One requirement now is to asynchronously verify that the username exists. The techniques used are jQuery asynchronous validation and struts2 (the same goes for springMVC, which is just a controller).

Form:

<input class="width150" maxlength="32" type="text" id="dept_name" name="dept.dept_name"
value="${dept.dept_name}" onchange="tocheckname()"/>

Js code:

function tocheckname()
{
var deptName= $("#dept_name").val();
$.ajax({
type:"POST",
cache:false,
url : "${rootPath}/dept/checkdeptname.htm",
dataType : "text",
data:{"dept.id":"${dept.id}","dept.dept_name":deptName},
async:false,
success : function(data){
if(0<parseInt(data)){
alert(" This section already exists ");
$("#dept_name").attr("value","");
$("#dept_name").focus();
}
}
});
}

Background code:

public String checkdeptname() throws Exception {
if (UtilAPI.isNull(dept)) {
dept = new Dept();
}
int count = this.deptService.checkdeptname(dept.getId(), dept.getDept_name()); //If there is a return 1, there is no return 0
try {
response.getOutputStream().print(count);
}
catch (IOException e) {
e.printStackTrace();
}
return Action.NONE;
}