小伙伴在上網(wǎng)的時候,需要下載或者觀看某些視頻資料,更或者是在逛淘寶的時候,我們都需要注冊一個用戶,當我們填寫好各種信息,點擊確定的時候,提示用戶名已經(jīng)存在,小編就想,為什么當我們填寫完用戶名的時候,她就自動提示用戶名已經(jīng)存在,我們也不需要浪費那么多感情,直到填寫完那么多的信息之后在提示,在小編最近的項目中,就碰到這個問題,我們可以使用ajax完成用戶名是否存在,今天這篇博客,小編就簡單的總結(jié)一下,如何使用ajax來完成校驗,還請小伙伴多多指教哦`(*∩_∩*)′!
首先ajax完成用戶名是否存在異步校驗,那么我們該如何做呢?在這里,我們要由事件進行觸發(fā),也就是說,我們在用戶名里面輸入的時候,鼠標移開,這個事件叫做onblur,即失去焦點,與其相對的,鼠標放在里面獲得焦點,我們稱之為onfocus,那么失去焦點,我們該怎么操作呢?首先找到注冊頁面,在注冊頁面找到用戶名那部分的代碼,在后面加上onblur=checkUsername(),校驗用戶名即可,接著我們來編寫方法checkUsername,具體代碼如下所示:
span style="font-size:18px;">function checkUsername() {
//獲取文本框值:
var username = document.getElementById("username").value;
//1、創(chuàng)建異步交互對象
var xhr = createXmlHttp();
//2、設(shè)置監(jiān)聽
xhr.onreadystatechange = function() {
if (xhr.readyState == 4) {
if (xhr.status == 200) {
document.getElementById("span1").innerHTML = xhr.responseText;
}
}
}
//3、打開連接
xhr.open("GET",
"${pageContext.request.contextPath}/user_findByName.action?time="
+ new Date().getTime() + "username=", true)
//4、發(fā)送
xhr.send(null);
}
function createXmlHttp() {
var xmlHttp;
try {
xmlHttp = new XMLHttpRequest();
}
catch (e) {
try {
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
return xmlHttp;
}
/span>
接著,我們來建立實體Vo,實現(xiàn)模型驅(qū)動,自動實現(xiàn)封裝,具體代碼如下所示:
span style="font-size:18px;">package cn.itcast.shop.user.vo;
public class User {
private Integer uid;
private String username;
private String password;
private String name;
private String email;
private String phone;
private String addr;
private Integer state;
private String code;
public Integer getUid() {
return uid;
}
public void setUid(Integer uid) {
this.uid = uid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getAddr() {
return addr;
}
public void setAddr(String addr) {
this.addr = addr;
}
public Integer getState() {
return state;
}
public void setState(Integer state) {
this.state = state;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
}/span>
我們要接收參數(shù),實現(xiàn)模型驅(qū)動,ActionSupport直接實現(xiàn)modelDriven即可,接著來編寫我們的ajax代碼,需要向action中進行提交,我們來編寫UserAction中的代碼,具體代碼如下所示:
span style="font-size:18px;">package cn.itcast.shop.user.action;
import java.io.IOException;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import cn.itcast.shop.user.service.UserService;
import cn.itcast.shop.user.vo.User;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
/**
* 用戶模塊Action的類
* @author Flower
*
*/
public class UserAction extends ActionSupport implements ModelDrivenUser> {
//模型驅(qū)動使用的對象
private User user = new User();
public User getModel(){
return user;
}
//注入UserService
private UserService userService;
public void setUserService(UserService userService){
this.userService=userService;
}
/**
* 跳轉(zhuǎn)到注冊頁面的執(zhí)行方法
*/
public String registPage(){
return "registPage";
}
/**
* ajax進行異步校驗用戶名的執(zhí)行方法
* @throws IOException
*/
public String findByName() throws IOException{
//調(diào)用Service進行查詢
User existUser = userService.findByUsername(user.getUsername());
//獲得response對象,向頁面輸出
HttpServletResponse response = ServletActionContext.getResponse();
response.setContentType("text/html;charset=UTF-8");
//判斷
if(existUser != null){
//查詢到該用戶:用戶名已經(jīng)存在
response.getWriter().println("font color='red'>用戶名已經(jīng)存在/font>");
}else{
//沒查詢到該用戶:用戶名可以使用
response.getWriter().println("font color='green'>用戶名已經(jīng)存在/font>");
}
return NONE;
}
/**
* 用戶注冊的方法:
*/
public String regist(){
return NONE;
}
}
/span>
接著,我們需要做的就是把service和Dao配置到applicationContext中,代碼如下所示:
span style="font-size:18px;">!-- Service的配置 =========================== -->
bean id="userService" class="cn.itcast.shop.user.service.UserService">
property name="userDao" ref="userDao"/>
/bean>
!-- UserDao的配置 =========================== -->
bean id="userDao" class="cn.itcast.shop.user.dao.UserDao">
property name="sessionFactory" ref="sessionFactory">/property>
/bean> /span>
配置好了之后,我們需要在UserDao里面完成查詢,具體代碼如下所示:
