java.lang.IllegalStateException: EntityManager is closed问题解决

妖狐艹你老母 2023-07-13 03:49 2阅读 0赞

报错信息：  
 **   org.springframework.dao.InvalidDataAccessApiUsageException: EntityManager is closed; nested exception is java.lang.IllegalStateException: EntityManager is closed**  
    at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:381)  
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:246)  
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:488)  
    at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59)  
    at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)  
  
  
原因是代码中query有多次读取操作如：**（query.getResultList()）**，query在读取一次之后会自动关闭，

原代码：

public List<Map<String, Object>> selectUserInfo(String userId) {
            StringBuilder sql = new StringBuilder(" select user_id as userId,mobile  ");
            sql.append(" from user_info ");
            sql.append(" where user_id = :userId");
            Query query = entityManager.createNativeQuery(sql.toString());
            query.setParameter("userId", userId);
            if (query.getResultList() != null && query.getResultList().size() > 0) {
                // 将结果转化为 Map<column, value>
                query.unwrap(SQLQuery.class).setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
                return query.getResultList();
            }
            return null;
        }

修改之后：

public List<Map<String, Object>> selectUserInfo(String userId) {
            StringBuilder sql = new StringBuilder(" select user_id as userId,mobile  ");
            sql.append(" from user_info ");
            sql.append(" where user_id = :userId");
            Query query = entityManager.createNativeQuery(sql.toString());
            query.setParameter("userId", userId);
            // 将结果转化为 Map<column, value>
            query.unwrap(SQLQuery.class).setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
            return query.getResultList();
        }

对比可以发现query.getResultList();**查询只触发一次**，就不会出现EntityManager is closed;的问题了，