diff --git a/src/java2020spring/Calculator.java b/src/java2020spring/Calculator.java
new file mode 100644
index 0000000000000000000000000000000000000000..0f38ad59214a4fa91591eee200451addd9f077e1
--- /dev/null
+++ b/src/java2020spring/Calculator.java
@@ -0,0 +1,627 @@
+package java2020spring;
+
+import java.awt.*;
+import javax.swing.*;
+import java.awt.event.*;
+import java.util.LinkedList;
+import java.util.Scanner;
+
+public class Calculator extends JFrame implements ActionListener {
+	public static JTextField showText1, showText2; // 1为显示框，2为输入框
+	public static JPanel mainp = new JPanel(); // mainp为主面板
+	public static JPanel p = new JPanel(); // 放按钮的面板
+	public static JPanel p0 = new JPanel(); // 放文本框的面板
+	public static JMenuBar menubar;
+	public static JMenu menu, subMenu1, subMenu2, menu2, menu3;
+	public static String str1 = "", str2 = "";
+	double result, m, n, flag = 0; // flag指示变量，判断按"="前按的是哪个按键
+	public static String[] anniu = { "e^x", "π", "e", "C", "DEL",
+
+			"X^2", "1/x", "|x|", "exp", "mod",
+
+			"√x", "(", ")", "n!", "÷",
+
+			"x^y", "7", "8", "9", "x",
+
+			"10^x", "4", "5", "6", "-",
+
+			"lg", "1", "2", "3", "+",
+
+			"ln", "+/-", "0", ".", "=" };
+	public static String[] sanjiao = { "sin", "cos", "tan", "sec", "csc", "cot" };
+	public static String[] fansanjiao = { "sin^-1", "cos^-1", "tan^-1", "根据角度求弧度" };
+	public static String[] gengduo = { "x^3", "3√x", "y√x", "2^x", "logyx" };
+	public JButton button[] = new JButton[anniu.length];
+	public JButton sanjiao1[] = new JButton[sanjiao.length];
+	public JButton fansanjiao1[] = new JButton[fansanjiao.length];
+	public JButton qita[] = new JButton[gengduo.length];
+
+	public Calculator() {
+		init();
+	}
+
+	// 版面设计
+	void init() {
+		mainp.setLayout(new BorderLayout());
+		menubar = new JMenuBar();
+		menu = new JMenu("三角学");
+		menu2 = new JMenu("更多");
+		menu3 = new JMenu("计算时间");
+		subMenu1 = new JMenu("1nd");
+		subMenu2 = new JMenu("2nd");
+		menu.add(subMenu1);
+		menu.addSeparator();
+		menu.add(subMenu2);
+		// 为子菜单添加按钮
+		/* 子菜单1计算三角函数 */
+		JPanel p1 = new JPanel();
+		for (int i = 0; i < 6; i++) {
+			sanjiao1[i] = new JButton(sanjiao[i]);
+			p1.add(sanjiao1[i]);
+		}
+		/* 子菜单2计算反三角函数 */
+		JPanel p2 = new JPanel();
+		for (int i = 0; i < 4; i++) {
+			fansanjiao1[i] = new JButton(fansanjiao[i]);
+			p2.add(fansanjiao1[i]);
+		}
+		/* 菜单“更多” */
+		JPanel p3 = new JPanel();
+		for (int i = 0; i < 5; i++) {
+			qita[i] = new JButton(gengduo[i]);
+			p3.add(qita[i]);
+		}
+		JPanel p4 = new JPanel();
+		JButton huan = new JButton("另一界面");
+		p4.add(huan);//
+		subMenu1.add(p1);
+		subMenu2.add(p2);
+		menu2.add(p3);
+		menu3.add(p4);
+		menubar.add(menu);
+		menubar.add(menu2);
+		menubar.add(menu3);
+
+		this.setJMenuBar(menubar);// 添加计算三角学、更多函数的功能
+
+		showText1 = new JTextField(30);
+		showText2 = new JTextField(30);
+		showText1.setFont(new java.awt.Font("黑体", Font.PLAIN, 40));
+		showText2.setFont(new java.awt.Font("黑体", Font.PLAIN, 40));
+		this.setBackground(Color.cyan);
+		setLayout(new BorderLayout());
+		p.setLayout(new GridLayout(7, 5));
+		p0.setLayout(new BorderLayout());
+		p0.add(showText1, BorderLayout.NORTH);
+
