Day10JavaWeb【Jquery案例】注册时用户名校验***-CFANZ编程社区

注册时用户名校验

Day10JavaWeb【Jquery案例】注册时用户名校验***_json数据

用户名注册时的校验分析

Day10JavaWeb【Jquery案例】注册时用户名校验***_js_02

(1)编写jsp页面的html表单

(2)编写jquery请求

(3)处理servlet的响应

web\register.jsp

<html>
<head>
    <title>Title</title>
    <%--    2 导入js编写发送请求的代码 --%>
<%--    <script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-3.3.1.js"></script>--%>
    <script type="text/javascript" src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
    <script type="text/javascript">$(function () {
            //页面加载成功
            //获取输入框
            $("#username").on("blur",function () {
                //获取输入的账号
                //alert($("#username").val())
                // 3 发送请求
                $.ajax({
                    url:"queryUsername",
                    async:true,
                    data:"username="+$("#username").val(),
                    type:"post",
                    dataType:"json",
                    success:function (data) {
                        //{"msg":"恭喜，该邮件地址可以注册","code":0}
                      // alert(data.code)
                       //alert(data.msg)
                        //5：根据服务端返回的json数据，编写显示逻辑
                        if(data.code == 0){
                            $("#msg").text(data.msg)

                            $("#msg").css("color","green")
                        }else{
                            $("#msg").text(data.msg)

                            $("#msg").css("color","red")
                        }
                    },
                    error:function () {
                        alert("服务器发生了错误")
                    }
                });
            })
        })</script>
</head>
<body>
        <!-- 1 显示表单 -->
        <form method="post" action="${pageContext.request.contextPath}/register">
           username: <input id="username" name="username" type="text"><br/>
            <div  id="msg"style="color: green;"></div>

           password: <input name="passowrd" type="password"><br/>
           <input  type="submit" value="注册"><br/>
        </form>
</body>
</html>

（3）编写 servlet

（1）返回的是json数据
（2）对象转成json数据
src\com\wzx\servlet\QueryServlet.java

//4:编写后台业务逻辑
@WebServlet("/queryUsername")
public class QueryServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1:接收请求获取参数
        String username = request.getParameter("username");
        //2:处理业务逻辑
        Result result = new Result();
        if("jack".equals(username)){
            //3:都需要是json数据
            result.setMsg("该邮箱地址已被注册");
            result.setCode(1);
            //返回已注册
        }else{
            result.setMsg("恭喜，该邮件地址可以注册");
            result.setCode(0);
            //返回未注册
        }
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().println(new ObjectMapper().writeValueAsString(result));

    }
}

src\com\wzx\servlet\Result.java

public class Result {
    private String msg;
    private int code;

    public Result(String msg, int code) {
        this.msg = msg;
        this.code = code;
    }

    public Result() {
    }
    //..
}