使用AJAX完成用户名是否存在异步校验


            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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