+		p0.add(showText2, BorderLayout.CENTER);
+		mainp.add(p0, BorderLayout.NORTH);
+		mainp.add(p, BorderLayout.CENTER);
+		showText1.setPreferredSize(new Dimension(420, 50));
+		showText2.setPreferredSize(new Dimension(420, 70));
+		showText1.setEnabled(false);
+		for (int i = 0; i < anniu.length; i++) {
+
+			button[i] = new JButton(anniu[i]);
+			button[i].setPreferredSize(new Dimension(10, 10));
+			button[i].setFont(new Font("黑体", 1, 20));
+			p.add(button[i]);
+		}
+
+		for (int i = 0; i < anniu.length; i++) {
+			if (i == 16 || i == 17 || i == 18 || i == 21 || i == 22 || i == 23 || i == 26 || i == 27 || i == 28
+					|| i == 31 || i == 32 || i == 33) {
+				button[i].setBackground(Color.white);
+			} else {
+
+				button[i].setBackground(Color.lightGray);
+
+			}
+		}
+
+		showText1.setHorizontalAlignment(SwingConstants.RIGHT);
+		showText2.setHorizontalAlignment(SwingConstants.RIGHT);
+		add(mainp);
+
+		// 注册监听器
+
+		huan.addActionListener(this);
+		for (int i = 0; i < button.length; i++) { // 每个按钮都注册监听器
+			button[i].addActionListener(this);
+		}
+		for (int i = 0; i < sanjiao1.length; i++) {
+			sanjiao1[i].addActionListener(this);
+		}
+		for (int i = 0; i < fansanjiao1.length; i++) {
+			fansanjiao1[i].addActionListener(this);
+		}
+		for (int i = 0; i < qita.length; i++) {
+			qita[i].addActionListener(this);
+		}
+
+	}
+
+	@Override
+	public void actionPerformed(ActionEvent e) {
+
+		// 实现相关功能
+		// 什么都没有输入的情况下点击按钮，报错提示重新输入
+		if (str2 == "") {
+			try {
+				throw new java.lang.NumberFormatException();
+			}
+
+			catch (java.lang.NumberFormatException ee) {
+				showText1.setText("无效输入!请重新输入！");
+			}
+		}
+		// 按下菜单中按钮转换界面计算时间
+		if (e.getActionCommand() == "另一界面") {
+			mainp.removeAll();
+			mainp.add(new PanelNullLayout());
+			mainp.validate();
+			mainp.repaint();
+
+		}
+
+		// 按下1-9
+		if (e.getSource() == button[16] || e.getSource() == button[17] || e.getSource() == button[18]
+				|| e.getSource() == button[21] || e.getSource() == button[22] || e.getSource() == button[23]
+				|| e.getSource() == button[26] || e.getSource() == button[27] || e.getSource() == button[28]) {
+			str2 = str2 + e.getActionCommand();
+			showText2.setText(str2);
+			showText1.setText(str2);
+		}
+		// 按下0
+		if (e.getActionCommand().equals("0")) {
+			str2 += e.getActionCommand();
+			showText2.setText(str2);
+			showText1.setText(str2);
+		}
+
+		// 按下小数点
+
+		if (e.getActionCommand().equals(".")) {
+
+			str2 += ".";
+			showText2.setText(str2);
+			showText1.setText(str2);
+		}
+
+		// 按下 "("
+		if (e.getActionCommand().equals("(")) {
+			str2 += "(";
+			showText2.setText(str2);
+			showText1.setText("抱歉，尚不可用");
+		}
+		// 按下")"
+		if (e.getActionCommand().equals(")")) {
+			str2 += ")";
+			showText2.setText(str2);
+			showText1.setText("抱歉，尚不可用");
+		}
+		// 按下DEL退一格
+		if (e.getActionCommand().equals("DEL")) {
+			if (str2.length() == 0 && str2.length() == 1) {
+				str2 = "";
+			} else {
+				StringBuffer s = new StringBuffer(showText2.getText());
+				s.deleteCharAt(showText2.getText().length() - 1);
+				showText2.setText(s.toString());
+				str1 = showText2.getText();
+				showText1.setText(str1);
+				str2 = s.toString();
+			}
