java 下拉框级联及相关（转）

import java.awt.Dimension;
import java.awt.Font;
import java.awt.Rectangle;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.JComboBox;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class YearMonthDay extends JPanel {

 private int year;
 private int month;
 private int day;
 private final int STARTYEAR = 2000;// 年份的开始值
 private final int ENDYEAR = 2020;// 年份的结束值
 JPanel contentPane;
 // 年月日的选择框
 JComboBox cboYear = new JComboBox();
 JComboBox cboMonth = new JComboBox();
 JComboBox cboDay = new JComboBox();
 // 年月日标签
 JLabel jLabel1 = new JLabel();
 JLabel jLabel2 = new JLabel();
 JLabel jLabel3 = new JLabel();
 public YearMonthDay() {
  jbInit();
 }
 private void jbInit() {
  this.setLayout(null);
  setSize(new Dimension(200, 80));
  // 年的下拉选择框
  cboYear.setFont(new java.awt.Font("Dialog", Font.BOLD, 13));
  cboYear.setBounds(new Rectangle(0, 0, 55, 18));
  // cboYear.addItemListener(new DateItemAdapter(this));
  // 月的下拉选择框
  cboMonth.setFont(new java.awt.Font("Dialog", Font.BOLD, 13));
  cboMonth.setBounds(new Rectangle(80, 0, 45, 18));
  cboMonth.addItemListener(new DateItemAdapter(this));
  // 日的下拉选择框
  cboDay.setFont(new java.awt.Font("Dialog", Font.BOLD, 13));
  cboDay.setBounds(new Rectangle(150, 0, 45, 18));
  // cboDay.setEditable(true);
  // 年的label
  jLabel3.setFont(new java.awt.Font("Dialog", Font.BOLD, 15));
  jLabel3.setText("年");
  jLabel3.setBounds(new Rectangle(60, 0, 20, 20));
  // 月的label
  jLabel2.setFont(new java.awt.Font("Dialog", Font.BOLD, 15));
  jLabel2.setText("月");
  jLabel2.setBounds(new Rectangle(130, 0, 20, 20));
  // 日的label
  jLabel1.setFont(new java.awt.Font("Dialog", Font.BOLD, 15));
  jLabel1.setText("日");
  jLabel1.setBounds(new Rectangle(200, 0, 20, 20));
  this.add(cboYear);
  this.add(cboMonth);
  this.add(cboDay);
  this.add(jLabel3);
  this.add(jLabel2);
  this.add(jLabel1);
  // 添加初始值
  AddInfo();
  //设置默认的时间
  setYear(Integer.valueOf(cboYear.getSelectedItem().toString().trim()));
  setMonth(Integer.valueOf(cboMonth.getSelectedItem().toString().trim()));
  setDay(Integer.valueOf(cboDay.getSelectedItem().toString().trim()));
  
 }
 
 private void AddInfo() {
  // 年下拉选择框
  for (int i = STARTYEAR; i < ENDYEAR; i++) {
   cboYear.addItem("" + i);
  }
  //年的默认时间是2009年
  cboYear.setSelectedIndex(9);
  // 月下拉选择框
  for (int i = 0; i < 12; i++) {
   cboMonth.addItem("" + (i + 1));
  }
  // 日下拉选择框
  for (int j = 0; j < 31; j++) {
   cboDay.addItem("" + (j + 1));
  }
 }
 private int getYear() {
  return year;
 }
 private void setYear(int year) {
  this.year = year;
 }
 private int getMonth() {
  return month;
 }
 private void setMonth(int month) {
  this.month = month;
 }
 private int getDay() {
  return day;
 }
 private void setDay(int day) {
  this.day = day;
 }
 public String getDate(){
  return year+"-"+month+"-"+day;
 }
 @Override
 public String toString() {
  return this.getDate();
 }
 public void cboMonth_itemStateChanged(ItemEvent e) {
  Object yearObject = cboYear.getSelectedItem();
  Object monthObject = cboMonth.getSelectedItem();
  Object dayObject = cboDay.getSelectedItem();
  if (yearObject != null && monthObject != null && dayObject != null) {
   this.setYear(Integer.valueOf(yearObject.toString().trim()));
   int month = Integer.valueOf(cboMonth.getSelectedItem().toString());// 取得选
中月份
   this.setDay(Integer.valueOf(cboDay.getSelectedItem().toString()
     .trim()));
   cboDay.removeAllItems();// 清空日的下拉列表框
   int days = 31;
   if (month == 4 || month == 6 || month == 9 || month == 11) {
    days = 30;
   } else if (month == 2) {
    // 取得选中年份
    int year = Integer.parseInt(cboYear.getSelectedItem()
      .toString());
    if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) {
     // 是闰年
     days = 29;
    } else {
     // 不是闰年
     days = 28;
    }
   }// if
   for (int j = 0; j < days; j++) {
    cboDay.addItem("" + (j + 1));
   }// for
  }// if
 }
}// end class
// 事件监听器
class DateItemAdapter implements ItemListener {
 private YearMonthDay adaptee;
 DateItemAdapter(YearMonthDay adaptee) {
  this.adaptee = adaptee;
 }
 public void itemStateChanged(ItemEvent e) {
  adaptee.cboMonth_itemStateChanged(e);
 }
}