新手求助

java.lang.ClassCastException: Bll.EquipmentBll cannot be cast to Modul.Equ
这行显示你EquipmentBll的类型跟Equ的类型之间不能做类型转换。你看一下你那两个东西是怎么定义的

解决方案 »

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package Bll;
import util.DataBase;
import java.sql.*;
public class EquipmentBll {
public EquipmentBll()
{

}
public ResultSet Query(String strWhere)
{
java.sql.ResultSet rt = null;
try
{
  DataBase db = new DataBase();
  String strSql = "  select * from Equipment  a left join js_Dept b on a.xsid=b.D_ID where a.Flag=1 ";
  if(strWhere!=null&&strWhere!="")
  {
    strSql = strSql+strWhere;
  }
  rt = db.Query(strSql);
}
catch(Exception ee )
{
System.out.println("connect db error:"+ee.getMessage());
return null;
}
   return rt;
}

public boolean InsertEqu(Modul.Equ Equ)
{
try
{
DataBase db = new DataBase();
String strSql="insert into Equipment(EquName,Place,House,Port,Factory,EmpName,xsid,Flag)values( "+
             " '"+Equ.getEquName()+"','"+Equ.getPlace()+"','"+Equ.getHouse()+"',"+Equ.getPort()+",'"+Equ.getFactory()+"' "+
             ",'"+Equ.getEmpName()+"','"+Equ.getxsid()+"','1')";
db.execute(strSql);
}
catch(Exception ee )
{
System.out.println("connect db error:"+ee.getMessage());
return false;
}
return true;
}

public boolean UpdateEqu(Modul.Equ Equ,String strID)
{
try
{
DataBase db = new DataBase();
String strSql="Update Equipment set EquName='"+Equ.getEquName()+"',Place='"+Equ.getPlace()+"',House='"+Equ.getHouse()+"',"+
              "Port="+Equ.getPort()+",Factory='"+Equ.getFactory()+"',EmpName='"+Equ.getEmpName()+"',"+
              "xsid='"+Equ.getxsid()+"', where EquID='"+strID+"'"; db.execute(strSql);

}
catch(Exception ee )
{
System.out.println("connect db error:"+ee.getMessage());
return false;
}
return true;
}

public boolean DeleteEqu(String strID)
{
try
{
DataBase db = new DataBase();
String strSql=" update Equipment set Flag=0 where EquID in ("+strID+")";
     db.execute(strSql);
}
catch(Exception ee )
{
System.out.println("connect db error:"+ee.getMessage());
return false;
}
return true;
}

}
package Modul;public class Equ {
    private String EquName;
    private String Place;
    private String House;
    private String Port;
    private String Factory;
    private String EmpName;
    private String CreateDate;
    private String xsid;
        public Equ()
    {

    }

    public void setEquName(String strEquName)
    {
      this.EquName = strEquName;
    }
    public String getEquName()
    {
   return this.EquName;
    }

    public void setPlace(String strPlace)
    {
      this.Place = strPlace;
    }
    public String getPlace()
    {
   return this.Place;
    }

    public void setHouse(String strHouse)
    {
      this.House = strHouse;
    }
    public String getHouse()
    {
   return this.House;
    }

    public void setPort(String strPort)
    {
      this.Port = strPort;
    }
    public String getPort()
    {
   return this.Port;
    }

    public void setFactory(String strFactory)
    {
      this.Factory = strFactory;
    }
    public String getFactory()
    {
   return this.Factory;
    }

    public void setEmpName(String strEmpName)
    {
      this.EmpName = strEmpName;
    }
    public String getEmpName()
    {
   return this.EmpName;
    }

    public void setCreateDate(String strCreateDate)
    {
      this.CreateDate = strCreateDate;
    }
    public String getCreateDate()
    {
   return this.CreateDate;
    }

    public void setxsid(String strxsid)
    {
     this.xsid = strxsid;
    }
    public String getxsid()
    {
     return this.xsid;
    }
}
就是这两个类我没有对他们做类型转换。。只是在Bll类中用到了Equ类。。
<%@page pageEncoding="GB2312"%>
<%@page contentType="text/html; charset=gb2312"%>
<%request.setCharacterEncoding("GB2312");%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>Insert title here</title>
</head>
<body>
  <jsp:useBean id="Equ"  scope="application" class="Modul.Equ"/>
    <jsp:useBean id="Equipment"  scope="application" class="Bll.EquipmentBll"/> <% Equ.setEquName(request.getParameter("strEquname"));
Equ.setPlace(request.getParameter("strPlace"));
Equ.setHouse(request.getParameter("strHouse"));
Equ.setPort(request.getParameter("strPort"));
Equ.setFactory(request.getParameter("strFactory"));
Equ.setEmpName(request.getParameter("strEmpName"));
Equ.setCreateDate(request.getParameter("strCreateDate"));
Equ.setxsid(request.getParameter("select"));
if(Integer.parseInt(request.getParameter("Op"))==2) //修改
  {
    if(Equipment.UpdateEqu(Equ,request.getParameter("ID")))
    {
            out.print("<script>");
             out.print("alert('修改成功！');");
             out.print("history.back();");
             out.print("</script>");
    }
    else
    {
               out.print("<script>");
             out.print("alert('修改失败！');");
             out.print("history.back();");
             out.print("</script>");
    }
  }
  else
  {
    if(Equipment.InsertEqu(Equ))
    {
                 out.print("<script>");
             out.print("alert('保存成功！');");
             out.print("history.back();");
             out.print("</script>");
    }
    else
    {
             out.print("<script>");
             out.print("alert('保存失败！');");
             out.print("history.back();");
             out.print("</script>");
    }
  } %>
</body>
</html>这个就是报错的jsp页面。
<jsp:useBean id="Equipment"  scope="application" class="Bll.EquipmentBll"/>
这两个怎么能转换呢？
那应该怎么写？？？？id不是只是一个名字而已吗？对不起，我以前是做.net的。。刚自学写jsp...里面都有很多.net的痕迹。
<jsp:useBean id="EquipmentBll"  scope="application" class="Bll.EquipmentBll"/>    我改成这样了。。依然报上面的错误。。
去掉<jsp:useBean id="Equipment"  scope="application" class="Bll.EquipmentBll"/>
Equipment。是我要用到的方法，怎么能去掉。。去掉它也报错。去掉Equ不报错还有谁帮我看一下问题没有。。