实例解析java + jQuery + json工作过程(登录)

$.ajax({
        url : url,
        data : {
                id : chkValue
        },
        cache : false,
        dataType : "json",
        success : function(result){
                alert(result);
        }
);

用户名：
<input id="loginName" name="loginName" size="20" type="text" />
 
密码：
<input id="password" name="password" size="20" type="password" />

/**
 * 设置表单验证规则
 */
function regFormValidator() {
        $.formValidator.initConfig({formid:"loginForm"});
        $("#loginName").formValidator({
                onshow : "请输入用户名",
                onfocus : "用户名至少2个字,最多4个字"
        }).inputValidator({
                min : 1,
                onerror : "你输入的用户名非法,请确认"
        });
 
        $("#password").formValidator({
                onshow : "请输入密码"
        }).inputValidator({
                min : 6,
                onerror : "密码在6位以上，请确认"
        });
}
 
$(function() {
        // 注册表单验证插件
        regFormValidator();
 
        $('#submit').click(function(){
                // 验证输入的用户名、密码是否正确
                var valid = jQuery.formValidator.pageIsValid('1');
                if (valid) {
                        $(this).attr('value', '正在登录……').attr('disabled', true);
                } else {
                        return;
                }
 
                // 发送请求
                $.ajax({
                        url     : 'login.do',
                        data    : { loginName:$('#loginName').val(), password: $('#password').val() },
                        success : function(result){
                                // 根据result返回信息判断是否登录成功
                                if(result && result == 'success') {
                                        window.location.href = 'index.jsp';
                                } else {
                                        alert('登录失败，用户名或密码错误，请重试！');
                                }
                        }
                });
 
        });
});

/**
 * 读取请求参数转换JSONObject对象
 *
 * @param request HttpServletRequest 对象
 * @return json格式的String对象
 * @throws Exception
 */
@SuppressWarnings("unchecked")
protected JSONObject readJson(HttpServletRequest request) throws Exception {
        JSONObject jsonObject = new JSONObject();
        try {
                Map parameterMap = request.getParameterMap();
                // 通过循环遍历的方式获得key和value并set到JSONObject中
                Iterator paIter = parameterMap.keySet().iterator();
                while (paIter.hasNext()) {
                        String key = paIter.next().toString();
                        String[] values = (String[])parameterMap.get(key);
                        jsonObject.accumulate(key, values[0]);
                }
                log.debug("从客户端获得json=" + jsonObject.toString());
        } catch (Exception e) {
                log.error("获取json数据出错，错误信息如下：nt" + e.getMessage());
                e.printStackTrace();
                throw e;
        }
        return jsonObject;
}

public ActionForward login(ActionMapping mapping, ActionForm actionForm,
             HttpServletRequest request,HttpServletResponse response) throws Exception {
        JSONObject jsonObject = readJson(request);
        String name = jsonObject.getString("loginName");
        String pass = jsonObject.getString("password");
        try {
                int loginFlag = userManager.validLogin(name, pass);
                if (loginFlag == UserManager.LOGIN_SUCCESS) {
                        User user = userManager.getUserByNameAndPass(name, pass);
                        UserUtil.saveUser2Session(user, request);
                        log.info("用户<" + user.getUserName()
                              + ",ip=" + request.getRemoteAddr() + ">登录系统");
                        print(response, RESBONSE_SUCCESS);
                } else if (loginFlag == UserManager.LOGIN_FAIL) {
                        print(response, RESBONSE_ERROR);
                }
        } catch (Exception e) {
                e.printStackTrace();
        }
        return null;
}

protected void print(HttpServletResponse response, String info) throws IOException {
        try {
                response.getWriter().print(info);
        } catch (IOException e) {
                e.printStackTrace();
                throw e;
        }
}