javascript - Angular 2 中出现 404 错误，即使后端 Nodejs url 在浏览器中输入时有效并显示来自 Oracle 的数据

Question

我正在尝试在我的 Angular 前端中显示数据，该前端是针对链接到我的 Node 后端的 Oracle DB 调用的。目前，如果我转到 phsyiscal API 链接，我将看到数据，并将显示在我的后端 console.log 中。

我在这里错过了一些简单的事情吗？我是新手，如果这很容易，请提前道歉。

Angular 页面组件

import { Component, OnInit } from '@angular/core';
import { Observable } from 'rxjs';
import { DBService, Group} from '../db.service';
import { HttpClient } from '@angular/common/http';
import { NgIf } from '@angular/common/src/directives/ng_if';
import { element } from 'protractor';
import { ActivatedRoute } from '@angular/router';
import { Router } from '@angular/router';


@Component({
  selector: 'app-flow',
  templateUrl: './flow.component.html',
  styleUrls: ['../css.css']
})
export class FlowComponent implements OnInit {

  groups: Group[];

  constructor(
    private auth: AuthenticationService,
    private dbService: DBService,
    private route: ActivatedRoute,
    private router: Router
  ) {}



  ngOnInit() {

    this.dbService.getGroup2().subscribe(groups => this.groups = groups);
  }

}

数据库服务代码

getGroup2(): Observable<Group[]> {
 const url = 'http://localhost:4200/api/' + 'employees';
 const data = ({
 });
 return this._http.post(url, data)
 .pipe(
  map((res) => {
     console.log(res);
    return <Group[]> res;
  })
 );
 }

后端

服务/router.js

const express = require('express');
const router = new express.Router();
const employees = require('../controllers/employees.js');

router.route('/employees')
  .get(employees.get);

module.exports = router;

服务/database.js

const oracledb = require('oracledb');
const dbConfig = require('../config/database.js');

async function initialize() {
  const pool = await oracledb.createPool(dbConfig.hrPool);
}

module.exports.initialize = initialize;

// close the function

async function close() {
    await oracledb.getPool().close();
  }
  
  module.exports.close = close;

// simple executre function

function simpleExecute(statement, binds = [], opts = {}) {
    return new Promise(async (resolve, reject) => {
      let conn;
  
      opts.outFormat = oracledb.OBJECT;
      opts.autoCommit = true;
  
      try {
        conn = await oracledb.getConnection();
  
        const result = await conn.execute(statement, binds, opts);
  
        resolve(result);
      } catch (err) {
        reject(err);
      } finally {
        if (conn) { // conn assignment worked, need to close
          try {
            await conn.close();
          } catch (err) {
            console.log(err);
          }
        }
      }
    });
  }
  
  module.exports.simpleExecute = simpleExecute;

controllers/employees.js

const employees = require('../db_apis/employees.js');

async function get(req, res, next) {
  try {
    const context = {};

  //  context.id = parseInt(req.params.id, 10);

    const rows = await employees.find(11);

    if (req.params.id) {
      if (rows.length === 1) {
        res.status(200).json(rows[0]);
      } else {
        res.status(404).end();
      }
    } else {
      res.status(200).json(rows);
    }
  } catch (err) {
    next(err);
  }
}

module.exports.get = get;

db_apis/employees.js

const database = require('../services/database.js');

const baseQuery = 
 `SELECT * FROM DB.EMPLOYEES`;

async function find(context) {
 // let query = baseQuery;
//  const binds = {};

//   if (context.id) {
//   binds.employee_id = context.id;

//    query += `\nwhere employee_id = :employee_id`;
//  }

  const result = await database.simpleExecute(baseQuery);
  
  console.log(result.rows);
  return result.rows;

}

module.exports.find = find;

Answer 1

您有router.route('/employees').get(employees.get);，但在您的服务中您正在执行this._http.post(url, data)

您应该执行 get 请求 this._http.get(url)...。