Map集合可以保存键值映射关系，这非常适合本实例所需要的数据结构，所有省份信息可以保存为Map集合的键，而每个键可以保存对应的城市信息，本实例就是利用Map集合实现了省市级联选择框，当选择省份信息时，将改变城市下拉选择框对应的内容。
思路分析：
1. 创建全国（省，直辖市，自治区）映射集合，即LinkedHashMap对象，使用Map接口的put()方法向集合中添加指定的省与城市的映射关系，其中值为String型一维数组。
代码如下：
CityMap.java
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import java.util.LinkedHashMap;import java.util.Map;public class CityMap { /** * 全国（省，直辖市，自治区）映射集合 */ public
static Map<String,String[]> model=new
LinkedHashMap<String, String[]>(); static{ model.put("北京", new
String[]{"北京"}); model.put("上海", new
String[]{"上海"}); model.put("天津", new
String[]{"天津"}); model.put("重庆", new
String[]{"重庆"}); model.put("黑龙江", new
String[]{"哈尔滨","齐齐哈尔","牡丹江","大庆","伊春","双鸭山","鹤岗","鸡西","佳木斯","七台河","黑河","绥化","大兴安岭"}); model.put("吉林", new
String[]{"长春","延边","吉林","白山","白城","四平","松原","辽源","大安","通化"}); model.put("辽宁", new
String[]{"沈阳","大连","葫芦岛","旅顺","本溪","抚顺","铁岭","辽阳","营口","阜新","朝阳","锦州","丹东","鞍山"}); model.put("内蒙古", new
String[]{"呼和浩特","呼伦贝尔","锡林浩特","包头","赤峰","海拉尔","乌海","鄂尔多斯","通辽"}); model.put("河北", new
String[]{"石家庄","唐山","张家口","廊坊","邢台","邯郸","沧州","衡水","承德","保定","秦皇岛"}); model.put("河南", new
String[]{"郑州","开封","洛阳","平顶山","焦作","鹤壁","新乡","安阳","濮阳","许昌","漯河","三门峡","南阳","商丘","信阳","周口","驻马店"}); model.put("山东", new
String[]{"济南","青岛","淄博","威海","曲阜","临沂","烟台","枣庄","聊城","济宁","菏泽","泰安","日照","东营","德州","滨州","莱芜","潍坊"}); model.put("山西", new
String[]{"太原","阳泉","晋城","晋中","临汾","运城","长治","朔州","忻州","大同","吕梁"}); model.put("江苏", new
String[]{"南京","苏州","昆山","南通","太仓","吴县","徐州","宜兴","镇江","淮安","常熟","盐城","泰州","无锡","连云港","扬州","常州","宿迁"}); model.put("安徽", new
String[]{"合肥","巢湖","蚌埠","安庆","六安","滁州","马鞍山","阜阳","宣城","铜陵","淮北","芜湖","毫州","宿州","淮南","池州"}); model.put("陕西", new
String[]{"西安","韩城","安康","汉中","宝鸡","咸阳","榆林","渭南","商洛","铜川","延安"}); model.put("宁夏", new
String[]{"银川","固原","中卫","石嘴山","吴忠"}); model.put("甘肃", new
String[]{"兰州","白银","庆阳","酒泉","天水","武威","张掖","甘南","临夏","平凉","定西","金昌"}); model.put("青海", new
String[]{"西宁","海北","海西","黄南","果洛","玉树","海东","海南"}); model.put("湖北", new
String[]{"武汉","宜昌","黄冈","恩施","荆州","神农架","十堰","咸宁","襄樊","孝感","随州","黄石","荆门","鄂州"}); model.put("湖南", new
String[]{"长沙","邵阳","常德","郴州","吉首","株洲","娄底","湘潭","益阳","永州","岳阳","衡阳","怀化","韶山","张家界"}); model.put("浙江", new
String[]{"杭州","湖州","金华","宁波","丽水","绍兴","雁荡山","衢州","嘉兴","台州","舟山","温州"}); model.put("江西", new
String[]{"南昌","萍乡","九江","上饶","抚州","吉安","鹰潭","宜春","新余","景德镇","赣州"}); model.put("福建", new
String[]{"福州","厦门","龙岩","南平","宁德","莆田","泉州","三明","漳州"}); model.put("贵州", new
String[]{"贵阳","安顺","赤水","遵义","铜仁","六盘水","毕节","凯里","都匀"}); model.put("四川", new
String[]{"成都","泸州","内江","凉山","阿坝","巴中","广元","乐山","绵阳","德阳","攀枝花","雅安","宜宾","自贡","甘孜州","达州","资阳","广安","遂宁","眉山","南充"}); model.put("广东", new
String[]{"广州","深圳","潮州","韶关","湛江","惠州","清远","东莞","江门","茂名","肇庆","汕尾","河源","揭阳","梅州","中山","德庆","阳江","云浮","珠海","汕头","佛山"}); model.put("广西", new
String[]{"南宁","桂林","阳朔","柳州","梧州","玉林","桂平","贺州","钦州","贵港","防城港","百色","北海","河池","来宾","崇左"}); model.put("云南", new
String[]{"昆明","保山","楚雄","德宏","红河","临沧","怒江","曲靖","思茅","文山","玉溪","昭通","丽江","大理"}); model.put("海南", new
String[]{"海口","三亚","儋州","琼山","通什","文昌"}); model.put("新疆", new
String[]{"乌鲁木齐","阿勒泰","阿克苏","昌吉","哈密","和田","喀什","克拉玛依","石河子","塔城","库尔勒","吐鲁番","伊宁"}); }} |
2. 定义获取省份的方法，创建一个Map集合，将上一步得到的映射集合赋值给它，使用Map集合的keySet()方法获取该集合中的所有键对象组成的Set集合，即为省分集合，创建一个Object型一维数组，使用Set接口的toArray()方法将Set集合转换为数组，返回此数组作为省份选择下拉列表的参数。
3. 使用JComboBox类的setModel()方法为省份下拉列表添加省份信息，参数即为上一步中的获取省份方法。
4. 定义根据省份获取市/县的方法，创建一个Map集合，将步骤1中得到的映射集合赋值给它，使用Map集合的get()方法获取指定键的值，即为市/县集合，创建一个String[]型一维数组，将市/县集合赋值给该数组。
