java前后台之间传值的几种方式

自己写的代码太少，有时候前后台传值还写的不是很熟练，现在总结一下，加深下印象。

1.jquery的Ajax传值

----》前台到后台

期望功能：把前台用户输入的信息保存在数据库里。

前台jsp代码：

function saveUserInfo(){

  var params = {};//定义一个数组

  var userNO = jq("#userNO").val();//把前台页面上的值都赋予一个变量
  var userName = jq("#userName").val();
  var phoneNumber = jq("#phoneNumber").val();

  params["userNO"] = userNO ;//把这些变量都存在这个数组里
  params["userName"] = userName;
  params["phoneNumber"] = phoneNumber;

  jq.ajax({
        type : "post",
        url : "<%=basePath%>personalSetting/personalSettingSaveAll.do",//找到action里相应的方法
        data : params, //把数组的值赋给data，把上面的param改为data,这里就能直接去掉
        dataType : "text",//根据数据类型选择text、jason等
        success : function(data) { 
          alert(msg); //msg可以在后台Action配置，也可以在这里直接写提示信息
        },
        error : function(data) {
          alert("msg");
        }
       });
        } 
 }

后台Action代码：

@SuppressWarnings({ "unchecked", "unused", "rawtypes" })
@RequestMapping(value = "/personalSetting/personalSettingSaveAll.do", method = RequestMethod.POST)
public void saveAll(ModelMap model, HttpServletRequest request, HttpServletResponse response) throws Exception {
    response.setCharacterEncoding("UTF-8");
    HttpSession session = request.getSession();
    String userNO  = request.getParameter("userNO")+"";
    String userName = request.getParameter("userName")+"";
    String phoneNumber = request.getParameter("phoneNumber")+"";     
    PersonalSettingEntity pSE = new PersonalSettingEntity(); 
    if(!("".equals(userNO))||"".equals(userName )||"".equals(phoneNumber ))){ //如果都不为空  

        pSE.setUserNO(userNO);
        pSE.setUserName(userName);
        pSE.setPhoneNumber(phoneNumber);
        PersonSettingService.saveProcessSetting(pSE);
        msg = "保存成功";
    }else{
        msg = "填写不完整"; //可以在前台校验，这里为了举例子
    }
        response.getWriter().print(msg); //这里的msg是text数据，所以前台数据类型是text。
}

----》后台到前台

期望功能：把数据库里的用户信息显示到前台页面。

后台Action代码：

@SuppressWarnings({ "unchecked", "unused", "rawtypes" })
@RequestMapping(value = "/personalSetting/personalSettingInitAll.do", method = RequestMethod.POST)
public void qureyAll(ModelMap model, HttpServletRequest request, HttpServletResponse response) throws Exception {
    response.setCharacterEncoding("UTF-8");
    HttpSession session = request.getSession();
    String userId = request.getSession().getAttribute("currentUserId").toString();
    PersonalSettingEntity pSE = PersonSettingService.getPersonalSetting(Long.valueOf(userId));    
    response.getWriter().print(JSONArray.fromObject(pSE).toString());
}

前台jsp代码：

function get(){ 
  jq.ajax({
         type : "post",
         url : "<%=basePath%>personalSetting/personalSettingInitAll.do",
         dataType : "json",
         success :function (data) {
          var bean;
          jq.each(data,function(index){
          bean = data[index];
          jq("#userNO").attr("value",bean.userNO);
          jq("#userName").attr("value",bean.userName); 
          jq("#phoneNumber").attr("value",bean.phoneNumber);
           }                  
         },
         error :function (data){
            alert("系统出错！");
         }
   });  
 }