NumberField参数传回后台打印为空！后面又报Illegal pattern character

前台：

new Ext.form.DateField({
                id:"jointime",
                name:"jointime",
                width:130,
                fieldLabel:"入会时间",
                maxValue: new Date(),
                minValue:"01/01/2001",
                maxText:"支出日期不能大于{0}",
                minText:"支出日期不能小于{0}",
                allowBlank:false,
                blankText:"入会时间不能为空"
                                                                                    
            })

后台action

public class vipAddAction extends ActionSupport{
    private vipDao vipDao;
    private Vip vip;
    private String vipname;
    private int age;
    private String profession;
    private Date jointime;
    private  boolean success;
    private String msg;
public String execute() throws Exception{
        System.out.println("VIP姓名:"+this.vipname);
        System.out.println("年龄:"+this.age);
        System.out.print("职业:"+this.profession);
        System.out.println("入会时间："+this.jointime);//打印输出为空
                                                                             
                                                                             
        vip=new Vip(this.vipname,this.age
this.jointime,this.profession );
                                                                          
      if(this.vipDao.vipAdd(this.vip)){
          this.success=true;
          this.msg="添加成功";
      }else{
          this.success=false;
          this.msg="添加失败";
      }
      return this.SUCCESS;
                                                                             
    }
}

后来借鉴一个网友的处理：把jointime 设置成String类型，然后再转为Date类型存进数据库

vip=new Vip(this.vipname,this.age,new SimpleDateFormat("D/M/Y").parse(this.jointime),this.profession );

后面竟然还报错：

Illegal pattern character

后面发现一个狗血的原因，竟然是“D/M/Y”小写后就对了！！！！狗血！