5. 定义省份下拉列表的选项状态更改事件，在该事件中通过JComboBox类的getSelectedItem()方法获取选中的省份，默认为省份集合中的第一个值，然后使用JComboBox类的removeAllItems()方法清空市/县列表，根据选中的省份获取市/县数组，最后使用JComboBox的setModel()方法重新添加市/县列表的值。
代码如下：
BackgroundPanel.java
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import java.awt.Graphics;import java.awt.Image;import javax.swing.JPanel;/** * 带背景的面板组件 * * @author ZhongWei Lee */public
class BackgroundPanel extends
JPanel { /** * */ private
static final long serialVersionUID = 7758689434195492602L; /** * 背景图片 */ private
Image image; /** * 构造方法 */ public
BackgroundPanel() { super(); setOpaque(false); setLayout(null); } /** * 设置图片的方法 */ public
void setImage(Image image) { this.image = image; } @Override protected
void paintComponent(Graphics g) {// 重写绘制组件外观 if
(image != null) { int
width = getWidth();// 获取组件大小 int
height = getHeight(); g.drawImage(image, 0, 0, width, height, this);// 绘制图片与组件大小相同 } super.paintComponent(g);// 执行超类方法 }} |
SwingResourceManager.java
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import java.awt.Image;import java.awt.Toolkit;import java.io.BufferedInputStream;import java.io.ByteArrayOutputStream;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.util.HashMap;import java.util.Iterator;import
javax.swing.ImageIcon;/** * Utility class for managing resources such as colors, fonts, images, etc. * * This class may be freely distributed as part of any application or plugin. * <p> * Copyright (c) 2003 - 2004, Instantiations, Inc. <br>All Rights Reserved * * @author scheglov_ke */public
class SwingResourceManager { /** * Maps image names to images */ private
static HashMap<String, Image> m_ClassImageMap = new
HashMap<String, Image>(); /** * Returns an image encoded by the specified input stream * @param is InputStream The input stream encoding the image data * @return Image The image encoded by the specified input stream */ private
static Image getImage(InputStream is) { try
{ ByteArrayOutputStream baos = new
ByteArrayOutputStream(); byte
buf[] = new
byte[1024
* 4]; while
(true) { int
n = is.read(buf); if
(n == -1) break; baos.write(buf, 0, n); } baos.close(); return
Toolkit.getDefaultToolkit().createImage(baos.toByteArray()); } catch
(Throwable e) { return
null; } } /** * Returns an image stored in the file at the specified path relative to the specified class * @param clazz Class The class relative to which to find the image * @param path String The path to the image file * @return Image The image stored in the file at the specified path */ public
static Image getImage(Class<?> clazz, String path) { String key = clazz.getName() + ‘|‘
+ path; Image image = m_ClassImageMap.get(key); if
(image == null) { if
((path.length() > 0) && (path.charAt(0) == ‘/‘)) { String newPath = path.substring(1, path.length()); image = getImage(new
BufferedInputStream(clazz.getClassLoader().getResourceAsStream(newPath))); } else
{ image = getImage(clazz.getResourceAsStream(path)); } m_ClassImageMap.put(key, image); } return
image; } /** * Returns an image stored in the file at the specified path * @param path String The path to the image file * @return Image The image stored in the file at the specified path */ public
static Image getImage(String path) { return
getImage("default", path); //$NON-NLS-1$ } /** * Returns an image stored in the file at the specified path * @param section String The storage section in the cache * @param path String The path to the image file * @return Image The image stored in the file at the specified path */ public
static Image getImage(String section, String path) { String key = section + ‘|‘
