这次给大家带来使用ajax异步校验用户名是否存在，使用ajax异步校验用户名是否存在的注意事项有哪些，下面就是实战案例，一起来看一下。
使用ajax完成用户名是否存在异步校验:
1.事件触发:
* onblur
2.编写ajax代码:
* 项action中提交:传递username参数
3.编写action
* 接收username:模型驱动接收.
4.* 编写实体类
* user
* user.hbm.xml
* 配置到spring中.
5.编写dao
* 继承hibernatedaosupport
* 在配置中注入sessionfactory
6.编写service:
* 注入userdao
* 事务管理:
核心代码实现：
function checkusername(){
// 获得文件框值:
var username = document.getelementbyid(username).value;
// 1.创建异步交互对象
var xhr = createxmlhttp();
// 2.设置监听
xhr.onreadystatechange = function(){
if(xhr.readystate == 4){
if(xhr.status == 200){
document.getelementbyid(span1).innerhtml = xhr.responsetext;
}
}
}
// 3.打开连接
xhr.open(get,${pagecontext.request.contextpath}/user_findbyname.action?time=+new date().gettime()+&username=+username,true);
// 4.发送
xhr.send(null);
}
function createxmlhttp(){
var xmlhttp;
try{ // firefox, opera 8.0+, safari
xmlhttp=new xmlhttprequest();
}
catch (e){
try{// internet explorer
xmlhttp=new activexobject(msxml2.xmlhttp);
}
catch (e){
try{
xmlhttp=new activexobject(microsoft.xmlhttp);
}
catch (e){}
}
}
return xmlhttp;
}
public string findbyname() throws ioexception {
// 调用service进行查询:
user existuser = userservice.findbyusername(user.getusername());
// 获得response对象,项页面输出:
httpservletresponse response = servletactioncontext.getresponse();
response.setcontenttype(text/html;charset=utf-8);
// 判断
if (existuser != null) {
// 查询到该用户:用户名已经存在
response.getwriter().println(<font color='red'>用户名已经存在</font>);
} else {
// 没查询到该用户:用户名可以使用
response.getwriter().println(<font color='green'>用户名可以使用</font>);
}
return none;
}
private userdao userdao;
public void setuserdao(userdao userdao) {
this.userdao = userdao;
}
// 按用户名查询用户的方法:
public user findbyusername(string username){
return userdao.findbyusername(username);
}
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;
}
<?xml version="1.0" encoding="utf-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemalocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd">
<!-- 配置连接池: -->
<!-- 引入外部属性文件 -->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!-- 配置c3p0连接池: -->
<bean id="datasource" class="com.mchange.v2.c3p0.combopooleddatasource">
<property name="driverclass" value="${jdbc.driver}"/>
<property name="jdbcurl" value="${jdbc.url}"/>
<property name="user" value="${jdbc.user}"/>
<property name="password" value="${jdbc.password}"/>
</bean>
<!-- hibernate的相关信息 -->
<bean id="sessionfactory" class="org.springframework.orm.hibernate3.localsessionfactorybean">
<!-- 注入连接池 -->
<property name="datasource" ref="datasource"/>
<!-- 配置hibernate的其他的属性 -->
<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>
</bean>
<!-- 事务管理: -->
<!-- 事务管理器 -->
<bean id="transactionmanager" class="org.springframework.orm.hibernate3.hibernatetransactionmanager">
<property name="sessionfactory" ref="sessionfactory"/>
</bean>
<!-- 开启注解事务 -->
<tx:annotation-driven transaction-manager="transactionmanager"/>
<!-- action的配置 ===========================-->
<!-- 首页访问的action -->
<bean id="indexaction" class="cn.itcast.shop.index.action.indexaction" scope="prototype">
</bean>
<!-- 配置验证码action -->
<bean id="checkimgaction" class="cn.itcast.shop.user.action.checkimgaction" scope="prototype">
</bean>
<!-- 用户模块的action -->
<bean id="useraction" class="cn.itcast.shop.user.action.useraction" scope="prototype">
<!-- 注入service -->
<property name="userservice" ref="userservice"/>
</bean>
<!-- service的配置 ===========================-->
<bean id="userservice" class="cn.itcast.shop.user.service.userservice">
<property name="userdao" ref="userdao"/>
</bean>
<!-- dao的配置 ===========================-->
<bean id="userdao" class="cn.itcast.shop.user.dao.userdao">
<property name="sessionfactory" ref="sessionfactory"/>
</bean>
</beans>
[html] view plain copy 在code上查看代码片派生到我的代码片
<?xml version="1.0" encoding="utf-8" ?>
<!doctype struts public
"-//apache software foundation//dtd struts configuration 2.3//en"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<constant name="struts.devmode" value="false" />
<constant name="struts.enable.dynamicmethodinvocation" value="true"/>
<package name="shop" extends="struts-default" namespace="/">
<global-results>
<result name="msg">/web-inf/jsp/msg.jsp</result>
</global-results>
<!-- 配置首页访问的action -->
<action name="index" class="indexaction">
<result name="index">/web-inf/jsp/index.jsp</result>
</action>
<!-- 配置用户模块的action -->
<action name="user_*" class="useraction" method="{1}">
<result name="registpage">/web-inf/jsp/regist.jsp</result>
<result name="input">/web-inf/jsp/regist.jsp</result>
<result name="loginpage">/web-inf/jsp/login.jsp</result>
<result name="login">/web-inf/jsp/login.jsp</result>
<result name="loginsuccess" type="redirectaction">index</result>
<result name="quit" type="redirectaction">index</result>
<result name="checkcodefail">/web-inf/jsp/regist.jsp</result>
</action>
<!-- 验证码action -->
<action name="checkimg" class="checkimgaction"></action>
</package>
</struts>
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