DisplayTag应用实践

DisplayTag应用实践

1.表格的显示格式,在css中定义;

css

Property	Default	Valid Values	Description	Can be set using file/setProperty
css.tr.even	even	any valid css class name	css class automatically added to even rows	yes/yes
css.tr.odd	odd	any valid css class name	css class automatically added to odd rows	yes/yes
css.th.sorted	sorted	any valid css class name	css class automatically added to the header of sorted columns	yes/yes
css.th.ascending	order1	any valid css class name	css class automatically added to the header of a column sorted is ascending order	yes/yes
css.th.descending	order2	any valid css class name	css class automatically added to the header of a column sorted is descending order	yes/yes
css.table	none	any valid css class name	css class automatically added to the main table tag	yes/yes
css.th.sortable	none	any valid css class name	css class automatically added to any sortable column	yes/yes

 

2.修改classes/org/displaytag/properties/TableTag.properties,使其符合自己的要求.

basic.empty.showtable = false
basic.show.header = true

# page  |  list
sort.amount = page

export.amount = list
export.decorated = true

paging.banner.group_size = 8
paging.banner.placement = top


css.tr.even = even
css.tr.odd = odd
css.th.sorted = sorted
css.th.ascending = order1
css.th.descending = order2
css.table =
css.th.sortable = sortable

# factory classes  for  extensions
factory.requestHelper = org.displaytag.util.DefaultRequestHelperFactory

# locale provider (Jstl provider by  default )
locale.provider = org.displaytag.localization.I18nJstlAdapter

# locale.resolver (nothing by  default , simply use locale from request)
#locale.resolver =

export.types = csv excel xml pdf

export.csv. class = org.displaytag.export.CsvView
export.excel. class = org.displaytag.export.ExcelView
export.xml. class = org.displaytag.export.XmlView
export.pdf. class = org.displaytag.export.PdfView

export.csv = true
export.csv.label =< span  class = " export csv " > CSV  </ span >
export.csv.include_header = false
export.csv.filename =

export.excel = true
export.excel.label =< span  class = " export excel " > Excel  </ span >
export.excel.include_header = true
export.excel.filename =

export.xml = true
export.xml.label =< span  class = " export xml " > XML  </ span >
export.xml.filename =

export.pdf = false
export.pdf.label =< span  class = " export pdf " > PDF  </ span >
export.pdf.include_header = true
export.pdf.filename =


# messages

basic.msg.empty_list =< center > 对不起,没有符合条件的记录 </ center >
basic.msg.empty_list_row =< tr  class = " empty " >< td colspan = " {0} " > Nothing found to display. </ td ></ tr >
error.msg.invalid_page = invalid page

export.banner =< div  class = " exportlinks " > Export options:  {0} </ div >
export.banner.sepchar =   |

paging.banner.item_name = 记录
paging.banner.items_name = 记录

paging.banner.no_items_found =< span  class = " pagebanner " > 没有任何 {0}  . </ span >
paging.banner.one_item_found =< span  class = " pagebanner " > 搜索到1条 {0}  . </ span >
paging.banner.all_items_found =< span  class = " pagebanner " > 搜索到 < b > {0} </ b > 条 {1} , 当前显示全部 {2} . </ span >
paging.banner.some_items_found =< span  class = " pagebanner " > 搜索到 < b > {0} </ b > 条 {1}  , 当前显示 < b > {2} </ b >  to  < b > {3} </ b > . </ span >

paging.banner.full =< span  class = " pagelinks " > [ < a href = " {1} " > 首页 </ a >/< a href = " {2} " > 上一页 </ a > ]  {0}  [ < a href = " {3} " > 下一页 </ a >/< a href = " {4} " > 末页 </ a > ] </ span >
paging.banner.first =< span  class = " pagelinks " > [首页 / 上一页]  {0}  [ < a href = " {3} " > 下一页 </ a >/< a href = " {4} " > 末页 </ a > ] </ span >
paging.banner.last =< span  class = " pagelinks " > [ < a href = " {1} " > 首页 </ a >/< a href = " {2} " > 上一页 </ a > ]  {0}  [下一页 / 末页] </ span >
paging.banner.onepage =< span  class = " pagelinks " > {0} </ span >

paging.banner.page.selected =< strong > {0} </ strong >
paging.banner.page.link =< a href = " {1} "  title = " Go to page {0} " > {0} </ a >
paging.banner.page.separator = ,

