Java为什么显示不出文本框

Question

package exam.pengbozuishuai;

import java.awt.GridLayout;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class SystemExam extends JFrame {
	
	JTextField dormitory,number,name,sex,age,clas;
	
	public SystemExam() {
		this.setTitle("宿舍成员管理系统");
		this.setSize(400, 400);
		
		dormitory = new JTextField(6);
		JPanel j1 = new JPanel();
		JLabel j1Labe1 = new JLabel("宿舍号:");
		j1.add(j1Labe1);
		j1.add(dormitory);
		
		
		
		
		number = new JTextField(6);
		JPanel j2 = new JPanel();
		JLabel j1Labe2 = new JLabel("学号:");
		j2.add(j1Labe2);
		j2.add(number);
		
		
		name = new JTextField(6);
		JPanel j3 = new JPanel();
		JLabel j1Labe3 = new JLabel("姓名:");
		j3.add(j1Labe3);
		j3.add(name);
		
		
		sex = new JTextField(6);
		JPanel j4 = new JPanel();
		JLabel j1Labe4 = new JLabel("性别:");
		j4.add(j1Labe4);
		j4.add(sex);
		
		
		age = new JTextField(6);
		JPanel j5 = new JPanel();
		JLabel j1Labe5 = new JLabel("年龄:");
		j5.add(j1Labe5);
		j5.add(age);
		
		
		JLabel j1Labe6 = new JLabel("班级:");
		JPanel j6 = new JPanel();
		clas = new JTextField(6);
		j6.add(j1Labe6);
		j6.add(dormitory);
		
		
		this.setLayout(new GridLayout(8, 1));
		this.add(j1);
		this.add(j2);
		this.add(j3);
		this.add(j4);
		this.add(j5);
		this.add(j6);
		this.setVisible(true);
		
		
	}
	
	
	public static void main(String[] args) {
		new SystemExam();
	}

}

为啥宿舍号后面没有文本框。。。。。

Answer 1