//:ComboBoxText.java
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import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
public class ComboBoxText {
private String[][] xxx = {
{"浙江","杭州","温州","绍兴","舟山",},
{"江苏","南京","无锡","徐州","蒙眬",},
{"上海","闵行区","普陀区","金山区",},
};
private Object[] a(){
Object[] os = new Object[xxx.length];
for(int i=0; ixxx.length; i++){
os[i]=xxx[i][0];
}
return os;
}
private Object[] b(Object a){
for(int i=0; ixxx.length; i++){
if(xxx[i][0].equals(a)){
Object[] o = new Object[xxx[i].length-1];
for(int j=0; jo.length; j++)
o[j]=xxx[i][j+1];
return o;
}
}
return new Object[]{};
}
public static void main(String[] args) {
final ComboBoxText ct = new ComboBoxText();
final JComboBox ca = new JComboBox(ct.a());
final JComboBox cb = new JComboBox();
ca.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
cb.removeAllItems();
Object selected = ca.getSelectedItem();
Object[] newItems = ct.b(selected);
for(int i=0; inewItems.length; i++)
cb.addItem(newItems[i]);
}
});
ca.setSelectedIndex(-1);
JFrame f = new JFrame();f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().setLayout(new FlowLayout(FlowLayout.LEFT));
f.add(ca);f.add(cb);f.setVisible(true);
f.setSize(200,100);
}
}
这里也只能是给你个概念，要是要真的去做，就必须要有实例来做。首先AJAX简单说就是用一个网页刷新另一个网页的其中的某些部分（例如div标签），AJAX是异步传输的，也就是当你点击一个按钮后，不需要跳转整个页面，AJAX会帮你把你提交的数据发到服务器端，验证或运算完后返回你操作的页面，并局部刷新页面。至于3级联动，我想你说的应该是你点了一下某个控件，第二个控件和第三个控件会随之改变内容，这样的话，也就是点第一个控件的时候会发送数据到服务器，等运算完后返回后刷新第2第3个控件的内容……
以省，市，城联动为例：
此小程序的功能主要是采用异步请求方式从数据库中调取省市区信息显示到下拉列表：
代码如下：
建立数据库中的代码和一些配置文件信息就省略了，主要有JavaScript中的代码为：
$(document).ready(function(){
$.get("getProvince.do", function(result){
$("#showp").html(result);
});
})
var xmlhttp;
function mysend(str){
$(document).ready(function(){
$("#show2").html("");
})
var show = document.getElementByIdx_x_x_x_x_x_x_x_x_x("show");
show.innerHTML = "";
var province = document.getElementByIdx_x_x_x_x_x_x_x_x_x("province").value;
if(province!=0){
if(window.XMLHttpRequest){
xmlhttp = new XMLHttpRequest();
}else{
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function(){
if(xmlhttp.readyState==4 xmlhttp.status==200){
show.innerHTML = xmlhttp.responseText;
}
}
var ss = encodeURIComponent(str);
xmlhttp.open("GET","getCity.do?provinceid="+ss,true);
xmlhttp.send(null);
}
}
function myarea(str){
if(window.XMLHttpRequest){
xmlhttp = new XMLHttpRequest();
}else{
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function(){
if(xmlhttp.readyState==4 xmlhttp.status==200){
var show2 = document.getElementByIdx_x_x_x_x_x_x_x_x_x("show2");
show2.innerHTML = xmlhttp.responseText;
}
}
var ss = encodeURIComponent(str);
xmlhttp.open("GET","getArea.do?cityid="+ss,true);
xmlhttp.send(null);
}
html页面中的代码为：
所在地
action中的代码为：
package mobi.zhangsheng.jiejia.action;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import org.springframework.stereotype.Controller;
import mobi.zhangsheng.jiejia.domain.Areas;
import mobi.zhangsheng.jiejia.service.AgentsService;
import mobi.zhangsheng.jiejia.service.AreasService;
@Controller
public class ProvinceAction {
private int provinceid;
private int cityid;
@Resource
private AreasService as;
@Resource
private AgentsService ags;
public int getProvinceid() {
return provinceid;
}
public void setProvinceid(int provinceid) {
this.provinceid = provinceid;
}
public int getCityid() {
return cityid;
}
public void setCityid(int cityid) {
this.cityid = cityid;
}
public void getProvince(){
List provinceList = as.getAreasPrvinceList();
HttpServletResponse resp= ServletActionContext.getResponse();
HttpServletRequest request = ServletActionContext.getRequest();
//resp.setContentType("xml");
resp.setContentType("text/html");
resp.setCharacterEncoding("utf-8");
try {
PrintWriter out = resp.getWriter();
out.print("");
//out.print("shanghai");
} catch (IOException e) {
e.printStackTrace();
}
}
public void getCity(){
List cityList = as.getAreasCityList(provinceid);
HttpServletResponse resp= ServletActionContext.getResponse();
//resp.setContentType("xml");
resp.setContentType("text/html");
resp.setCharacterEncoding("utf-8");
try {
PrintWriter out = resp.getWriter();
out.print("");
//out.print("shanghai");
} catch (IOException e) {
e.printStackTrace();
}
}
public void getArea(){
List areaList = as.getAreasCityList(cityid);
if(areaList.size()==0){
}else{
HttpServletResponse resp= ServletActionContext.getResponse();
resp.setContentType("text/html");
resp.setCharacterEncoding("utf-8");
try {
PrintWriter out = resp.getWriter();
out.print("");
} catch (IOException e) {
e.printStackTrace();
}
}
}
}