//在“操作数”标签右侧的两个文本框中输入操作数，当单击“+，-，*，/”按钮时，对两个操作数进行运算并将结果填入到“结果”标签右侧的文本框中。
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Sjsq extends JFrame implements ActionListener{
    JLabel l1,l2,l3;
    JTextField text1,text2,text3;
    JButton b1,b2,b3,b4;
    JPanel p1,p2,p3,p4;
    public Sjsq() {
        setTitle("用户注册");
        setSize(399,230);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        l1=new JLabel("  操作数        ");
        l2=new JLabel("  操作数        ");
        l3=new JLabel("  结果            ");
        text1=new JTextField(15);
        text2=new JTextField(15);
        text3=new JTextField(15);
        b1=new JButton("+");
        b2=new JButton("-");
        b3=new JButton("*");
        b4=new JButton("/");
        b1.addActionListener(this);
        b2.addActionListener(this);
        b3.addActionListener(this);
        b4.addActionListener(this);
        p1=new JPanel();
        p2=new JPanel();
        p3=new JPanel();
        p4=new JPanel(new FlowLayout());
        p1.add(l1);
        p1.add(text1);
        p2.add(l2);
        p2.add(text2);
        p3.add(l3);
        p3.add(text3);
        p4.add(b1);
        p4.add(b2);
        p4.add(b3);
        p4.add(b4);
        Container con=getContentPane();
        con.setLayout(new FlowLayout());
        con.add(p1);
        con.add(p2);
        con.add(p4);
        con.add(p3);
        }
    public void actionPerformed(ActionEvent e){//这段的作用是将两个数相加，但此时的“+”起到的是连接作用！！！
        String sum;
        if(e.getSource()==b1){
            sum=text1.getText()+text2.getText();
            text3.setText(sum);
        }
    }
    public static void main(String[] args){
        new Sjsq();
    }

}

String idtext1=text1.getText().trim();
int aa=Integer.parseInt(idtext1);

text2.getText()也一样转换过来就可以了。

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#48，#65楼