1. First, introduce the jQuery package in the jsp file in the foreground, and write the path of the file and the settings of the text box
<script src="./js/jquery-1.7.min.js"></script>
<!-- Employee ID--> <div class="am-form-group"> <label for="user-name" class="am-u-sm-3 am-form-label">员工编号</label> <div class="am-u-sm-9"> <input type="text" name="no" style="width: 300px; float: left;" id="no" placeholder="Please enter employee number"><span style="color: #F00; float: left; margin-top: 5px;">* </span> <span id="vno" style="padding-top: 10px;"></span> </div> </div> <!-- Department-->
2. In the jsp file, write the code of jquery
<script>
//Use ajax to determine whether the employee's number is registered
$(function(){
$('#no').blur(function(){//Mouse move away event
var no = $('#no').val();//Get the value in the text box
/* alert(no); */
// part of the path
var path = '<%=request.getContextPath()%>';
$.ajax({
type : "post",//How to submit
url : path + "/employee",//full path
async : false,
data : {//The passed value and the method to jump to the servlet file
"no" : no,
"action" : "check"
},
//If successful, determine whether the number is available
success : function(data) {//The sql statement in the Dao file has already queried how many numbers are entered at the front desk, if 1 is unavailable, if 0 is available
if (data > 0) {
$('#vno').text('The username ID is repeated and cannot be used');
} else {//Determine whether the text box is empty
if (no == "" || no == null) {
$('#vno').text('Please enter the employee number');
} else {
$('#vno').text('Congratulations! This user ID can be registered');
}
}
},
error : function() {
alert("failure")
}
});
})
})
</script>
3. Write the method in the servlet file
else if (action != null && action.equals("check")) {
/**
* Determine whether the number is registered
*/
//define a print
PrintWriter print = response.getWriter();
EmployeeDao employeedao = new EmployeeDao();
//Get the number in the foreground text box
String no = request.getParameter("no");
try {//Pass the data returned in the Dao file to shu
int shu = employeedao.bianhao(no);
// Pass the information to the data in the foreground
print.print(shu);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace ();
}
print.flush();
print.close();
}
4. Write the method called in the servlet method in the Dao file
/**
* Determine whether the employee number has been registered
*/
public int bianhao(String no) throws SQLException {
//Query the number of numbers written in the foreground in the database
String sql = "select count(EM_NO) from task_employee where EM_NO=?";
Connection conn = null;
PreparedStatement stmt = null;
//define a count
int count = 0;
conn = getConn();
stmt = conn.prepareStatement(sql);
stmt.setString(1, no);
ResultSet rs = stmt.executeQuery();
//Get the number entered in the text box and store the number in the database into count
if (rs.next()) {
count = rs.getInt(1);
}
//Return the number of query IDs in the database
return count;
}
final style
