jsp自定义标签下拉框

package com.soft.test;
 
 import java.sql.*;
 
 import sun.jdbc.odbc.ee.connectionpool;
 
 public class basedao {
     //定义数据源驱动
     private static final string drive="oracle.jdbc.driver.oracledriver";
     //定义连接字符串
     private static final string url="jdbc:oracle:thin:@10.72.240.34:1522:ffv2dev2";
     //用户名
     private static final string uid="produsr";
     //密码
     private static final string pwd="prod_123";
     //获得连接
     public static connection getconnection()
     { 
         connection con=null;
         try {
             //加载驱动
             class.forname(drive);
             //建立连接
             con=drivermanager.getconnection(url,uid,pwd);
         } catch (exception e) {
             e.printstacktrace();
         }
         return con;
     }
     //运行有结果，没有参数的sql语句
     public static resultset resultrunselectsql(string sql)
     {
         connection con=null;
         preparedstatement ps=null;
         resultset res=null;
         try
         {
         con=getconnection();
         ps=con.preparestatement(sql);
         res=ps.executequery();  
         }
         catch(exception e)
         {
             e.printstacktrace();
         }
         return res;
     }
     //执行有结果有参数的sql语句
     public static resultset runselectsql(string sql,object[] params)
     {
         connection con=null;
         preparedstatement pre=null;
         resultset res=null;
         
         try {
             con=getconnection();
             pre=con.preparestatement(sql);
           for(int i=0;i<params.length;i++)
           {
               pre.setobject(i+1, params[i]);
               
           }
           res=pre.executequery();
         } catch (exception e) {
             // todo auto-generated catch block
             e.printstacktrace();
         }
         return res;
     }
     
     //运行没有结果，没有参数的sql语句
     public static boolean runupdatesql(string sql)
     
     {
         connection con=null;
         preparedstatement ps=null;
         resultset res=null;
         try
         {
             con=getconnection();
             ps=con.preparestatement(sql);
             
         ps.executeupdate();
         return true;
             
         }
         catch(exception e)
         {
             e.printstacktrace();
             return false;
         }
         
         
     }
     //执行有结果有参数的sql语句
     public static boolean runupdatesql(string sql,object[] params)
     {
         connection con=null;
         preparedstatement pre=null;
     
         
         try {
             con=getconnection();
             pre=con.preparestatement(sql);
           for(int i=0;i<params.length;i++)
           {
               pre.setobject(i+1, params[i]);
                
           }
           pre.executeupdate();
           return true;
         } catch (exception e) {
             // todo auto-generated catch block
             e.printstacktrace();
             return false;
         }   
     }
 }
 [java]
 package com.soft.test;
 
 import java.io.ioexception;
 import java.sql.connection;
 import java.sql.preparedstatement;
 import java.sql.resultset;
 import java.sql.sqlexception;
 
 import javax.servlet..jspexception;
 import javax.servlet.jsp.jspwriter;
 import javax.servlet.jsp.tagext.tagsupport;
 
 public class mytag extends tagsupport{
     private string tablename;//表明
     private string label;//下拉框要显示的名称
     private string value;//下拉框的值
     private string where;//条件
     private string selectname;//下拉框的名称
     private string selectid;//下拉款的id
 @override
 public int doendtag() throws jspexception {
     // todo auto-generated method stub
     jspwriter out=this.pagecontext.getout();
     string sql="select "+label+","+value+" from "+tablename+" "+where+"";//定义sql语句
     connection conn=basedao.getconnection();
     try {
         preparedstatement ps=conn.preparestatement(sql);
         resultset res=ps.executequery();
         out.print("<select id=\""+selectid+"\" name=\""+selectname+"\">");
         out.print("<option value=\"\">请选择</option>");
         while(res.next()){
             object values=res.getobject(value);
             object labels=res.getobject(label);
             out.print("<option value=\""+values+"\">"+labels+"</option>");
         }
         out.print("</select>");
     } catch (sqlexception e) {
         // todo auto-generated catch block
         e.printstacktrace();
     } catch (ioexception e) {
         // todo auto-generated catch block
         e.printstacktrace();
     }finally{
     
     }
     return super.doendtag();
 }
 public string gettablename() {
     return tablename;
 }
 public void settablename(string tablename) {
     this.tablename = tablename;
 }
 public string getlabel() {
     return label;
 }
 public void setlabel(string label) {
     this.label = label;
 }
 public string getvalue() {
     return value;
 }
 public void setvalue(string value) {
     this.value = value;
 }
 public string getwhere() {
     return where;
 }
 public void setwhere(string where) {
     this.where = where;
 }
 public string getselectname() {
     return selectname;
 }
 public void setselectname(string selectname) {
     this.selectname = selectname;
 }
 public string getselectid() {
     return selectid;
 }
 public void setselectid(string selectid) {
     this.selectid = selectid;
 }
 
 }
 
[java]
 <?xml version="1.0" encoding="utf-8"?>
 <!doctype taglib public "-//sun microsystems, inc.//dtd jsp tag library 1.2//en"
                         "https://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
 <taglib>
  <tlib-version>1.0</tlib-version>
  <jsp-version>1.2</jsp-version>
  <short-name>s</short-name>
  <uri>https://www.574394550.com</uri>
  
  <tag>
  <name>select</name>
  <tag-class>com.soft.test.mytag</tag-class>
  <body-content>empty</body-content>
  <attribute>
  <name>tablename</name>
  <required>true</required>
  </attribute>
  
   <attribute>
  <name>label</name>
  <required>true</required>
  </attribute>
  
    <attribute>
  <name>value</name>
  <required>true</required>
  </attribute>
  
   <attribute>
  <name>where</name>
  <required>true</required>
  </attribute>
  
   <attribute>
  <name>selectname</name>
  <required>true</required>
  </attribute>
  
   <attribute>
  <name>selectid</name>
  <required>true</required>
  </attribute>
  </tag>
 </taglib>
 
[java]
 <%@ page language="java"  pageencoding="gbk"%>
 <%@ taglib uri="" prefix="s" %>
 <%
 string path = request.getcontextpath();
 %>
 <!doctype html public "-//w3c//dtd html 4.01 transitional//en">
 <html>
   <head>
     <title>my jsp 'index.jsp' starting page</title>
   </head>
   
   <body>
     this is my jsp page. <br>
     <s:select selectname="select" selectid="select" label="user_name" value="user_id" tablename="tu_oaf_users" where="where 1=1"/>
   </body>
 </html>
 
 摘自xinghui_liu的专栏