Ajax的核心是XMLHttpRequest对象(XHR)。XHR为向服务器发送请求和解析服务器响应提供了接口。能够以异步方式从服务器获取新数据。
jQuery.ajax(...) 常用参数:
- url:请求地址 type:请求方式,GET、POST(1.9.0之后用method)
- data:要发送的数据
- success:成功之后执行的回调函数(全局)
- error:失败之后执行的回调函数(全局)
使用Ajax简单的实现在输入框输入用户名和密码时,在不刷新页面的情况下去后台校验是否存在该用户。
效果:
首先还是先把SpringMVC的框架搭起来。
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<filter>
<filter-name>encoding</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
然后配置applicationContext.xml:
<?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:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.lyr.controller"/>
<mvc:default-servlet-handler/>
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8"/>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
<property name="failOnEmptyBeans" value="false"/>
</bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
登陆页面login.jsp:
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
<%--导入jquery--%>
<script src="${pageContext.request.contextPath}/statics/jquery-3.4.1.js"></script>
<script>
function a1() {
$.post({
url:"${pageContext.request.contextPath}/login",
data:{"name":$("#uname").val()},
success:function (data) {
if(data.toString()==='ok'){
console.log(data);
$("#nameinfo").css("color","green");
}else {
$("#nameinfo").css("color","red");
}
$("#nameinfo").html(data);
}
})
}
function a2() {
$.post({
url:"${pageContext.request.contextPath}/login",
data:{"pwd":$("#upwd").val()},
success:function (data) {
if(data.toString()==='ok'){
$("#pwdinfo").css("color","green");
}else {
$("#pwdinfo").css("color","red");
}
$("#pwdinfo").html(data);
}
})
}
</script>
</head>
<body>
<p>
用户名:<input type="text" id="uname" οnblur="a1()">
<span id="nameinfo"></span>
</p>
<p>
密码:<input type="text" id="upwd" οnblur="a2()">
<span id="pwdinfo"></span>
</p>
</body>
</html>
接下来就可以写controller类来进行数据的校验了
package com.lyr.controller;
import com.lyr.pojo.User;
import lombok.NoArgsConstructor;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
@RestController
public class myController {
@RequestMapping("/login")
public String login(String name,String pwd){
String msg="";
if(name!=null){
if ("admin".equals(name)){
msg="ok";
}else {
msg="用户名输入有误";
}
}
if (pwd != null) {
if ("123456".equals(pwd)){
msg="ok";
}else {
msg="密码输入有误";
}
}
return msg;
}
}
以后就可以用AJAX来实现在输入时校验用户信息了,只不过是把我上面controller类中固定的信息,改成从数据库获取用户信息然后进行校验的过程。