Spring Boot中BoardController获取userNo参数失败问题求助

错误核心原因 #

报错Required request parameter 'userNo' for method parameter type int is not present本质是：

• 前端未正确传递userNo参数，或传参方式与控制器@RequestParam的参数读取规则不匹配
• @RequestParam默认要求参数必填，若前端未传或传参位置错误，直接触发该异常

具体解决方案 #

1. 修正前端传参方式

如果前端通过URL参数或表单提交传递数据，必须保证参数名严格为userNo：

• URL示例：POST /increaseLike?boardNo=1&userNo=1001
• 表单提交示例：

  <form method="post" action="/increaseLike">
    <input type="hidden" name="boardNo" value="1">
    <input type="hidden" name="userNo" value="1001">
    <button type="submit">点赞/取消</button>
  </form>
  

• AJAX/axios请求（需用params传递，而非请求体）：

  axios.post('/increaseLike', null, {
    params: {
      boardNo: 1,
      userNo: 1001
    }
  })
  

2. 调整控制器参数注解（可选）

如果需要兼容未登录场景（允许userNo非必填），可以给@RequestParam添加required=false，并处理空值：

@PostMapping("/increaseLike")
@ResponseBody
public Map<String, Object> increaseLike(@RequestParam("boardNo") int boardNo, 
                                        @RequestParam(value = "userNo", required = false) Integer userNo) throws Exception {
    if (userNo == null) {
        Map<String, Object> errorResponse = new HashMap<>();
        errorResponse.put("code", 401);
        errorResponse.put("msg", "请先登录");
        return errorResponse;
    }
    boolean isLiked = likesService.toggleLike(boardNo, userNo);
    int likeCount = likesService.countLikesByBoard(boardNo);

    Map<String, Object> response = new HashMap<>();
    response.put("likeCount", likeCount);
    response.put("isLiked", isLiked); 
    return response;
}

3. 推荐：用DTO统一接收请求参数（更规范）

如果前端习惯用JSON格式传递请求体，建议创建DTO类，用@RequestBody接收，避免参数分散：

• 第一步：创建请求DTO

public class LikeToggleRequest {
    private int boardNo;
    private int userNo;

    // Getter、Setter
    public int getBoardNo() { return boardNo; }
    public void setBoardNo(int boardNo) { this.boardNo = boardNo; }
    public int getUserNo() { return userNo; }
    public void setUserNo(int userNo) { this.userNo = userNo; }
}

• 第二步：修改控制器方法

@PostMapping("/increaseLike")
@ResponseBody
public Map<String, Object> increaseLike(@RequestBody LikeToggleRequest request) throws Exception {
    boolean isLiked = likesService.toggleLike(request.getBoardNo(), request.getUserNo());
    int likeCount = likesService.countLikesByBoard(request.getBoardNo());

    Map<String, Object> response = new HashMap<>();
    response.put("likeCount", likeCount);
    response.put("isLiked", isLiked); 
    return response;
}

• 前端JSON请求示例：

axios.post('/increaseLike', {
    boardNo: 1,
    userNo: 1001
})

额外检查项 #

1. 确认Likes实体类存在对应构造函数：

public class Likes {
    private int boardNo;
    private int userNo;

    public Likes(int boardNo, int userNo) {
        this.boardNo = boardNo;
        this.userNo = userNo;
    }
    // 其他Getter、Setter
}

2. 补全MyBatis的deleteLikeXML配置：

<delete id="deleteLike" parameterType="moum.project.vo.Likes">
    DELETE FROM likes WHERE board_id = #{boardNo} AND user_id = #{userNo}
</delete>

内容的提问来源于stack exchange，提问作者codenoobie