怎么加上前面的文字？在线等

Question

package six;

import java.awt.*;
import javax.swing.*;
public class FirstSwingApplication extends JFrame{
	
	private JTextField text1,text2,text3;
	private JTextField text_sum;
	private JButton btnresult,btnshow;
	
	public FirstSwingApplication(){
		s();
		d();
		setSize(300,200);
		setTitle("first ");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		pack();
	}
	
	private void s(){
		text1=new JTextField(10);
		text2=new JTextField(10);
		text1=new JTextField(10);
		text_sum=new JTextField(10);
		
		btnresult=new JButton("计算");

		btnshow=new JButton("清楚");

	}
	
	private void d(){
		Container a=getContentPane();
		setLayout(new GridLayout(4,1));
		JPanel pane1=new JPanel();
		pane1.add(text1);
		JPanel pane2=new JPanel();
		pane2.add(text2);
		JPanel pane3=new JPanel();
		pane3.add(text_sum);
		JPanel pane4=new JPanel();
		pane4.add(btnresult);
		JPanel pane5=new JPanel();
		pane5.add(btnshow);
		
		a.add(pane1);
		a.add(pane2);
		a.add(pane3);
		a.add(pane4);
		a.add(pane5);
	}
	
	public static void main(String[] args){
		JFrame.setDefaultLookAndFeelDecorated(true);
		FirstSwingApplication frame=new FirstSwingApplication();
		frame.setVisible(true);

	}
}

Answer 1

import java.awt.*;import javax.swing.*;public class FirstSwingApplication extends JFrame{    private JTextField text1,text2,text3;    private JTextField text_sum;    private JButton btnresult,btnshow;         public  FirstSwingApplication(){        s();        d();        setSize(300,200);        setTitle("first ");        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        pack();    }          private void s(){        text1=new JTextField(10);        text2=new JTextField(10);        text1=new JTextField(10);        text_sum=new JTextField(10);        String str1 ="操作数1";        String str2 ="运算数";        String str3 ="操作数2";        String str4 ="结果";        btnresult=new JButton("计算");         btnshow=new JButton("清楚");     }          private void d(){        Container a=getContentPane();        setLayout(new GridLayout(4,1));        JPanel pane1=new JPanel();   pane1.add(new Label(str1));        pane1.add(text1);        JPanel pane2=new JPanel();     pane2.add(new Label(str2));        pane2.add(text2);        JPanel pane3=new JPanel();  pane3.add(new Label(str3));        pane3.add(text_sum);        JPanel pane4=new JPanel();  pane4.add(new Label(str4));        pane4.add(btnresult);        JPanel pane5=new JPanel();        pane5.add(btnshow);                 a.add(pane1);        a.add(pane2);        a.add(pane3);        a.add(pane4);        a.add(pane5);    }          public static void main(String[] args){        JFrame.setDefaultLookAndFeelDecorated(true);        FirstSwingApplication frame=new FirstSwingApplication();        frame.setVisible(true);     }}

Answer 2

 JTextField jtf = new JTextField("默认值");