Question

如何通过Ajax从动作类中获取JSP值？当我输入想要检查数据库的用户名时，用户名是否存在。为此，我正在使用Ajax。

这是我的JSP代码：

 $(document).ready(function(){
                $("#username").change(function(){
                    $("#message").html("checking...");          
                            $("#message").css('color', 'red');

                    var username=$("#username").val();
                    alert(username);

                    $.ajax({
                        type:"post",
                        url:"CheckUserAction",
                        data:"username="+username,
                        success:function(data){                        


//checking the code for username is present in database or not
                           }
        });
    });
    </script>
</head>

<body>
<%@include file="index.html" %>
 <div class="box2">
    <center>
    <!-- <div class="header"></div> -->
    <center>
        <div class="outer"><center>
        <br /><br /><br />
        <div class="inner"><br /><br /><br />
        <center> 
            <s:form action="RegisterationProcess" id="loginForm"  name="loginForm" method="post" >
                <table width="auto" border="0" align="center" cellpadding="2" cellspacing="0" class="tab">

                <tr>
                    <td colspan="2"><center><b>Registration Form</b></center></td>
                </tr>

                <tr>
                    <td colspan="2"><hr></td>
                </tr> 

                <input type="hidden" name="register" value="register"/>      
                <tr>     
                    <td><s:textfield name="user.userName"class="textfield" id="login" label="Name"/></td>
                </tr>

                <tr>  
                    <td><s:textfield name="user.userId" id="username"  class="textfield" label="User Name" /> </td> 
                    <div id="message"></div>        
                </tr>`enter code here`

                <tr>  
                    <td><s:password name="user.password"  class="textfield" id="password" label="Password" /></td>
                </tr>

                <tr>
                    <td><s:textfield name="user.emailId" class="textfield" id="emailAddress" label="Email" /></td>
                </tr>

                <tr>
                <td></td>
                <td><input id="sbmt" type="submit" value="Register"></td>
                <!-- <td><s:submit value="Register"  id="sbmt"/></td> -->
                </tr>

这是我的CheckUserAction课程：

      private String userId;
    private String userName;

  public UserImpl getUser()
    {
        return user;
    }

public void setUser(UserImpl user) 
{
    this.user = user;
}


public String getUserName() 
{
    return userName;
}

public void setUserName(String userName) 
{
    this.userName = userName;
}

public String getUserId()
{
    return userId;
}

public void setUserId(String userId) 
{
    this.userId = userId;
}

public String execute()
{
  System.out.println("username"+userName);
}
}

我的用户名为null。

Answer 1

更改data:"username="+username, 到data: {userName:username} 查询文档中的示例

$.ajax({
  type: "POST",
  url: "some.php",
  data: { name: "John", location: "Boston" }
})

http://api.jquery.com/jQuery.ajax/

Answer 2

错字：data:"username="+username应为data:"userName="+username

为避免此类错误，您也可以将javascript变量命名为userName;）

Answer 3

           $.ajax({
                    type:"post",
                    url:"CheckUserAction",
                    data:{"username": username },
                    success:function(data){  

                    //checking the code for username is present in database or not
                    }
           });

Answer 4

尝试

$.ajax({
  type:"post",
  url:"<s:url action='CheckUserAction'/>",
  data: { userName: username }
  success:function(data){                            
     //checking the code for username is present in database or not
  }
});

Answer 5

使用data: {"username":username},代替data:"username="+username,

Action类通过ajax调用从jsp页面获取null值

5 个答案: