【Java】实现一个根据日期判断星座程序的编写

思路

直接根据月份做索引，然后根据日期边界判断是本月的星座还是上月的。

算法

    private static String getAstro(int month, int day) {
    	String[] starArr = {"魔羯座","水瓶座", "双鱼座", "牡羊座",
    		"金牛座", "双子座", "巨蟹座", "狮子座", "处女座", "天秤座", "天蝎座", "射手座" };
    	int[] DayArr = {22, 20, 19, 21, 21, 21, 22, 23, 23, 23, 23, 22};  // 两个星座分割日
        int index = month;
        // 所查询日期在分割日之前，索引-1，否则不变
        if (day < DayArr[month - 1]) {
                index = index - 1;
        }
        // 返回索引指向的星座string
        return starArr[index];
    }

最终的效果图

初始图：

选择图：

判断星座

Java代码

package com.test0803;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
/*
 *
 * */
class MyFrameee extends JFrame implements ItemListener {

	private JComboBox day = new JComboBox(), month = new JComboBox();
	private JLabel tip = new JLabel("请选择日期");
	public static final String[] starArr = {"魔羯座","水瓶座", "双鱼座", "牡羊座",
		"金牛座", "双子座", "巨蟹座", "狮子座", "处女座", "天秤座", "天蝎座", "射手座" };
	public static final int[] DayArr = {22, 20, 19, 21, 21, 21, 22, 23, 23, 23, 23, 22};   

	MyFrameee() {
		super("星座计算");
		for (int i = 1; i <= 12; i++) {
			//void addItem(Object anObject)  为项列表添加项。
			month.addItem(String.valueOf(i));
		}
		for (int i = 1; i <= 31; i++) {
			day.addItem(String.valueOf(i));
		}
		//setForeground:设置此组件的前景色。
		tip.setForeground(Color.blue);

		Container con = getContentPane();
		con.setLayout(new FlowLayout());
		con.add(month);
		con.add(new JLabel("月-"));
		con.add(day);
		con.add(new JLabel("日"));
		con.add(tip);
		day.addItemListener(this);
		month.addItemListener(this);
		setSize(280, 100);
		setLocation(400, 300);
		setVisible(true);
		setResizable(false);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}

	public static String getConstellation(Calendar time) {
	    int month = time.get(Calendar.MONTH);
	    int day = time.get(Calendar.DAY_OF_MONTH);
	    if (day < DayArr[month]) {
	        month = month - 1;
	    }
	    if (month >= 0) {
	        return starArr[month];
	    }
	    return starArr[0];
	}  

	public void itemStateChanged(ItemEvent e) {
		Calendar date = Calendar.getInstance();
		date.set(2010, Integer.parseInt((String) month.getSelectedItem()),
				Integer.parseInt((String) day.getSelectedItem()));
		tip.setText(getConstellation(date));
	}
}

public class Test_Star2 {
	public static void main(String[] args) {
		new MyFrameee();
	}
}

不足之处

为了方便，没有确定特殊月份的日期数量，都是按照31天处理的。