小东西

<script type="text/javascript">
$(document).ready(function(){
$('button').click(function(){
var usernmae = $('#username').val();
var password = $('#password').val();
var url='<%=path%>/login';
var dataj={'loginName':usernmae,'password':password};
$.ajax({
type:'POST',
url:url,
contentType:'application/json;charset=utf-8',
dataType:'json',
data:JSON.stringify(dataj),
success:function(data){
alert(data);
},
error:function(){

}
})

});

});
</script>

===============================================================================

@RequestMapping("/login")
public Object loginPost( @RequestBody User loginUser) throws Exception {
    logger.info("login ");
    if (StringUtils.isEmpty(loginUser.getLoginName())) {
        throw new Exception("user name is null");
    }
    if (StringUtils.isEmpty(loginUser.getPassword())) {
        throw new Exception("pwd is null");
    }
    Subject user = SecurityUtils.getSubject();
    UsernamePasswordToken token = new UsernamePasswordToken(loginUser.getLoginName(), DigestUtils.md5Hex(loginUser.getPassword()).toCharArray());
    token.setRememberMe(true);
    try {
        user.login(token);
    } catch (UnknownAccountException e) {
        throw new RuntimeException("the count not exit", e);
    } catch (DisabledAccountException e) {
        throw new RuntimeException("account can't use", e);
    } catch (IncorrectCredentialsException e) {
        throw new RuntimeException("pwd is wrong", e);
    } catch (Throwable e) {
        throw new RuntimeException("other exception", e);
    }
    return null;
}