我要评论假定一个类，类名是etybase，另一个类类名是etytwo，etytwo继承自etybase。现在要求etytwo的属性值从一个etybase中复制过来传统做法是
view code
public void copyety(etybase from, etybase to)
{
to.accstatus = from.accstatus;
to.alarm = from.alarm;
to.alarmtype = from.alarmtype;
to.carnum = from.carnum;
to.devnum = from.devnum;
to.devicenum = from.devicenum;
to.direct = from.direct;
to.drivecode = from.drivecode;
to.gpsdata = from.gpsdata;
to.gpsenvent = from.gpsenvent;
to.gpsodo = from.gpsodo;
to.gpsspeed = from.gpsspeed;
to.gpsstatus = from.gpsstatus;
to.gpsrevtime = from.gpsrevtime;
to.gsmci = from.gsmci;
to.gsmci1 = from.gsmci1;
to.gsmloc = from.gsmloc;
to.gsmloc1 = from.gsmloc1;
to.iseffective = from.iseffective;
to.isjump = from.isjump;
to.isreply = from.isreply;
to.latitude = from.latitude;
to.launchstatus = from.launchstatus;
to.longitude = from.longitude;
to.msgcontent = from.msgcontent;
to.msgexid = from.msgexid;
to.msgid = from.msgid;
to.msglength = from.msglength;
to.msgtype = from.msgtype;
to.nowoverarea = from.nowoverarea;
to.nowstatus = from.nowstatus;
to.oil = from.oil;
to.pulsecount = from.pulsecount;
to.pulseodo = from.pulseodo;
to.pulsespeed = from.pulsespeed;
to.replycontent = from.replycontent;
to.revmsg = from.revmsg;
to.speed = from.speed;
to.status = from.status;
to.temperture = from.temperture;
to.username = from.username;
}
这样子做有几点不好的地方
etybase的属性改变时复制的属性也得改变，耦合较高；
若etybase的属性比较多，那么这个复制方法将显得比较冗长，写的人手累。
如果用反射来做，我是这么做的
view code
public void copyety(etybase from, etybase to)
{
//利用反射获得类成员
fieldinfo[] fieldfroms = from.gettype().getfields();
fieldinfo[] fieldtos = to.gettype().getfields();
int lento = fieldtos.length;
for (int i = 0, l = fieldfroms.length; i < l; i++)
{
for (int j = 0; j < lento; j++)
{
if (fieldtos[j].name != fieldfroms[i].name) continue;
fieldtos[j].setvalue(to, fieldfroms[i].getvalue(from));
break;
}
}
}
反射可以解决上述的两个缺点，当类属性改变或增加时，此复制方法无需改变。当然这是要付出些许运行效率的。
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