span style="font-size:18px;">package cn.itcast.shop.user.dao;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
import java.util.List;
import cn.itcast.shop.user.vo.User;
/**
* 用戶模塊持久層代碼
* @author Flower
*
*/
public class UserDao extends HibernateDaoSupport {
//按名次查詢是否有該用戶
public User findByUsername (String username){
String hql ="from User where username= ?";
List User> list=this.getHibernateTemplate().find(hql,username);
if(list !=null list.size() > 0){
return list.get(0);
}
return null;
}
}
/span>
接著,我們需要在service里面完成對Dao的調(diào)用,具體代碼如下所示:
span style="font-size:18px;">package cn.itcast.shop.user.service;
import org.springframework.transaction.annotation.Transactional;
import cn.itcast.shop.user.dao.UserDao;
import cn.itcast.shop.user.vo.User;
/**
* 用戶模塊業(yè)務(wù)層代碼
* @author Flower
*
*/
@Transactional
public class UserService {
//注入UserDao
private UserDao userDao;
public void setUserDao(UserDao userDao){
this.userDao =userDao;
}
//按用戶名查詢用戶的方法
public User findByUsername (String username){
return userDao.findByUsername(username);
}
}
/span>
接著我們需要在UserAction中進行調(diào)用,具體代碼如下所示:
span style="font-size:18px;">package cn.itcast.shop.user.action;
import java.io.IOException;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import cn.itcast.shop.user.service.UserService;
import cn.itcast.shop.user.vo.User;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
/**
* 用戶模塊Action的類
* @author Flower
*
*/
public class UserAction extends ActionSupport implements ModelDrivenUser> {
//模型驅(qū)動使用的對象
private User user = new User();
public User getModel(){
return user;
}
//注入UserService
private UserService userService;
public void setUserService(UserService userService){
this.userService=userService;
}
/**
* 跳轉(zhuǎn)到注冊頁面的執(zhí)行方法
*/
public String registPage(){
return "registPage";
}
/**
* ajax進行異步校驗用戶名的執(zhí)行方法
* @throws IOException
*/
public String findByName() throws IOException{
//調(diào)用Service進行查詢
User existUser = userService.findByUsername(user.getUsername());
//獲得response對象,向頁面輸出
HttpServletResponse response = ServletActionContext.getResponse();
response.setContentType("text/html;charset=UTF-8");
//判斷
if(existUser != null){
//查詢到該用戶:用戶名已經(jīng)存在
response.getWriter().println("font color='red'>用戶名已經(jīng)存在/font>");
}else{
//沒查詢到該用戶:用戶名可以使用
response.getWriter().println("font color='green'>用戶名已經(jīng)存在/font>");
}
return NONE;
}
/**
* 用戶注冊的方法:
*/
public String regist(){
return NONE;
}
}
/span>
最后,我們來編寫映射文件里面的內(nèi)容,具體代碼如下所示:
span style="font-size:18px;">?xml version="1.0" encoding="UTF-8"?>
!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
hibernate-mapping>
class name="cn.itcast.shop.user.vo.User" table="user">
id name="uid">
generator class="native"/>
/id>
property name="username"/>
property name="password"/>
property name="name"/>
property name="email"/>
property name="phone"/>
property name="addr"/>
property name="state"/>
property name="code"/>
/class>
/hibernate-mapping>/span>
不要忘記了,要把她陪到applicationContext里面,具體代碼如下所示:
span style="font-size:18px;">!-- 配置Hibernate的其他的屬性 -->
property name="hibernateProperties">
props>
prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect/prop>
prop key="hibernate.show_sql">true/prop>
prop key="hibernate.format_sql">true/prop>
prop key="hibernate.connection.autocommit">false/prop>
prop key="hibernate.hbm2ddl.auto">update/prop>
/props>
/property>
!-- 配置Hibernate的映射文件 -->
property name="mappingResources">
list>
value>cn/itcast/shop/user/vo/User.hbm.xml/value>
/list>
/property>
/span>
代碼到此結(jié)束,下面給大家展示下效果圖:
小編總結(jié):
實現(xiàn)的思路是這樣滴`(*∩_∩*)′,首先是由onblur進行事件觸發(fā),第二,編寫ajax的代碼,向action中提交,傳遞參數(shù)username,第三步,編寫action,接收username,實現(xiàn)模型驅(qū)動配置到spring中,第四步,編寫DAO,集成HibernateDaoSupport,在配置中注入sessionFactory,最后編寫Service,注入UserDao,還有事務(wù)管理,一個簡單的demo,還請小伙伴多多指教,SSH網(wǎng)上商城,精彩未完待續(xù)~~~
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