+		}
+		// 按下C按钮清除
+		if (e.getActionCommand().equals("C")) {
+			str1 = "";
+			str2 = "";
+			showText1.setText(str1);
+			showText2.setText(str2);
+		}
+
+		// 按下加减乘除
+		if (e.getActionCommand().equals("+") || e.getActionCommand().equals("-") || e.getActionCommand().equals("x")
+				|| e.getActionCommand().equals("÷")) {
+			str2 = str2 + e.getActionCommand();
+			showText2.setText(str2);
+
+		}
+		// "x^y"
+		if (e.getActionCommand().equals("x^y")) {
+			str1 = str2;
+			str2 = "";
+			flag = 1;
+
+		}
+
+		if (e.getActionCommand().equals("=") && flag == 1) {
+			m = Double.parseDouble(str2);
+			n = Double.parseDouble(str1);
+			result = Math.pow(n, m);
+			showText2.setText(result + "");
+			showText1.setText(n + "^" + m + "=");
+			flag = 0;
+		}
+		// "exp"科学计数
+		if (e.getActionCommand().equals("exp")) {
+			str1 = str2;
+			str2 = "";
+			flag = 2;
+		}
+		if (e.getActionCommand().equals("=") && flag == 2) {
+			m = Double.parseDouble(str2);
+			n = Double.parseDouble(str1);
+			result = Math.pow(10, m) * n;
+			showText2.setText(result + "");
+			flag = 0;
+		}
+		// "mod"求余
+		if (e.getActionCommand().equals("mod")) {
+			str1 = str2;
+			str2 = "";
+			flag = 3;
+		}
+		if (e.getActionCommand().equals("=") && flag == 3) {
+			n = Double.parseDouble(str2);
+			m = Double.parseDouble(str1);
+			result = m % n;
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText(str1 + "mod" + str2 + "=");
+			flag = 0;
+		}
+
+		// "√x"开根号
+		if (e.getActionCommand().equals("√x")) {
+			m = Double.parseDouble(str2);
+			if (m >= 0) {
+				result = Math.sqrt(m);
+				str2 = "" + result;
+				showText2.setText(str2);
+				showText1.setText("√" + m + "=");
+
+			} else {
+				showText1.setText("数值大于零，才能开根号");
+			}
+		}
+		// "X^2" 平方
+		if (e.getActionCommand().equals("X^2")) {
+			m = Double.parseDouble(str2);
+			result = m * m;
+			str2 = "" + result;
+			showText2.setText(str2);
+			showText1.setText(m + "^2" + "=");
+		}
+		// "1/x"倒数
+		if (e.getActionCommand().equals("1/x")) {
+			if (str2 == "0") {
+				showText1.setText("除数不能为0!");
+			} else if (Double.parseDouble(str2) != 0) {
+				m = Double.parseDouble(str2);
+				result = 1 / m;
+				str2 = "" + result;
+				showText2.setText(str2);
+				showText1.setText("1/" + m + "=");
+
+			} else {
+				showText1.setText("除数不能为0!");
+			}
+		}
+		// 求e^x
+		if (e.getActionCommand().equals("e^x")) {
+			m = Double.parseDouble(str2);
+			result = Math.pow(2.718281828459, m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("e^" + m + "=");
+		}
+
+		// "+/-"号
+		if (e.getActionCommand().equals("+/-")) {
+			str2 = "-" + str2;
+			showText2.setText(str2);
+			showText1.setText(str2);
+
+		}
+		// "π"
+		if (e.getActionCommand().equals("π")) {
+			str2 += "3.1415926535898";
+			showText2.setText(str2);
+			showText1.setText(str2);
+		}
+		// "e"
+		if (e.getActionCommand().equals("e")) {
+			str2 += "2.718281828459";
+			showText2.setText(str2);
+			showText1.setText(str2);
+		}
+		// "|x|"
+		if (e.getActionCommand().equals("|x|")) {
+			m = Double.parseDouble(str2);
+			result = Math.abs(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("|" + m + "|" + "=");
+		}
+		// "n!"
