java文件

com.java

@@ -0,0 +1,118 @@
+package computer;
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.text.MessageFormat;
+import java.util.Arrays;
+public class com {
+    public static void main(String[] args) {
+        new JS();
+    }
+}
+class JS extends JFrame implements ActionListener {
+    private final StringBuilder sBuilder = new StringBuilder();
+    JTextArea text = new JTextArea();
+    double a, b;
+    Double sum;
+    String lastOperator = "=";
+    public JS() {
+        setBounds(100, 100, 400, 400);
+        setTitle("计算器");
+        JMenuBar menubar = new JMenuBar();
+        this.setJMenuBar(menubar);
+        this.setLayout(new BorderLayout());
+        JPanel p1 = new JPanel();
+        JPanel p2 = new JPanel();
+        text.setPreferredSize(new Dimension(370, 60));
+        p2.setLayout(new FlowLayout());
+        p1.add(text);
+        this.add(p1, BorderLayout.NORTH);
+        p2.setLayout(new GridLayout(5, 4));
+        JButton[] button = new JButton[20];
+        button[0] = new JButton("C");
+        button[1] = new JButton("CE");
+        button[2] = new JButton("%");
+        button[3] = new JButton("÷");
+        button[4] = new JButton("7");
+        button[5] = new JButton("8");
+        button[6] = new JButton("9");
+        button[7] = new JButton("*");
+        button[8] = new JButton("4");
+        button[9] = new JButton("5");
+        button[10] = new JButton("6");
+        button[11] = new JButton("-");
+        button[12] = new JButton("1");
+        button[13] = new JButton("2");
+        button[14] = new JButton("3");
+        button[15] = new JButton("+");
+        button[16] = new JButton(" ");
+        button[17] = new JButton("0");
+        button[18] = new JButton(".");
+        button[19] = new JButton("=");
+        Arrays.stream(button).forEach(p2::add);
+        this.add(p2, BorderLayout.CENTER);
+        for (JButton jButton : button) {
+            jButton.addActionListener(this);
+        }
+        this.setVisible(true);
+        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+    }
+    public void actionPerformed(ActionEvent e) {
+        String lab = e.getActionCommand();
+
+        if (Character.isDigit(lab.charAt(0)) || lab.equals(".")) {
+            sBuilder.append(lab);
+            text.setText(sBuilder.toString());
+        } else if (lab.equals("CE")) {
+            sBuilder.deleteCharAt(sBuilder.length() - 1);
+            text.setText(sBuilder.toString());
+        } else if (lab.equals("C")) {
+            sBuilder.setLength(0);
+            text.setText("");
+        } else if (lab.equals("+") || lab.equals("-") || lab.equals("*") || lab.equals("÷") || lab.equals("%")) {
+            if (sBuilder.length() > 0) {
+                a = Double.parseDouble(sBuilder.toString());
+                sBuilder.setLength(0);
+                lastOperator = lab;
+                text.setText(MessageFormat.format("{0} {1} ", a, lastOperator));
+            }
+        } else if (lab.equals("=")) {
+            if (lastOperator != null && !lastOperator.isEmpty() && sBuilder.length() > 0) {
+                b = Double.parseDouble(sBuilder.toString());
+                calculate();
+            }
+        }
+    }
+    private void calculate() {
+        switch (lastOperator) {
+            case "+":
+                sum = a + b;
+                break;
+            case "-":
+                sum = a - b;
+                break;
+            case "*":
+                sum = a * b;
+                break;
+            case "÷":
+                if (b == 0) {
+                    text.setText("除数不能为0");
+                    return;
+                }
+                sum = a / b;
+                break;
+            case "%":
+                if (b == 0) {
+                    text.setText("除数不能为0");
+                    return;
+                }
+                sum = a % b;
+                break;
+        }
+        text.setText(sum + "");
+        sBuilder.setLength(0);
+        sBuilder.append(sum);
+        lastOperator = "=";
+    }
+}