+ SwingResourceManager.class.getName() + ‘|‘
+ path; Image image = m_ClassImageMap.get(key); if
(image == null) { try
{ FileInputStream fis = new
FileInputStream(path); image = getImage(fis); m_ClassImageMap.put(key, image); fis.close(); } catch
(IOException e) { return
null; } } return
image; } /** * Clear cached images in specified section * @param section the section do clear */ public
static void clearImages(String section) { for
(Iterator<String> I = m_ClassImageMap.keySet().iterator(); I.hasNext();) { String key = I.next(); if
(!key.startsWith(section + ‘|‘)) continue; Image image = m_ClassImageMap.get(key); image.flush(); I.remove(); } } /** * Returns an icon stored in the file at the specified path relative to the specified class * @param clazz Class The class relative to which to find the icon * @param path String The path to the icon file * @return Icon The icon stored in the file at the specified path */ public
static ImageIcon getIcon(Class<?> clazz, String path) { return
getIcon(getImage(clazz, path)); } /** * Returns an icon stored in the file at the specified path * @param path String The path to the icon file * @return Icon The icon stored in the file at the specified path */ public
static ImageIcon getIcon(String path) { return
getIcon("default", path); //$NON-NLS-1$ } /** * Returns an icon stored in the file at the specified path * @param section String The storage section in the cache * @param path String The path to the icon file * @return Icon The icon stored in the file at the specified path */ public
static ImageIcon getIcon(String section, String path) { return
getIcon(getImage(section, path)); } /** * Returns an icon based on the specified image * @param image Image The original image * @return Icon The icon based on the image */ public
static ImageIcon getIcon(Image image) { if
(image == null) return
null; return
new ImageIcon(image); }} |
MainFrame.java
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import java.awt.EventQueue;import java.awt.event.ItemEvent;import java.awt.event.ItemListener;import java.util.Map;import java.util.Set;import javax.swing.DefaultComboBoxModel;import javax.swing.JButton;import javax.swing.JComboBox;import
javax.swing.JFrame;import
javax.swing.JLabel;import
javax.swing.JPanel;import
javax.swing.JTextField;import
javax.swing.SwingConstants;import
javax.swing.UIManager;import
javax.swing.border.TitledBorder;public
class MainFrame extends
JFrame { /** * */ private
static final long serialVersionUID = -4595347311922711984L; private
JTextField textField_3; private
JTextField textField_1; private
JComboBox comboBox_1; private
JTextField textField; private
JComboBox cityComboBox; private
JComboBox comboBox; /** * Launch the application * * @param args */ public
static void main(String args[]) { EventQueue.invokeLater(new
Runnable() { public
void run() { try
{ UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"); MainFrame frame = new
MainFrame(); frame.setVisible(true); } catch
(Exception e) { e.printStackTrace(); } } }); } /** * Create the frame */ public
MainFrame() { getContentPane().setLayout(null); setBounds(100, 100, 518, 379); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //获取默认的市/县 String province=(String)getProvince()[0]; setTitle("输入指定省/直辖市查询对应的市县"); final
BackgroundPanel backgroundPanel = new
BackgroundPanel(); backgroundPanel.setImage(SwingResourceManager.getImage(MainFrame.class, "/images/background.jpg")); backgroundPanel.setBounds(0, 0, 510, 380); getContentPane().add(backgroundPanel); final
