源代码下载：点击下载源代码
用xml存储中国各大城市的数据。
xml数据太多了就不贴上了，贴个图片：
要解释xml，添加了一个jdom.jar，上面的源代码下载里面有。
解释xml的类：
package com.qiantu.component; import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List; import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory; import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException; public class XMLDao {
/**
* 根据某个城市获取此省市的所有地区
* @param districts
* @return
*/
public static List<String> getDistricts(String districts) {
List<String> list = new ArrayList<String>();
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
try {
factory.setIgnoringElementContentWhitespace(true); DocumentBuilder db = factory.newDocumentBuilder();
Document xmldoc = db.parse(new File("xml/Districts.xml"));
Element root = xmldoc.getDocumentElement(); NodeList nodes = selectNodes("//District[@city='"+districts+"']", root);
for(int i=0; i<nodes.getLength(); i++) {
Node node = nodes.item(i);
String name = node.getTextContent();
list.add(name);
}
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return list;
} /**
* 根据某个省份的名字获取此省份的所有城市
* @param provinces
* @return
*/
public static List<String> getCities(String provinces) {
List<String> list = new ArrayList<String>();
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
try {
factory.setIgnoringElementContentWhitespace(true); DocumentBuilder db = factory.newDocumentBuilder();
Document xmldoc = db.parse(new File("xml/Cities.xml"));
Element root = xmldoc.getDocumentElement(); NodeList nodes = selectNodes("//City[@Province='"+provinces+"']", root);
for(int i=0; i<nodes.getLength(); i++) {
Node node = nodes.item(i);
String name = node.getTextContent();
list.add(name);
}
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return list;
} /**
* 获取所有省份
* @return
*/
public static List<String> getProvinces() {
List<String> list = new ArrayList<String>();
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
try {
factory.setIgnoringElementContentWhitespace(true); DocumentBuilder db = factory.newDocumentBuilder();
Document xmldoc = db.parse(new File("xml/Provinces.xml"));
Element root = xmldoc.getDocumentElement(); NodeList nodes = selectNodes("/Provinces/Province", root);
for(int i=0; i<nodes.getLength(); i++) {
Node node = nodes.item(i);
String name = node.getTextContent();
list.add(name);
}
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return list;
} /**
* 根据xpath获取某一个节点
* @param express
* @param source
* @return
*/
public static Node selectSingleNode(String express, Object source) {// 查找节点，并返回第一个符合条件节点
Node result = null;
XPathFactory xpathFactory = XPathFactory.newInstance();
XPath xpath = xpathFactory.newXPath();
try {
result = (Node) xpath
.evaluate(express, source, XPathConstants.NODE);
} catch (XPathExpressionException e) {
e.printStackTrace();
} return result;
} /**
* 根据xpath获取符合条件的所有节点
* @param express
* @param source
* @return
*/
public static NodeList selectNodes(String express, Object source) {// 查找节点，返回符合条件的节点集。
NodeList result = null;
XPathFactory xpathFactory = XPathFactory.newInstance();
XPath xpath = xpathFactory.newXPath();
try {
result = (NodeList) xpath.evaluate(express, source,
XPathConstants.NODESET);
} catch (XPathExpressionException e) {
e.printStackTrace();
} return result;
}
}
实现三级联动的类：
package com.qiantu.component; import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.List; import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox; public class JComboboxOfChina {
private JComboBox combobox_privince;
private JComboBox combobox_city;
private JComboBox combobox_area;
private DefaultComboBoxModel model1 = new DefaultComboBoxModel();
private DefaultComboBoxModel model2 = new DefaultComboBoxModel();
private DefaultComboBoxModel model3 = new DefaultComboBoxModel(); public JComboboxOfChina() {
//设置省市区三级联动数据
//设置第一级数据，从xml里面获取数据
for(String str : XMLDao.getProvinces()) {
model1.addElement(str);
}
combobox_privince = new JComboBox(model1);
combobox_privince.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
JComboBox source = (JComboBox) evt.getSource();
//根据获取的省份找到它下面的级别的市
String provinces = (String) source.getSelectedItem();
List<String> cities = XMLDao.getCities(provinces);
model2.removeAllElements();
for (String str : cities) {
model2.addElement(str);
}
model3.removeAllElements();
for (String str : XMLDao.getDistricts(cities.get(0))) {
model3.addElement(str);
}
}
});
//设置二级数据
for (String str : XMLDao.getCities("北京市")) {
model2.addElement(str);
}
combobox_city = new JComboBox(model2);
combobox_city.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
JComboBox source = (JComboBox) evt.getSource();
String city = (String) source.getSelectedItem();
List<String> districts = XMLDao.getDistricts(city);
model3.removeAllElements();
for (String str : districts) {
model3.addElement(str);
}
}
});
//设置三级数据
for (String str : XMLDao.getDistricts("北京市")) {
model3.addElement(str);
}
combobox_area = new JComboBox(model3);
} public JComboBox getCombobox_privince() {
return combobox_privince;
} public JComboBox getCombobox_city() {
return combobox_city;
} public JComboBox getCombobox_area() {
return combobox_area;
}
}
一个调用的例子：
package com.qiantu.component;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.WindowConstants; public class TestJComboboxOfChina {
public static void main(String[] args) {
JFrame j = new JFrame();
j.setSize(300,300);
j.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
j.setLayout(null); //构建中国各大城市的三级联动下拉框
JComboboxOfChina box = new JComboboxOfChina(); //构造省级下拉框
JLabel label_privince = new JLabel("省份：");
label_privince.setBounds(50, 50, 50, 30);
JComboBox combobox_privince = box.getCombobox_privince();
combobox_privince.setBounds(100, 50, 150, 30);
j.add(label_privince);
j.add(combobox_privince); //构造市级下拉框
JLabel label_city = new JLabel("城市：");
label_city.setBounds(50, 100, 50, 30);
JComboBox combobox_city = box.getCombobox_city();
combobox_city.setBounds(100, 100, 150, 30);
j.add(label_city);
j.add(combobox_city); //构建区级下拉框
JLabel label_area = new JLabel("地区：");
label_area.setBounds(50, 150, 50, 30);
JComboBox combobox_area = box.getCombobox_area();
combobox_area.setBounds(100, 150, 150, 30);
j.add(label_area);
j.add(combobox_area); j.setVisible(true);
}
}