Java 基础代码,初学者小白求大神

private void huSelect() throws Exception {
		// TODO Auto-generated method stub
		System.out.println("输入要查询的户(门)编号:");		
		int hid = input.nextInt();		
		List list = sc.huselect(hid);		
		if(list.size() == 0) {
			System.out.println("该户(门)不存在!");
			return;
		}
		for (int i = 0; i < list.size(); i++) {
			Hu h = (Hu)list.get(i);
			System.out.println(h);
		}
		
	}

public List huselect(int hid) throws Exception {
		// TODO Auto-generated method stub
		Socket sck = new Socket("localhost", 10001);		
		DataOutputStream dout = new DataOutputStream(sck.getOutputStream());
		dout.writeInt(5);		
		//发送参数到服务端
		DataOutputStream dout2 = new DataOutputStream(sck.getOutputStream());
		dout2.writeInt(hid);	 	
		//接收服务端传回的信息
		ObjectInputStream oin = new ObjectInputStream(sck.getInputStream());
		List list = (List) oin.readObject();
		
		oin.close();
		dout2.close();
		dout.close();
		sck.close();
		return list;
	}

private void huselect() throws Exception {
		// TODO Auto-generated method stub
		DataInputStream din = new DataInputStream(sck.getInputStream());
		int hid = din.readInt();
		List list = hdao.selectOne(hid);
		//发送客户端
		ObjectOutputStream out = new ObjectOutputStream(sck.getOutputStream());
		out.writeObject(list);
		
		out.close();
		din.close();
	}

public List selectOne(int hid) throws Exception {
		Class.forName("com.mysql.jdbc.Driver");
		Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/shoulouchu", "root", "mysql");
		String sql = "select * from hu where hid=?";
		PreparedStatement ps = con.prepareStatement(sql);
		ps.setInt(1, hid);
		List list = new ArrayList();						
		ResultSet rs = ps.executeQuery();		 
		while(rs.next()) {
			int lid = rs.getInt(1);
			int hdanyuan = rs.getInt(2);
			int hlouceng = rs.getInt(3);
			
			int hstate = rs.getInt(5);
			Hu h = new Hu(lid, hdanyuan, hlouceng, hid, hstate);
			list.add(h);
		}
		con.close();
		return list;
	}

 

总是报错,求大神

java.lang.ClassCastException: java.util.ArrayList cannot be cast to com.heimao.model.Hu
操作有误!
1、户(门)查询;2、户(门)展示;3、户(门)新增;4、退出;
    at com.heimao.ctrl.ShoulcCtrl.huselect(ShoulcCtrl.java:105)
    at com.heimao.view.HuView.huSelect(HuView.java:130)
    at com.heimao.view.HuView.menu(HuView.java:23)
    at com.heimao.view.AdminView.menu(AdminView.java:31)
    at com.heimao.view.ClientMain.main(ClientMain.java:37)

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xiaojinli666
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2020/11/29 22:39
  • java
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