PostgreSQL插入API报JSON解析错误，请求协助排查

错误信息 #

Unexpected token , in JSON at position 197
at JSON.parse ()
at parse (C:\Users\hp\empServers\node_modules\body-parser\lib\types\json.js:89:19)
at C:\Users\hp\empServers\node_modules\body-parser\lib\read.js:128:18
at AsyncResource.runInAsyncScope (node:async_hooks:203:9)

控制器代码 #

app.post("/svr/employees", function (req, res, next) {
  console.log("Request Body:", req.body);
  let { empCode, name, department, designation, salary, gender } = req.body;
  if (
    !empCode ||
    !name ||
    !department ||
    !designation ||
    salary === undefined ||
    !gender
  ) {
    res.status(400).send("Invalid data. Please provide all required fields.");
    return;
  }
  const insertQuery =
    "INSERT INTO employee (empcode, name, department, designation, salary, gender) VALUES ($1, $2, $3, $4, $5, $6)";
  const values = [empCode, name, department, designation, salary, gender];
  client.query(insertQuery, values, function (err, result) {
    if (err) {
      console.error("Error while inserting data:", err);
      res.status(500).send("An error occurred while inserting data.");
    } else {
      console.log(result);
      res.send(`${result.rowCount} insertion Successful`);
    }
  });
});

请求JSON体 #

{
  "empcode": 1129,
  "name": "hafsdmbdfsd",
  "department": "Technology",
  "designation": "Mansdfsdfager",
  "salary": 657567,
  "gender": "Male"
},

问题原因与修复方案 #

1. 直接导致JSON解析失败的原因 #

请求JSON末尾多了一个冗余的逗号（,），违反JSON语法规范，body-parser无法解析格式错误的JSON。

修复：移除末尾逗号，修正后的JSON如下：

{
  "empcode": 1129,
  "name": "hafsdmbdfsd",
  "department": "Technology",
  "designation": "Mansdfsdfager",
  "salary": 657567,
  "gender": "Male"
}

2. 隐藏的参数匹配问题 #

控制器中解构的变量是empCode（驼峰命名），但JSON字段是empcode（全小写），会导致empCode值为undefined，触发参数校验错误。

修复：统一命名规则，二选一即可：

• 方案一：修改JSON字段为empCode；
• 方案二：修改控制器中的解构与校验逻辑：

  let { empcode, name, department, designation, salary, gender } = req.body;
  if (
    !empcode ||
    !name ||
    !department ||
    !designation ||
    salary === undefined ||
    !gender
  ) {
    // 原有校验逻辑不变
  }
  

3. 测试验证 #

发送修正后的请求，body-parser可正常解析JSON，参数校验与数据库插入逻辑将正常执行。

内容的提问来源于stack exchange，提问作者roht_938