这篇文章主要介绍“AJAX级联下拉框的实现方法”,在日常操作中,相信很多人在AJAX级联下拉框的实现方法问题上存在疑惑,小编查阅了各式资料,整理出简单好用的操作方法,希望对大家解答”AJAX级联下拉框的实现方法”的疑惑有所帮助!接下来,请跟着小编一起来学习吧!
需要的JAVA类
复制代码 代码如下:
package com.ajaxlab.ajax;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;
import com.ajaxlab.ajax.ProductClass;
public class ClassService {
private Document dom;
public ClassService(){
try{
SAXBuilder builder=new SAXBuilder();
this.dom=builder.build(ClassService.class.getResource("product.xml"));
}catch(Exception e){
e.printStackTrace();
}
}
public ProductClass[] getAllClass1(){
Collection products=new ArrayList();
Iterator iterator=this.dom.getRootElement().getChildren().iterator();
do{
Element element=(Element)iterator.next();
ProductClass product=new ProductClass(element.getAttributeValue("id"),
element.getAttributeValue("className"));
products.add(product);
}while(iterator.hasNext());
return (ProductClass[])products.toArray(new ProductClass[0]);
}
public ProductClass[] getAllClass2ById(String class1Id){
Collection products=new ArrayList();
Element classElement=null;
Iterator iterator=this.dom.getRootElement().getChildren().iterator();
do{
Element element=(Element)iterator.next();
if(class1Id.equalsIgnoreCase(element.getAttributeValue("id"))){
classElement=element;
break;
}
}while(iterator.hasNext());
if(classElement!=null){
Iterator iter=classElement.getChildren().iterator();
do{
Element element=(Element)iter.next();
ProductClass product=new ProductClass(element.getAttributeValue("id"),
element.getAttributeValue("className"));
products.add(product);
}while(iter.hasNext());
return (ProductClass[])products.toArray(new ProductClass[0]);
}
else{
return null;
}
}
public ProductClass[] getAllClass3ById(String class1Id,String class2Id) {
Collection products = new ArrayList();
Element class1Element = null;
Element class2Element = null;
Iterator iterator = this.dom.getRootElement().getChildren().iterator();
do {
Element element = (Element)iterator.next();
if(class1Id.equalsIgnoreCase(element.getAttributeValue("id"))) {
class1Element = element;
break;
}
}while(iterator.hasNext());
if(class1Element!=null) {
Iterator iter = class1Element.getChildren().iterator();
do {
Element element = (Element)iter.next();
if(class2Id.equalsIgnoreCase(element.getAttributeValue("id"))) {
class2Element = element;
break;
}
}while(iter.hasNext());
if(class2Element!=null) {
Iterator iter2 = class2Element.getChildren().iterator();
do {
Element element = (Element)iter2.next();
ProductClass product = new ProductClass(element.getAttributeValue("id"),element.getAttributeValue("className"));
products.add(product);
}while(iter2.hasNext());
}
return (ProductClass[])products.toArray(new ProductClass[0]);
}
else return null;
}
}
JSP:
(1)getClass.jsp 充当业务层供ajax调用
<%@ page contentType="text/html; charset=gb2312"%>
<%@ page import="com.ajaxlab.ajax.*"%>
<%
String class1Id = request.getParameter("class1Id");
String class2Id = request.getParameter("class2Id");
if("".equals(class1Id)) class1Id = null;
if("".equals(class2Id)) class2Id = null;
ClassService service = new ClassService();
if((class1Id!=null)&&(class2Id==null)) {
ProductClass[] classes = service.getAllClass2ById(class1Id);
if(classes!=null) {
for(int i=0;i
}
}
}
else if((class1Id!=null)&&(class1Id!=null)) {
ProductClass[] classes = service.getAllClass3ById(class1Id,class2Id);
if(classes!=null) {
for(int i=0;i
}
}
}
%>
(2)divmenu.jsp
<%@ page contentType="text/html; charset=gb2312"%>
<%@ page import="com.ajaxlab.ajax.*"%>
function doChange() {
var f = document.forms[0];
send_request("GET","getClass.jsp?class1Id="+f.select11.value+"&class2Id=",null,"TEXT",populateClass2);
}
function doChange2() {
var f = document.forms[0];
send_request("GET","getClass.jsp?class1Id="+f.select11.value+"&class2Id="+f.select12.value,null,"TEXT",populateClass3);
}
function populateClass2(){
var f=document.forms[0];
if(http_request.readystate==4){
if(http_request.status==200){
var list=http_request.responseText;
var classList=list.split("|");
f.select12.options.length=1;
for(var i=0;i
f.select12.add(new Option(temp[1],temp[0]));
}
}
}
}
function populateClass3(){
var f=document.forms[0];
if(http_request.readystate==4){
if(http_request.status==200){
var list=http_request.responseText;
var classList=list.split("|");
f.select13.options.length=1;
for(var i=0;i
f.select13.add(new Option(temp[1],temp[0]));
}
}
}
}
function LTrim(str)
{
var whitespace = new String(" /t/n/r");
var s = new String(str);
if (whitespace.indexOf(s.charAt(0)) != -1)
{
var j=0, i = s.length;
while (j < i && whitespace.indexOf(s.charAt(j)) != -1)
{
j++;
}
s = s.substring(j, i);
}
return s;
}
function RTrim(str)
{
var whitespace = new String(" /t/n/r");
var s = new String(str);
if (whitespace.indexOf(s.charAt(s.length-1)) != -1)
{
var i = s.length - 1;
while (i >= 0 && whitespace.indexOf(s.charAt(i)) != -1)
{
i--;
}
s = s.substring(0, i+1);
}
return s;
}
function Trim(str)
{
return RTrim(LTrim(str));
}
<%
ClassService service = new ClassService();
ProductClass[] classes = service.getAllClass1();
%>
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