SWUST--Java三角形面积计算

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.border.TitledBorder;

public class homework5 extends JFrame {
	JPanel jp = new JPanel();
	JLabel jb[] = new JLabel[3];
	JTextField jf[] = new JTextField[3];
	String names[] = { "三角形1边:", "三角形2边:", "三角形3边:" };
	JButton jt = new JButton("点我");

	public homework5() {
		TitledBorder borderFactory = BorderFactory.createTitledBorder("我是边框0.0");
		borderFactory.setTitleJustification(TitledBorder.RIGHT);
		jp.setBorder(borderFactory);
		setTitle("三角形周长");
		setBounds(200, 100, 240, 180);

		for (int i = 0; i < jb.length; i++) {
			jb[i] = new JLabel(names[i]);
			jf[i] = new JTextField();
			jf[i].setColumns(8);
			jp.add(jb[i]);
			jp.add(jf[i]);
		}

		JLabel jb1 = new JLabel("三角形C:");
		JLabel jb2 = new JLabel(" ");

		jt.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent arg0) {
				String x1 = jf[0].getText();
				String x2 = jf[0].getText();
				String x3 = jf[0].getText();

				test_5 dx = new test_5(x1, x2, x3);

				if (dx.juge() == true) {
					int s1 = Integer.parseInt(jf[0].getText());
					int s2 = Integer.parseInt(jf[1].getText());
					int s3 = Integer.parseInt(jf[2].getText());

					if ((s1 + s2 > s3) && (s1 + s3 > s2) && (s2 + s3 > s1)) {
						int i = s1 + s2 + s3;
						jb2.setText(i + "");
					} else {
						jb2.setText("我算不出来555");
					}
				} else {
					jb2.setText("error!");
				}
			}
		});

		jp.add(jt);
		jp.add(jb1);
		jp.add(jb2);
		add(jp);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
	}

	public static void main(String[] args) {
		new homework5();
	}
}

public class test_5 {
	String s1, s2, s3;

	public test_5(String s1, String s2, String s3) {
		this.s1 = s1;
		this.s2 = s2;
		this.s3 = s3;
	}

	boolean juge() {
		int flag = 0;
		for (int i = 0; i < s1.length(); i++) {
			if (s1.charAt(i) >= 'a' && s1.charAt(i) <= 'z')
				flag = 1;
		}
		for (int i = 0; i < s2.length(); i++) {
			if (s2.charAt(i) >= 'a' && s2.charAt(i) <= 'z')
				flag = 1;
		}
		for (int i = 0; i < s3.length(); i++) {
			if (s3.charAt(i) >= 'a' && s3.charAt(i) <= 'z')
				flag = 1;
		}
		if (flag == 0)
			return true;
		else
			return false;
	}
}