jsp自定义标签

---WEB-INF\mytaglib.tld

<?xml version="1.0" encoding="UTF-8" ?> 

<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN" "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd"> 

<taglib> 
<!-- ============== Tag Library Description Elements ============= --> 

<tlibversion>1.2</tlibversion> 
<jspversion>1.1</jspversion> 
<shortname>bean</shortname> 
<uri>http://struts.apache.org/tags-bean</uri> 
<info> 
This tag library contains useful general-purpose tags supporting 
the development of JSP/servlet applications based on the "Model 
2" (MVC based) design pattern. 

WARNING: ALL OF THE TAGS IN THIS LIBRARY ARE DEPRECATED, AND ARE 
MAINTAINED ONLY FOR BACKWARDS COMPATIBILITY. THEY WILL BE 
REMOVED IN A FUTURE VERSION OF STRUTS. 

</info> 

<!-- ===================== Template Tags ====================== --> 
<!-- Custom tags lib --> 
<tag> 
<name>table2</name> 
<tagclass>lee.Table2Tag</tagclass><!-- 指定业务类 --> 
<bodycontent>empty</bodycontent> 
<attribute> 
<name>table</name> 
<required>true</required> 
<rtexprvalue>true</rtexprvalue> 
</attribute> 
</tag> 
</taglib> 

 

 ---业务类Table2Tag.java

package lee; 

import java.io.IOException; 
import java.io.Writer; 
import java.sql.Connection; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
import java.util.Iterator; 

import javax.servlet.jsp.JspException; 
import javax.servlet.jsp.tagext.TagSupport; 

public class Table2Tag extends TagSupport { 

private String table; 

public String getTable() { 
return table; 
} 
public void setTable(String table) { 
this.table = table; 
} 

@Override 
public int doStartTag() throws JspException { 

Writer out=pageContext.getOut(); 
Table2 table2=new Table2(table);//引用类 
Iterator it=table2.getIterator(); 
int num=0; 
try { 
out.write("<style>td{border:1px solid #000000; padding: 3px;}</style>"); 
out.write("<table cellspacing='0' cellpadding='0' border='0' align='center' style=\"text-align: center;border: 1px solid #000000;border-collapse: collapse;\">"); 
out.write("<tr bgColor='9999cc'>"); 

while(it.hasNext()){ 
out.write("<td nowrap><b>&nbsp;"); 
out.write(it.next().toString()); 
out.write("&nbsp;</b></td>"); 
num++; 
} 
out.write("</tr>"); 


String sql="select top 50 * from "+table; 
Connection conn = DbHelper.getconn(); 
Statement stmt=conn.createStatement(); 
ResultSet rs=stmt.executeQuery(sql); 
while(rs.next()){ 
out.write("<tr>"); 
for (int i = 1; i <= num; i++) { 
String clm=rs.getString(i); 
clm=clm==null?"":clm; 
out.write("<td title=\""+clm+"\" nowrap>"); 
out.write(clm.length()>25?clm.substring(0, 25)+"...":clm); 
out.write("</td>"); 
} 
out.write("</tr>"); 
} 
out.write("</table>"); 
DbHelper.closeAll(); 
} catch (IOException e) { 
e.printStackTrace(); 
} catch (ClassNotFoundException e) { 
e.printStackTrace(); 
} catch (SQLException e) { 
e.printStackTrace(); 
} 
return SKIP_BODY; 
} 
} 

 

---引用类Table2.java

package lee; 

import java.io.Serializable; 
import java.sql.Connection; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
import java.util.ArrayList; 
import java.util.Iterator; 
import java.util.List; 

public class Table2 implements Serializable { 


private Iterator iterator; 
private String table; 

public String getTable() { 
return table; 
} 

public void setTable(String table) { 
this.table = table; 
} 

public Iterator getIterator() { 
return iterator; 
} 

public void setIterator(Iterator iterator) { 
this.iterator = iterator; 
} 

public Table2() { 
super(); 
} 

public Table2(String table) { 
super(); 
this.table = table; 

List list=new ArrayList(); 
try { 
String sql="select name from syscolumns Where ID=OBJECT_ID('"+table+"')"; 
Connection conn=DbHelper.getconn(); 
Statement stmt=conn.createStatement(); 
ResultSet rs=stmt.executeQuery(sql); 
while(rs.next()){ 
list.add(rs.getObject("name")); 
} 
} catch (ClassNotFoundException e) { 
e.printStackTrace(); 
} catch (SQLException e) { 
e.printStackTrace(); 
}finally{ 
DbHelper.closeAll(); 
} 
iterator=list.iterator(); 
} 
} 

 

---jsp调用 

<%@ taglib prefix="mytag" uri="/WEB-INF/mytaglib.tld" %> 
<mytag:table2 table="数据库表名"/>