Hibernate命名查询顺序依据参数

Question

嗨,任何人都可以指出我们如何将order by子句作为命名参数传递给hql

例如:

作品:

select tb from TransportBooking as tb

and TIMESTAMP(tb.bookingDate, tb.bookingTime) >= current_timestamp() order by tb.bookingDate

不起作用:

select tb from TransportBooking as tb

and TIMESTAMP(tb.bookingDate, tb.bookingTime) >= current_timestamp() order by :order

Answer 1

不支持,输入参数仅允许在WHERE和HAVING子句中使用,并且不能使用该ORDER BY子句的参数.或者,如果我改写,您不能使用列的参数,只能使用值.那么,要么:

• 尽可能多地命名查询排序顺序
• 将排序字符串连接到查询字符串
• 使用条件查询

Answer 2

尝试存储不带order by子句的命名查询,获取查询字符串并在运行时添加order by子句.

Brian Fields在他的博客中解释了这一点:http: //brainfields.blogspot.com/2009/08/order-by-in-hibernate-named-queries.html

我已经为我的项目打包了这个想法:

private static final Pattern badQueryPattern = Pattern.compile("[^\\p{ASCII}]*");

public static String getNamedQueryString(EntityManager em, String queryName) throws SQLException {
    Query tmpQuery = em.createNamedQuery(queryName);
    SQLQuery sqlQuery = tmpQuery.unwrap(SQLQuery.class);
    String queryString = sqlQuery.getQueryString();
    if (badQueryPattern.matcher(queryString).matches()) {
        throw new SQLException("Bad query string.");
    }

    return queryString;
}


public static Query getNamedQueryOrderedBy(EntityManager em, String queryName, Map<String, Boolean> columnNames) throws SQLException {

    StringBuilder sb = new StringBuilder();
    sb.append(ORDER_BY_CLAUSE_START);

    int limit = columnNames.size();
    int i = 0;
    for (String columnName: columnNames.keySet()) {
        sb.append(columnName);

        if (columnNames.get(columnName))
            sb.append(" ASC");
        else
            sb.append(" DESC");

        if (i != (limit - 1)) {
            sb.append(", \n");
        }
    }
    Query jpaQuery = em.createNativeQuery( getNamedQueryString(em, queryName)
                + sb.toString() 
                );

    return jpaQuery;
}