Java中怎么让标签在容器中居中

Question

import javax.swing.*;
import java.awt.*;public class panelcenter extends JFrame { /**
* @param args
*/
JPanel jp = new JPanel();
public panelcenter(){
this.setLayout(new BorderLayout());
JLabel j1 = new JLabel();
j1.setText("第一个swing程序");
jp.add(j1,BorderLayout.CENTER);
this.add(jp);
this.setSize(500, 300);
this.setLocationRelativeTo(null);
this.setVisible(true); }
public static void main(String[] args) {
// TODO Auto-generated method stub
new panelcenter();
}}

Answer 1

增加两句话，我用粗体标出了：

public panelcenter() {
this.setLayout(new BorderLayout());
JLabel j1 = new JLabel();
j1.setHorizontalAlignment(SwingConstants.CENTER);
j1.setText("第一个swing程序");
jp.setLayout(new BorderLayout());
jp.add(j1, BorderLayout.CENTER);
this.add(jp);
this.setSize(500, 300);
this.setLocationRelativeTo(null);
this.setVisible(true);
}

Answer 2

*居中问题(左右):
margin: auto;(左右外边距相同)
width: 120px;(设置宽度)
以上可以用于块级元素

text-align: center;(文字在块中居中)