Question

jsp中比如一条信息的标题是这样取得：${content.title}。 怎么截取前面20个字。

JS中很简单，str.substring(0,20)即可。求教JSP中怎么截取的！！

Answer 1

Jsp里面：
<c:choose>
<c:when test="${signalList.SIGNALCOMMENTLESSORMORE eq 'less'}">
<td style="word-break: break-all;">
${signalList.SIGNALCOMMENT}
</td>
</c:when>
<c:when test="${signalList.SIGNALCOMMENTLESSORMORE eq 'more'}">
<td style="word-break: break-all; "id="signalCommentGoGoGoParent:+${pageSize*(pageNeeded-1)+s.index+1}">
${signalList.SIGNALCOMMENTGOGOGO}
<img onclick='signalCommentAll(this)' id="signalCommentGoGoGo:+${pageSize*(pageNeeded-1)+s.index+1}"/>
</td>
<td style="word-break: break-all; display: none;" id="signalCommentParent:+${pageSize*(pageNeeded-1)+s.index+1}">
${signalList.SIGNALCOMMENT}
<img onclick='signalCommentShort(this)' id="signalComment:+${pageSize*(pageNeeded-1)+s.index+1}"/>
</td>
</c:when>
</c:choose>

Js里面：
<script>
function signalCommentShort(obj) {
var c=obj.id.toString().split(":");
document.getElementById('signalCommentParent:'+c[1]).style.display='none';
document.getElementById('signalCommentGoGoGoParent:'+c[1]).style.display='block';
}
function signalCommentAll(obj) {
var c=obj.id.toString().split(":");
document.getElementById('signalCommentGoGoGoParent:'+c[1]).style.display='none';
document.getElementById('signalCommentParent:'+c[1]).style.display='block';
}
</script>

Sqlmaps里面：
select
c.signal_comment as signalComment,
substr(c.signal_comment, 1, 20) || '...' as signalCommentGoGoGo,
case
when length(c.signal_comment) < = 20 then
'less'
else
'more'
end as signalCommentLessOrMore
from jqy.tzjc_t_signal_comment c

Answer 2

如果你想在jsp中使用EL实现你所说的功能是不可能的，EL不支持方法调用，如果你不使用ognl 那就在显示数据之前在业务层处理好它吧