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hkliya
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hibernate分页代码

    博客分类:
  • j2ee
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	public String getLimitString(String sql, boolean hasOffset) {
		
		sql = sql.trim();
		boolean isForUpdate = false;
		if ( sql.toLowerCase().endsWith(" for update") ) {
			sql = sql.substring( 0, sql.length()-11 );
			isForUpdate = true;
		}
		
		StringBuffer pagingSelect = new StringBuffer( sql.length()+100 );
		if (hasOffset) {
			pagingSelect.append("select * from ( select row_.*, rownum rownum_ from ( ");
		}
		else {
			pagingSelect.append("select * from ( ");
		}
		pagingSelect.append(sql);
		if (hasOffset) {
			pagingSelect.append(" ) row_ where rownum <= ?) where rownum_ > ?");
		}
		else {
			pagingSelect.append(" ) where rownum <= ?");
		}

		if (isForUpdate) pagingSelect.append(" for update");
		
		return pagingSelect.toString();
	}


代码来自:org.hibernate.dialect.Oracle9Dialect
这里写两个if(hasOffset)是什么道理呢
是不是可以改成:
	if (hasOffset) {
		pagingSelect.append("select * from ( select row_.*, rownum rownum_ from ( ");
		pagingSelect.append(sql);
		pagingSelect.append(" ) row_ where rownum <= ?) where rownum_ > ?");
	}
	else {
		pagingSelect.append("select * from ( ");
		pagingSelect.append(sql);
		pagingSelect.append(" ) where rownum <= ?");
	}
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