SSM框架前后端信息交互实现流程详解

<script language="JavaScript">
  ......
      function SaveUserFollowUser(){
      var login_user_id = ${login_user_id}    //登录者（发起者）编号
      var user_id = ${user.user_id};       //接受者用户编号

      $.ajax({
        url:"<%=path%>/UserRelation/SaveUserFollowUser",
        type:"POST",
        async: false,
        contentType:"application/json;charset=UTF-8",
        dataType:'json',

        data:JSON.stringify({"from_user_id":login_user_id,"to_user_id":user_id}), //JSON对象转为字符串
        success:function(data){
          /* 可在后端增加判断发起者和接受者用户是否是同一用户的判断 */
          if (data == true) {
            alert("关注成功");
          } else {
            alert("您已经关注该用户，不可重复关注")
          }
        }
      });
    }
</script>

......
      <button class="btn btn-success" style="width: 100px" onclick="SaveUserFollowUser()">关注用户</button>
......

/**
 * 表现层 用户关系相关 (关注用户、被用户关注、关注问题、赞同回答)
 */
@Controller
@RequestMapping("/UserRelation")
public class UserRelationController {

  ......

   /**
   * 新增某用户关注某用户
   * @param map
   * @return
   */
  @RequestMapping(value = "/SaveUserFollowUser",method = {RequestMethod.POST})
  public @ResponseBody Boolean SaveUserFollowUser(@RequestBody Map<String,String> map) {

    //关注发出者编号
    Integer from_user_id = Integer.parseInt(map.get("from_user_id"));
    //关注接受者编号
    Integer to_user_id = Integer.parseInt(map.get("to_user_id"));
    //是否新增成功
    //该项可以增加发起者用户和接受者用户是否是同一用户的判断，即比较from_user_id与to_user_id是否相等，如果相等则关注失败
    //通过返回Integer类型而非Boolean类型的做判断 本程序并未增加这项判断
    Boolean flag = userRelationService.saveUserFollowUser(from_user_id,to_user_id);
    return flag;
  }
  ......
}

/**
 * 表现层 用户
 */
@Controller
@RequestMapping(value = "/User")
public class UserController {

  ......

  /**
   * 进入个人信息页面
   * @param httpSession
   * @param model
   * @return
   */
  @RequestMapping(value = "/DisplayMyInfo")
  public String DisplayMyInfo(HttpSession httpSession, Model model) {
    Integer user_id = (Integer) httpSession.getAttribute("login_user_id");  //登录者个人编号
    User user = userService.findUserById(user_id); //登录者个人信息

    model.addAttribute("user",user);       //将登录者个人信息返回给前端
    return "User/myInfo";
  }
  ......
}

......
      <div class="col-md-6 col-md-offset-5" style="text-align: left;">
        <h2>用户名:${user.user_name}</h2>
        <h2>用户昵称:${user.user_nickname}</h2>
        <h2>用户性别:${user.user_sex}</h2>
        <h2>用户邮箱:${user.user_email}</h2>
        <h2>用户密码:${user.user_password}</h2>
      </div>
......