@Repository
public class CommonRepositoryHibernate extends JpaHibernateRepository {//构建当前年获取数据public List<DateRec> getHolidayByYear(Date year) {String hql = "select d from " + DateRec.class.getName() + " d where d.valid = 1 and dateTime >= :dateTime ";List<DateRec> holidays = this.createHQLQueryByMapParams(DateRec.class, hql, Utils.buildMap("dateTime", year)).list();if (holidays == null) holidays = new ArrayList<>();return holidays;}//根据主键获取实体对象public DateRec getDateRecById(String id) {DateRec dateRec = this.safeGet(DateRec.class, id);return dateRec;}//根据前端参数构建sqlpublic List<DateRec> getDateRecBy(Map<String, Object> params) {StringBuffer sql = new StringBuffer();sql.append(" select id from t_date_rec d where d.valid = 1 ");if (params.get("ids") != null) {sql.append(" and d.id in (:ids) ");}if (params.get("dateTypes") != null) {sql.append(" and d.date_type in (:dateTypes) ");}List<String> ids = this.createSQLQueryByMapParams(sql.toString(), params).list();if (CollectionUtils.isEmpty(ids)) return new ArrayList<>();List<DateRec> recs = this.findByOrderedIds(DateRec.class, ids);if (recs == null) recs = new ArrayList<>();return recs;}}