Jquery Node.js+；快速POST请求返回未定义的

我在后端有Node.js+express，并试图解析简单POST请求的主体。 但结果是在服务器控制台上获得“未定义”

我在StackOverflow上尝试了很多我在这里找到的选项-什么都不管用。 （版本中似乎不需要正文解析器，但即使包含正文解析器也不起作用）

下面是我的代码示例：

Node.js配置（快速版本：express@4.17.1)：

var express = require('express');
var app = express();
const path = require('path');
const PORT = process.env.PORT || 5000;

let ejs = require('ejs');

app.use(express.json());
app.use(express.text());

/* ... Some code ... */

  .use(express.static(path.join(__dirname, 'public')))
  .set('view engine', 'ejs')
  .post('/gaapi-post', function(req, res){
    console.log('***** Post fields: ******');
    console.log(req.body);
  })  

// jQuery JSON
jQuery.ajax({
    url: '/gaapi-post',
    type: 'POST',
    contentType: 'application/json',
    data: { "x": "5", "y": "6" }, // Valid JSOP should have " instead of '
});

// jQuery simple text
$.post( "/gaapi-post", 'test');


// Curl in console
curl -H "Content-Type: application/json" -X POST -d '{"username":"xyz","password":"xyz"}' http://localhost:5000/gaapi-post

Node.js路由：

var express = require('express');
var app = express();
const path = require('path');
const PORT = process.env.PORT || 5000;

let ejs = require('ejs');

app.use(express.json());
app.use(express.text());

/* ... Some code ... */

  .use(express.static(path.join(__dirname, 'public')))
  .set('view engine', 'ejs')
  .post('/gaapi-post', function(req, res){
    console.log('***** Post fields: ******');
    console.log(req.body);
  })  

// jQuery JSON
jQuery.ajax({
    url: '/gaapi-post',
    type: 'POST',
    contentType: 'application/json',
    data: { "x": "5", "y": "6" }, // Valid JSOP should have " instead of '
});

// jQuery simple text
$.post( "/gaapi-post", 'test');


// Curl in console
curl -H "Content-Type: application/json" -X POST -d '{"username":"xyz","password":"xyz"}' http://localhost:5000/gaapi-post

POST请求示例：

var express = require('express');
var app = express();
const path = require('path');
const PORT = process.env.PORT || 5000;

let ejs = require('ejs');

app.use(express.json());
app.use(express.text());

/* ... Some code ... */

  .use(express.static(path.join(__dirname, 'public')))
  .set('view engine', 'ejs')
  .post('/gaapi-post', function(req, res){
    console.log('***** Post fields: ******');
    console.log(req.body);
  })  

// jQuery JSON
jQuery.ajax({
    url: '/gaapi-post',
    type: 'POST',
    contentType: 'application/json',
    data: { "x": "5", "y": "6" }, // Valid JSOP should have " instead of '
});

// jQuery simple text
$.post( "/gaapi-post", 'test');


// Curl in console
curl -H "Content-Type: application/json" -X POST -d '{"username":"xyz","password":"xyz"}' http://localhost:5000/gaapi-post

上述代码中可能会有哪些更改或改进

---

提前谢谢

默认情况下，req.body是未定义的，并且在使用body解析器和multer等body解析中间件时填充。因此，您需要使用其中一个中间件。Express（4.x）将主体解析器中间件与核心框架分离。因此，如果需要主体解析器，则需要单独安装：

npm install body-parser --save

以下是主体解析器的代码示例：

const app = require('express')();
const bodyParser = require('body-parser');

// for parsing application/json
app.use(bodyParser.json());

// for parsing application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: true }));