常用类Calendar的练习。。。 - 黑马程序员技术交流社区

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Calendar;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
/**
* 从键盘输入一个年份，将这一年中所有周日是几号显示出来。
周日是几号如何显示求学长分析。谢谢！
*/
class WeekOfYear extends JFrame {
//创建成员变量
private JTextField filed = new JTextField(25);
private JTextArea txt = new JTextArea(5,25);
private JButton button = new JButton("显示");
private JButton clear = new JButton("清除");
private Calendar calendar=Calendar.getInstance();
public WeekOfYear(){
init();
}
//初始化窗体和组件
private void init() {
setLayout(new FlowLayout());
setResizable(false);
setLocation(300,100);
add(filed);
add(new JScrollPane(txt));
add(button);
add(clear);
event();
}
public void event(){
button.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
String str=filed.getText().trim();
if((str.matches("\\D+"))){
JOptionPane.showMessageDialog(null, "请输入中文年份!");
filed.setText("");
return ;
}
int count=1;
int month,day;
for(int i=0;i<7;i++){
calendar.set(Integer.parseInt(str), 0,i);
if(calendar.get(Calendar.DAY_OF_WEEK)==1)
break;
}
txt.append("月份:"+(calendar.get(Calendar.MONTH)+1)+" 本月第:"
+calendar.get(Calendar.DAY_OF_MONTH)+"天\n");
while(calendar.get(Calendar.WEEK_OF_YEAR)!=1){
calendar.add(Calendar.DAY_OF_YEAR, +7);
month=calendar.get(Calendar.MONTH)+1;
day=calendar.get(Calendar.DAY_OF_MONTH);
txt.append("月份:"+month+" 本月第:"+day+"日\n");
count++;
}
txt.append("本月度一共:"+count+"周!");
}
});
clear.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
txt.setText("");
}
});
}
public static void main(String[] args) {
SwingConsole.run(new WeekOfYear(), 300, 200);
}
}
public class SwingConsole extends JFrame {
public static void run(final JFrame frame,final int width,final int height){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
frame.setVisible(true);
frame.setSize(width,height);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
});
}
}

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