1 package test;
 2 public class Triangle {
 3     public String triangle(int a,int b,int c){
 4         String str=null;
 5         if(a+b>c){
 6             if((a == b)||(b == c)&&(a!=c))
 7             {
 8                 str = "等腰三角形";
 9             }
10             else if(a == b&& b== c)
11             {
12                 str = "等边三角形";
13             }else if(a*a+b*b==c*c){
14                 str = "直角三角形";
15             }else
16                 str="一般三角形";
17             }
18             else {
19                 str = "不构成三角形";
20             }
21             return str;
22     }
23     public float triangleArea(int a,int b,int c){
24         float p=(a+b+c)/2;
25         float s=(float)Math.sqrt(p*(p-a)*(p-b)*(p-c));
26         return s;
27     }
28     public  int Perimeter(int a,int b,int c){
29         return a+b+c;
30     }
31 }

  1 package test;
  2
  3 import java.awt.EventQueue;
  4 import java.awt.event.ActionEvent;
  5 import java.awt.event.ActionListener;
  6 import javax.swing.JFrame;
  7 import javax.swing.JLabel;
  8 import javax.swing.JOptionPane;
  9 import javax.swing.JTextField;
 10 import javax.swing.JButton;
 11 import java.awt.event.WindowEvent;
 12 import java.util.Arrays;
 13 import java.awt.event.WindowAdapter;
 14
 15 public class FrameTriangle {
 16     private JFrame frame = new JFrame("三角形计算程序");
 17     private JButton b1 = new JButton("OK");
 18     private JButton b2 = new JButton("Cancel");
 19     private JLabel lab1 = new JLabel("请输入三角形的三条边：");
 20     private JLabel length1 = new JLabel("a:");
 21     private JLabel length2 = new JLabel("b:");
 22     private JLabel length3 = new JLabel("c:");
 23     private JLabel define = new JLabel("这个三角形是：");
 24     private JLabel area = new JLabel("面积是:");
 25     private JLabel perimeter = new JLabel("周长是:");
 26     private JTextField a = new JTextField();
 27     private JTextField b = new JTextField();
 28     private JTextField c = new JTextField();
 29     private JTextField judge = new JTextField();
 30     private JTextField s = new JTextField();
 31     private JTextField per = new JTextField();
 32     Triangle t=new Triangle();
 33     public FrameTriangle(){
 34         b1.addActionListener(new ActionListener(){
 35         @Override
 36             public void actionPerformed(ActionEvent e){
 37                 try{
 38                     int[] num;
 39                     num = new int[3];
 40                     num[0]=Integer.parseInt(a.getText());
 41                     num[1]=Integer.parseInt(b.getText());
 42                     num[2]=Integer.parseInt(c.getText());
 43                     if(num[0]>100||num[0]<1||num[1]>100||num[1]<1||num[2]>100||num[2]<1){
 44                         JOptionPane.showMessageDialog(null,"边的值不在范围内");
 45                         return;
 46                     }
 47                     Arrays.sort(num);
 48                     judge.setText(t.triangle(num[0],num[1],num[2]));
 49                     s.setText(""+t.triangleArea(num[0],num[1],num[2]));
 50                     per.setText(""+t.Perimeter(num[0],num[1],num[2]));
 51                 }catch(Exception ex){
 52                     JOptionPane.showMessageDialog(null,"请输入整数");
 53                  }
 54            }
 55        });
 56        b2.addActionListener(new ActionListener(){
 57            @Override
 58            public void actionPerformed(ActionEvent e) {
 59            a.setText("");
 60            b.setText("");
 61            c.setText("");
 62            judge.setText("");
 63            s.setText("");
 64            per.setText("");
 65        }});
 66        frame.addWindowListener(new WindowAdapter(){
 67            public void windowClosing(WindowEvent e){
 68                System.exit(1);
 69            }
 70        });
 71        frame.setLayout(null);
 72        lab1.setBounds(55,10,350,30);
 73        length1.setBounds(55,60,30,15);
 74        length2.setBounds(145,60,30,15);
 75        length3.setBounds(225,60,30,15);
 76        define.setBounds(55,130,300,30);
 77        area.setBounds(55,180,50,20);
 78        perimeter.setBounds(180,180,50,20);
 79        a.setBounds(70,55,50,25);
 80        b.setBounds(160,55,50,25);
 81        c.setBounds(240,55,50,25);
 82        judge.setBounds(140,130,150,30);
 83        s.setBounds(100,180,55,25);
 84        per.setBounds(230,180,55,25);
 85        b1.setBounds(55,90,100,30);
 86        b2.setBounds(175,90,100,30);
 87        frame.add(lab1);
 88        frame.add(length1);
 89        frame.add(length2);
 90        frame.add(length3);
 91        frame.add(define);
 92        frame.add(area);
 93        frame.add(perimeter);
 94        frame.add(a);
 95        frame.add(b);
 96        frame.add(c);
 97        frame.add(judge);
 98        frame.add(s);
 99        frame.add(per);
100        frame.add(b1);
101        frame.add(b2);
102        frame.setSize(500,400);
103        frame.setVisible(true);
104     }
105     public static void main(String[] args){
106         EventQueue.invokeLater(new Runnable() {
107             public void run() {
108                 try{
109                     FrameTriangle window = new FrameTriangle();
110                     window.frame.setVisible(true);
111                     }catch (Exception e){
112                         e.printStackTrace();
113                      }
114             }
115         });
116     }
117 }