+		if (e.getActionCommand().equals("n!")) {
+			m = Double.parseDouble(str2);
+			if (m % 1 != 0) {
+				showText1.setText("error!请输入整数");
+			} else if (m >= 0) { // 0的阶乘为1
+				result = 1;
+				for (int i = 1; i <= m; i++) {
+					result = result * i;
+				}
+
+				str2 = result + "";
+				showText2.setText(str2);
+				showText1.setText("fact" + "(" + m + ")" + "=");
+			}
+		}
+
+		// "10^x"
+		if (e.getActionCommand().equals("10^x")) {
+			m = Double.parseDouble(str2);
+			result = Math.pow(10, m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("10^" + m + "=");
+		}
+		// "lg"
+		if (e.getActionCommand().equals("lg")) {
+			m = Double.parseDouble(str2);
+			if (m > 0) {
+				result = Math.log10(m);
+				str2 = result + "";
+				showText2.setText(str2);
+				showText1.setText("lg" + m + "=");
+			} else {
+				showText1.setText("请输入大于0的数!");
+			}
+		}
+		// "ln"
+		if (e.getActionCommand().equals("ln")) {
+			m = Double.parseDouble(str2);
+			if (m > 0) {
+				result = Math.log(m);
+				str2 = "" + Integer.parseInt(new java.text.DecimalFormat("0").format(result)); // 四舍五入
+				showText2.setText(str2);
+				showText1.setText("ln" + m + "=");
+			} else {
+				showText1.setText("请输入大于0的数!");
+			}
+
+		}
+		// 菜单“更多”里的函数
+		// "x^3"
+		if (e.getActionCommand().equals("x^3")) {
+			m = Double.parseDouble(str2);
+			result = m * m * m;
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText(m + "^3" + "=");
+		}
+		// "3√x"
+		if (e.getActionCommand().equals("3√x")) {
+			m = Double.parseDouble(str2);
+			result = Math.cbrt(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("3√" + m + "=");
+		}
+		// "y√x"
+		if (e.getActionCommand().equals("y√x")) {
+			str1 = str2;
+			str2 = "";
+			flag = 4;
+		}
+
+		if (e.getActionCommand().equals("=") && flag == 4) {
+			m = Double.parseDouble(str1);
+			n = Double.parseDouble(str2);
+			result = Math.pow(m, 1 / n);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText(n + "√" + m + "=");
+			flag = 0;
+		}
+		// "2^x"
+		if (e.getActionCommand().equals("2^x")) {
+			m = Double.parseDouble(str2);
+			result = Math.pow(2, m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("2^" + m + "=");
+		}
+		// "logyx"
+		if (e.getActionCommand().equals("logyx")) {
+			flag = 5;
+			str1 = str2;
+			str2 = "";
+		}
+		if (e.getActionCommand().equals("=") && flag == 5) {
+			m = Double.parseDouble(str1);
+			n = Double.parseDouble(str2);
+			if (n != 1 && m > 0 && n > 0) // 保证真数和分母都大于0
+			{
+				result = Math.log(m) / Math.log(n);
+				str2 = result + "";
+				showText2.setText(str2);
+				showText1.setText("log" + m + n + "=");
+				flag = 0;
+			} else {
+				showText1.setText("真数需都大于0，且分母不能为0");
+			}
+		}
+		// 三角学“1nd”的计算
+		if (e.getActionCommand().equals("sin")) {
+			m = Double.parseDouble(str2);
+			result = Math.sin(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("sin" + m + "=");
+		}
+		if (e.getActionCommand().equals("cos")) {
+			m = Double.parseDouble(str2);
+			result = Math.cos(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("cos" + m + "=");
+		}
+		if (e.getActionCommand().equals("tan")) {
+			m = Double.parseDouble(str2);
+			result = Math.tan(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("tan" + m + "=");
+		}
+		if (e.getActionCommand().equals("sec")) {
+			m = Double.parseDouble(str2);
+			result = 1 / Math.cos(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("sec" + m + "=");
+		}
+		if (e.getActionCommand().equals("csc")) {
+			m = Double.parseDouble(str2);
+			result = 1 / Math.cos(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("csc" + m + "=");
+		}
+		if (e.getActionCommand().equals("cot")) {
+			m = Double.parseDouble(str2);
+			result = 1 / Math.tan(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("cot" + m + "=");
+		}
+		// 三角学"2nd"即已知值求角度的计算