JPanel panel = new
JPanel(); panel.setOpaque(false); panel.setBounds(36, 126, 438, 70); backgroundPanel.add(panel); panel.setLayout(null); panel.setBorder(new
TitledBorder(null, "居住地", TitledBorder.DEFAULT_JUSTIFICATION, TitledBorder.DEFAULT_POSITION, null, null)); cityComboBox = new
JComboBox(); cityComboBox.setBounds(245, 25, 124, 27); panel.add(cityComboBox); cityComboBox.setModel(new
DefaultComboBoxModel(getCity(province))); comboBox = new
JComboBox(); comboBox.setBounds(25, 25, 124, 27); panel.add(comboBox); comboBox.addItemListener(new
ItemListener() { public
void itemStateChanged(final
ItemEvent e) { // 选项状态更改事件 itemChange(); } }); comboBox.setModel(new
DefaultComboBoxModel(getProvince())); // 添加省份信息 final
JLabel label = new
JLabel(); label.setText("省/直辖市"); label.setBounds(155, 30, 66, 18); panel.add(label); final
JLabel label_1 = new
JLabel(); label_1.setText("市/县"); label_1.setBounds(375, 30, 37, 18); panel.add(label_1); final
JLabel label_2 = new
JLabel(); label_2.setBounds(36, 43, 65, 18); backgroundPanel.add(label_2); label_2.setHorizontalAlignment(SwingConstants.RIGHT); label_2.setHorizontalTextPosition(SwingConstants.LEADING); label_2.setText("姓 名："); textField = new
JTextField(); textField.setBounds(113, 38, 154, 28); backgroundPanel.add(textField); final
JLabel label_3 = new
JLabel(); label_3.setBounds(36, 84, 65, 18); backgroundPanel.add(label_3); label_3.setHorizontalAlignment(SwingConstants.RIGHT); label_3.setHorizontalTextPosition(SwingConstants.LEADING); label_3.setText("性 别："); comboBox_1 = new
JComboBox(); comboBox_1.setBounds(113, 81, 66, 25); backgroundPanel.add(comboBox_1); comboBox_1.setModel(new
DefaultComboBoxModel(new
String[] {"男", "女"})); final
JLabel label_4 = new
JLabel(); label_4.setBounds(36, 212, 65, 18); backgroundPanel.add(label_4); label_4.setHorizontalAlignment(SwingConstants.RIGHT); label_4.setHorizontalTextPosition(SwingConstants.LEADING); label_4.setText("详细地址："); textField_1 = new
JTextField(); textField_1.setBounds(113, 208, 367, 28); backgroundPanel.add(textField_1); final
JLabel label_4_1 = new
JLabel(); label_4_1.setBounds(36, 252, 65, 18); backgroundPanel.add(label_4_1); label_4_1.setHorizontalTextPosition(SwingConstants.LEADING); label_4_1.setHorizontalAlignment(SwingConstants.RIGHT); label_4_1.setText("E-mail："); textField_3 = new
JTextField(); textField_3.setBounds(113, 248, 367, 27); backgroundPanel.add(textField_3); final
JButton button = new
JButton(); button.setBounds(159, 289, 75, 28); backgroundPanel.add(button); button.setText("保存"); final
JButton button_1 = new
JButton(); button_1.setBounds(265, 289, 75, 28); backgroundPanel.add(button_1); button_1.setText("重置"); // } /** * 获取省、直辖市，自治区 * * @return */ public
Object[] getProvince() { Map<String, String[]> map = CityMap.model;// 获取省份信息保存到Map中 Set<String> set = map.keySet(); // 获取Map集合中的键，并以Set集合返回 Object[] province = set.toArray(); // 转换为数组 return
province; // 返回获取的省份信息 } /** * 获取指定省对应的市/县 * * @param selectProvince * @return */ public
String[] getCity(String selectProvince) { Map<String, String[]> map = CityMap.model; // 获取省份信息保存到Map中 String[] arrCity = map.get(selectProvince); // 获取指定键的值 return
arrCity; // 返回获取的市/县 } private
void itemChange() { String selectProvince = (String) comboBox.getSelectedItem(); cityComboBox.removeAllItems(); // 清空市/县列表 String[] arrCity = getCity(selectProvince); // 获取市/县 cityComboBox.setModel(new
DefaultComboBoxModel(arrCity)); // 重新添加市/县列表的值 }} |
效果如图：
原文：http://www.cnblogs.com/cysolo/p/3568084.html