运用类反射机制简化Struts应用程序的开发

Connection conn=DriverManager.getConnection("JDBC URL ");
sql=" select *  from some tables ";
PreparedStatement stmt = conn.prepareStatement(sql);
ResultSet rs = stmt.executeQuery();
ArrayList array=new ArrayList();
while (rs.next()) {
AActionForm actionForm =new AActionForm ();
actionForm.setId(rs.getString("Id"));
actionForm.setName(rs.getString("Name"));           
array.add(actionForm);
}

<logic:present name=" array " scope="request">
<logic:iterate name=" array " id=" array " 
type="com.bhsky.webis.Goods">
<tr align="center"> 
<td class="table2">
<bean:write name=" array " property="goodsid"/>
</td>
<td class="table2">
<bean:write name=" array " property="goodsname"/>
</td>
</tr>
</logic:iterate> 
</logic:present>

package com.bhsky.webis.system;
import org.apache.struts.action.*;
import javax.servlet.http.*;

public class UsersActionForm extends ActionForm {
private String usr_id;
private String usr_name;
public void setUsr_id(String usr_id) {
this.usr_id = usr_id;
}
public String getUsr_id() {
return usr_id;
}
public String getUsr_memo() {
return usr_memo;
}
public void setUsr_name(String usr_name) {
this.usr_name = usr_name;
}
}

///////////////////////////////////////////////////////////////
//Function: 完成ResultSet对象向ArrayList对象为集合的对象的转化
//Para:sql,指定的查询Sql
//Para:className,Sql相对应得JavaBean/FormBean类的名字
//Return:以类className为一条记录的结果集，完成ResultSet对象向
ArrayList对象为集//合的className对象的转化
/////////////////////////////////////////////////////////////////
public ArrayList Select(String sql,String className){
ArrayList paraList=new ArrayList();
try{
if (conn == null){
Connection();
}
PreparedStatement stmt = conn.prepareStatement(sql);
ResultSet rs = stmt.executeQuery();
String recordValue="";
Object c1=null;
paraList=new ArrayList();
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
while (rs.next()){
c1=Class.forName(className).newInstance();
for (int i=1; i<=columnCount; i++) {
if(rs.getString(rsmd.getColumnName(i))!=null){
recordValue=rs.getString(rsmd.getColumnName(i));
}else{
recordValue="";
}
Method 
m=c1.getClass().getMethod(getSetMethodName(rsmd.getColumnName(i)),
new Class[]{recordValue.getClass()});
m.invoke (c1, new Object[]{recordValue});
}
paraList.add(c1);
}
}catch(SQLException ex){      
}catch(ClassNotFoundException e){
}catch(NoSuchMethodException e) {
}catch(InvocationTargetException e){
}catch (IllegalAccessException e){
}catch(InstantiationException e){
} finaly{
closeConnection();
return paraList;
}
}

//Function:取得用户列表
//Para:
//Return:返回用户列表
//////////////////////////////////////////////////////////////////
public ArrayList getUsers(){
ArrayList ret=null;
DatabaseManage db=new DatabaseManage();
String sql=" select usr_id,usr_name "
+" from users " ;
ret=db.Select(sql," com.bhsky. webis.system.UsersActionForm");
return ret;
}

public ActionForward execute(ActionMapping actionMapping, ActionForm actionForm, 
HttpServletRequest request, HttpServletResponse 
httpServletResponse) 
{
/**@todo: complete the business logic here, this is just a skeleton.*/
UsersActionForm uaf=(UsersActionForm)actionForm;
SystemService ubb=new SystemService();
ArrayList userList=ubb.getUsers();
request.setAttribute("userList",userList);
ActionForward actionForward=actionMapping.findForward(url);
return actionForward;
}

<table width="700" class="1" border="1" cellspacing="1" align="center">
<tr>
<td class="list" >用户ID</td>
<td class="list" >姓&#160&#160名</td>
</tr>
<logic:present name="userList" scope="request">
<logic:iterate name="userList" id="userList" 
type="com.bhsky.webis.system.UsersActionForm">
<tr>
<td class="cell1"  height="22"><bean:write name="userList" 
property="usr_id"/></td>
<td class="cell1"  height="22"><bean:write name="userList" 
property="usr_name"/></td>
</tr>
</logic:iterate>
</logic:present>
</table>