+		if (e.getActionCommand().equals("sin^-1")) {
+			m = Double.parseDouble(str2);
+			result = Math.asin(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("sin^-1" + "(" + m + ")");
+		}
+		if (e.getActionCommand().equals("cos^-1")) {
+			m = Double.parseDouble(str2);
+			result = Math.acos(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("cos^-1" + "(" + m + ")");
+		}
+		if (e.getActionCommand().equals("tan^-1")) {
+			m = Double.parseDouble(str2);
+			result = Math.atan(m);
+			str2 = result + "";
+			showText2.setText(str2);
+			showText1.setText("tan^-1" + "(" + m + ")");
+
+		}
+		if (e.getActionCommand().equals("根据角度求弧度")) {
+			m = Double.parseDouble(str2);
+			result = Math.toRadians(m);
+			str2 = result + "";
+			showText2.setText(str2);
+		}
+		// 按下"="
+		if (e.getActionCommand().equals("=")) {
+
+			showText1.setText(showText2.getText() + button[34].getText());
+			Scanner scanner = new Scanner(showText2.getText()); // 用Scanner分割输入框输入的字符，得到一个个字符
+			str2 = saveNumberAndCalculator(scanner.next()); // 分别存符号和数字直到没有字符
+			showText2.setText(str2);
+
+		}
+	}
+
+	// 分割字符串,把运算符和数字分别放到fuhaoList和numberList里
+	public String saveNumberAndCalculator(String str) {
+		// 若第一个数字是负数，在"-"前加0
+		if (str.startsWith("-")) {
+			StringBuffer s1 = new StringBuffer(str);
+			s1.insert(0, "0");
+			str = s1.toString();
+		}
+		// 加上"#"用于获取分割最后一个数字
+		str = str + "#";
+		char[] strChar = str.toCharArray();
+		LinkedList<String> fuhaoList = new LinkedList<>(); // 存储运算符号
+		LinkedList<String> numberList = new LinkedList<>(); // 存储数字
+		StringBuffer buffer = new StringBuffer();
+		for (char fuhao : strChar) {
+			if (fuhao == '+' || fuhao == '-' || fuhao == 'x' || fuhao == '÷') {
+				fuhaoList.add(String.valueOf(fuhao));
+				numberList.add(buffer.toString());
+				buffer.delete(0, buffer.length());
+			}
+			// 判断是不是最后一个数,是的话加到数字列表里
+			else if (fuhao == '#') {
+				numberList.add(buffer.toString());
+			} else {
+				buffer.append(fuhao);
+			}
+		}
+		return calculateOrder(fuhaoList, numberList);
+	}
+
+	// 控制加减乘除的运算优先级顺序
+	public String calculateOrder(LinkedList<String> calculate, LinkedList<String> number) {
+		if (calculate.size() > 0) {
+			int multiply = calculate.indexOf("x");
+			int except = calculate.indexOf("÷");
+
+			// 如果乘在前除在后或者有乘无除，则先算乘
+			if ((multiply != -1 && except != -1 && multiply < except)
+					|| (calculate.contains("x") && !calculate.contains("÷"))) {
+				calculateResult("x", calculate, number);
+			}
+			// 如果除在前乘在后或者有除无乘，则先算除
+			else if ((multiply != -1 && except != -1 && except < multiply)
+					|| (calculate.contains("÷") && !calculate.contains("x"))) {
+				calculateResult("÷", calculate, number);
+			}
+			// 如果无乘除只有加减，则按规定从左往右计算
+			else if (calculate.size() > 0) {
+				calculateResult(calculate.get(0), calculate, number);
+			}
+		}
+		return number.get(0); // 返回最终数链表中第一个位置的数据，即经过一次计算的结果
+	}
+
+	// 通过location找到运算符在calculate出现的位置,根据位置在number中找到对应符号前后的两个数进行计算
+	public String calculateResult(String location, LinkedList<String> calculate, LinkedList<String> number) {
+		int position = calculate.indexOf(location);
+		double a = Double.parseDouble(number.get(position));
+		double b = Double.parseDouble(number.get(position + 1));
+		String calculateNumber = "";
+		switch (location) {
+		case "+":
+			calculateNumber = String.valueOf(a + b);
+			break;
+		case "-":
+			calculateNumber = String.valueOf(a - b);
+			break;
+		case "x":
+			calculateNumber = String.valueOf(a * b);
+			break;
+		case "÷":
+			if (b == 0) {
+				showText1.setText("除数不能为0!");
+				break;
+			} else {
+				calculateNumber = String.valueOf(a / b);
+				break;
+			}
+		}
+		number.set(position, calculateNumber);// 两个数算完后把结果给前一个数
+		calculate.remove(position);// 在calculate集中每算完一个符号就删一个符号
+		number.remove(position + 1);// 在number集中两个数运算完后删除后面的数
