导入需要使用的包
c3p0 dbutil mysql
在jsp页面创建注册界面
用户名: 密码 邮箱 简介
在注册界面jsp中添加Ajax
这个代码是固定的,用来创建Ajax,就像jar包一样
<script type="text/javascript">
//1. 创建对象
function ajaxFunction(){
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;
}
以下代码是需要根据自己需要编写的
function checkUserName() {
//获取输入框的值 document 整个网页 根据id获取文本框的值
var name = document.getElementById("name").value;
//1. 创建对象
var request = ajaxFunction();
//2. 发送请求
request.open("POST" ,"/day16/CheckUserNameServlet" , true );
//注册状态改变监听,获取服务器传送过来的数据 如果等号左边成立就执行等号右边的值
request.onreadystatechange = function(){
//判断是否是4:请求已完成 ,并且是请求成功200
if(request.readyState == 4 && request.status == 200){
//获取后端发送过来的信息
var data = request.responseText;
if(data == 1){
//根据id向文本框内填入值
document.getElementById("span01").innerHTML = "<font color='red'>用户名已存在!</font>";
}else{
document.getElementById("span01").innerHTML = "<font color='green'>用户名可用!</font>";
}
}
}
request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
//向后端传值
request.send("name="+name);
}
</script>
完成servlet
response.setContentType("text/html;charset=utf-8");
String name = request.getParameter("name");
try {
checkdao check=new checkImpl();
boolean checkR=check.checkUsername(name);
if(checkR){
response.getWriter().println(1);
System.out.println(1);
}else{
response.getWriter().println(0);
System.out.println(0);
}
System.out.println( name+" "+checkR);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
完成dao和其实现类
QueryRunner queryRunner = new QueryRunner(new ComboPoolDataSource());
long query =(Long)queryRunner.query("select count(*) from user where username=?", new ScalarHandler(),username);
return query>0;
}
注意事项
post请求向后端传数据的时候必须要加上
request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
然后再向后端传值
request.send(“name=”+name);