# unused
save.excel.banner =< a href = " {0} "  rel = " external " > save ( {1}  bytes) </ a >
save.excel.filename = export.xls

详情 http://displaytag.sourceforge.net/configuration.html
3.如果TableTag.properties中的相关项包含中文则在web页上会出现乱码,解决方法:下载源码
修改 org.displaytag.properties.TableProperties.java ，把 

   

  private  String getProperty(String key) 
     { 
      return this.properties.getProperty(key); 
    }  

改成 
   

private  String getProperty(String key) 
     { 
        String s = null; 
        try { 
          s = new String(this.properties.getProperty(key).getBytes("8859_1"), "GBK"); 
        }catch(Exception e) { 
          s = null; 
        } 
      return s; 
    }  

4.确保export正确的方法是在web.xml中配置filter:

< filter >  
     < filter - name > ResponseOverrideFilter </ filter - name >  
     < filter - class > org.displaytag.filter.ResponseOverrideFilter </ filter - class >  
</ filter >  
< filter - mapping >  
     < filter - name > ResponseOverrideFilter </ filter - name >  
     < url - pattern >* .jsp </ url - pattern >  
</ filter - mapping >  

详倾参见 http://displaytag.sourceforge.net/export.html
慎用这个filter,尤其是使用tomcat做服务器的朋友,它会使本来就存在的乱码问题更加杂乱,除非改改源码.
5.在jstl中获得数据的方法:

< sql:query var = " query "  dataSource = " ${bookdev} " >  
  select  *   from ebook 
</ sql:query >  

< display - el:table name = " pageScope.query.rows "   />  

用<display-el:table name="${query.rows}" />好像不行;
6.要在外部引用数据,必须在display:table中定义一个id

< display - el:table name = " pageScope.query.rows "  id = " item "   >  
   < display - el:column property = " title "  title = " 题名 "  group = " 1 "  sortable = " true "  headerClass = " sortable " />  
   < display - el:column property = " creator "  title = " 作者 "  group = " 2 "  sortable = " true "  headerClass = " sortable " />  
   < display - el:column property = " format "  title = " 格式 " />  
   < display - el:column title = " 删除 " >< a href = " delete.jsp?id=${item.Id} "  target = " _blank " > 删除 </ a ></ display - el:column >  
</ display - el:table >  

7.问题:如果检索数据库带有中文的字段，在翻页时就查不到记录了?
  这个问题着实把我吓了一大条,因为工程马上就要完了,要是它出了问题,那.....
 好在displaytag比较成熟,用的人比较多,早就有人提出这个问题了,在网上查了一下,原来又是一个编码的问题:
"DisplayTag的默认的URL默认为上一次的URL，如果上一次的URL包含中文的话，则会被进行URLEncode，所以在翻页的时候，又会把进行了URLEncode后的数据再次进行URLEncode，所以翻页就没有数据，因为这部分功能被封装在DisplayTag中"
也提出了解决办法:在Tomcat的server.xml的Connector部分添加URIEncoding="GBK"，
我试了,但是好像不管用,不知道是不是版本不同的缘故,我用的是jakarta-tomcat-5.0.27,应该是比较新的.
考虑到Tomcat5中对Post和Get请求不再采用相同的处理策略,
我把查询表单的form method 由原来的post改为get,翻页就没有问题了,不过这个方法好像蹩脚了点,只能暂时这样了.
在后来的实践中我才发现原来是配置了filter的缘故(见4.确保export正确的方法是在web.xml中配置filter),这个filter打乱了正常的编码.
下面是我的一些测试: (配置了export的filter后)
send.jsp:
<form action="receive.jsp?cs=1" method="POST">
  <input name="key" type="text" value="中文" />
  <input name="sb" value="submit" type="submit"/>
</form>
receive.jsp:cs=${param.cs};key=${param.key}
结果:cs=1,但key=????即使前面用了<%request.setCharacterEncoding("GBK"); %>也不行
只有用<% String key = new String(request.getParameter("key").getBytes("ISO-8859-1"));out.println(key);%>或类似的编码处理才能得到正确结果.
将send.jsp的form method改为get
结果:cs的值为null,key=中文
8.相关资源:
http://www.theserverside.com/news/thread.tss?thread_id=21861