+		return calculateOrder(calculate, number); // 一直算直到calculate集中没有符号为止
+	}
+
+}
diff --git a/src/java2020spring/PanelNullLayout.java b/src/java2020spring/PanelNullLayout.java
new file mode 100644
index 0000000000000000000000000000000000000000..36aaf5175743f4f07c5466b793e09a56d3f065c4
--- /dev/null
+++ b/src/java2020spring/PanelNullLayout.java
@@ -0,0 +1,106 @@
+package java2020spring;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.*;
+import java.util.*;
+
+public class PanelNullLayout extends JPanel implements ActionListener, ItemListener {
+	Calendar calendar;
+	static String year, month, day; // 所选起始时间
+	static int yearNow, monthNow, dayNow; // 现在时间
+	static long time1, time2;
+	JTextArea t1; // 显示区
+	JLabel a, b, c, d, e;
+	JComboBox choiceYear, choiceMonth, choiceDay;
+	JButton action;// 计算按钮
+
+	// 版面设计
+	PanelNullLayout() {
+		setLayout(null);
+		a = new JLabel("与今天相隔时间:");
+		b = new JLabel("起始时间：");
+		c = new JLabel("年");
+		d = new JLabel("月");
+		e = new JLabel("日");
+		t1 = new JTextArea(9, 30);
+		action = new JButton("计算");
+
+		calendar = Calendar.getInstance();
+		calendar.setTime(new Date());
+		yearNow = calendar.get(Calendar.YEAR);
+		monthNow = calendar.get(Calendar.MONTH) + 1;
+		dayNow = calendar.get(Calendar.DAY_OF_MONTH);
+		t1.setText("现在的时间是：" + yearNow + "年" + monthNow + "月" + dayNow + "日");
+		time1 = calendar.getTimeInMillis();
+		add(a);
+		add(b);
+		add(c);
+		add(d);
+		add(e);
+		add(t1);
+		add(action);
+
+		a.setBounds(40, 30, 120, 30);
+		b.setBounds(100, 50, 100, 40);
+		c.setBounds(230, 50, 20, 40);
+		d.setBounds(300, 50, 20, 40);
+		e.setBounds(370, 50, 20, 40);
+		t1.setBounds(100, 100, 200, 300);
+		action.setBounds(320, 100, 60, 40);
+
+		choiceYear = new JComboBox();
+		choiceMonth = new JComboBox();
+		choiceDay = new JComboBox();
+		choiceYear.addItem("0");
+		choiceMonth.addItem("0");
+		choiceDay.addItem("0");
+		for (int i = 1601; i <= 2601; i++) {
+			choiceYear.addItem(i);
+		}
+		for (int i = 1; i <= 12; i++) {
+			choiceMonth.addItem(i);
+		}
+		for (int i = 1; i <= 31; i++) {
+			choiceDay.addItem(i);
+		}
+		add(choiceYear);
+		add(choiceMonth);
+		add(choiceDay);
+		choiceYear.setBounds(160, 50, 60, 40);
+		choiceMonth.setBounds(250, 50, 40, 40);
+		choiceDay.setBounds(320, 50, 40, 40);
+
+		// 加监听器
+		choiceYear.addItemListener(this);
+		choiceMonth.addItemListener(this);
+		choiceDay.addItemListener(this);
+		action.addActionListener(this);
+
+	}
+
+	public void actionPerformed(ActionEvent e) {
+		try {
+			calendar.set(Integer.parseInt(year), Integer.parseInt(month) - 1, Integer.parseInt(day));
+			time2 = calendar.getTimeInMillis();
+			if (time1 >= time2) {
+				long subDay = (time1 - time2) / (1000 * 60 * 60 * 24);
+				t1.append("\n" + "与现在相隔" + subDay + "天");
+			} else {
+				long subDay = (time2 - time1) / (1000 * 60 * 60 * 24);
+				t1.append("\n" + "与现在相隔" + subDay + "天");
+			}
+
+		} catch (Exception exp) {
+			t1.append("\n错误！请选择起始时间!");
+		}
+
+	}
+
+	public void itemStateChanged(ItemEvent e) {
+		year = choiceYear.getSelectedItem().toString();
+		month = choiceMonth.getSelectedItem().toString();
+		day = choiceDay.getSelectedItem().toString();
+
+	}
+}
diff --git a/src/java2020spring/Test.java b/src/java2020spring/Test.java
index fc09c195f566d0e707f5e8a2f05fd168069c73a7..217cc4866003c25a4e977fb3ad4cbbe2ffdbab67 100644
--- a/src/java2020spring/Test.java
+++ b/src/java2020spring/Test.java
@@ -1,10 +1,16 @@
 package java2020spring;
 
+import javax.swing.JFrame;
+
 public class Test {
+	static Calculator win;
 
 	public static void main(String[] args) {
-		System.out.println("Hello world!");
-
+		win = new Calculator();
+		win.setTitle("ljl's calculator");
+		win.setBounds(100, 100, 450, 600);
+		win.setVisible(true);
+		win.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 	}
 
 }