五.学生管理系统

1.数据库

这里以 mysql 为例，启动 mysql,使用 node 编写查询语句

2.后端接口

package.json

{
  "name": "eg",
  "version": "0.0.0",
  "private": true,
  "scripts": {
    "start": "node ./bin/www"
  },
  "dependencies": {
    "cookie-parser": "~1.4.3",
    "debug": "~2.6.9",
    "express": "^4.16.4",
    "http-errors": "~1.6.2",
    "jade": "~1.11.0",
    "morgan": "~1.9.0",
    "mysql": "^2.16.0"
  }
}

/routes/add.js

var express = require("express")
var router = express.Router()
const { sql_query, sql_add } = require("../public/mysql")
var querystring = require("querystring")
router.all("*", function (req, res, next) {
  res.header("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS")
  res.header("Access-Control-Allow-Origin", "http://localhost:8080")
  res.header("Content-Type", "application/json;charset=utf-8")
  next()
})
/* GET home page. */
router.post("/", function (req, res, next) {
  let data = req.body
  sql_add(data.s_name, data.s_english, data.s_math, (r) => {
    sql_query((r) => {
      let result = { code: 200 }
      result.data = r
      res.send(result)
    })
  })
})

module.exports = router

/routes/delete.js

var express = require("express")
var router = express.Router()
const { sql_query, sql_delete } = require("../public/mysql")
var querystring = require("querystring")

router.all("*", function (req, res, next) {
  res.header("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS")
  res.header("Access-Control-Allow-Origin", "http://localhost:8080")
  res.header("Content-Type", "application/json;charset=utf-8")
  next()
})
/* GET users listing. */
router.delete("/", function (req, res, next) {
  let data = ""
  req.on("data", (chunk) => {
    data += chunk
  })
  req.on("end", () => {
    data = querystring.parse(data.toString())
    sql_delete(data.id, (r) => {
      sql_query((r) => {
        let result = { code: 200 }
        result.data = r
        res.send(result)
      })
    })
  })
})

module.exports = router

/routes/query.js

var express = require("express")
var router = express.Router()
const { sql_query } = require("../public/mysql")

router.all("*", function (req, res, next) {
  res.header("Access-Control-Allow-Origin", "http://localhost:8080")
  res.header("Content-Type", "application/json;charset=utf-8")
  next()
})

router.get("/", function (req, res, next) {
  sql_query((r) => {
    let result = { code: 200 }
    result.data = r
    res.send(result)
  })
})

module.exports = router

/routes/updata.js

var express = require("express")
var router = express.Router()
const { sql_update, sql_query } = require("../public/mysql")
var querystring = require("querystring")

router.all("*", function (req, res, next) {
  res.header("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS")
  res.header("Access-Control-Allow-Origin", "http://localhost:8080")
  res.header("Content-Type", "application/json;charset=utf-8")
  next()
})

/* GET users listing. */
router.put("/", function (req, res, next) {
  let data = req.body
  console.log(data)
  sql_update(data.id, data.s_name, data.s_english, data.s_math, (r) => {
    sql_query((r) => {
      let result = { code: 200 }
      result.data = r
      res.send(result)
    })
  })
})

module.exports = router

app.js

var createError = require("http-errors")
var express = require("express")
var router = express.Router()

//设置请求头
router.all("*", function (req, res, next) {
  // res.header("Access-Content-Allow-Origin", "*");
  // res.header("Access-Control-Allow-Headers", "X-Requested-Width");
  // res.header("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");
  // res.header("X-Powered-By", "3.2.1");
  res.header("Access-Control-Allow-Origin", "http://localhost:8080")
  res.header("Content-Type", "application/json;charset=utf-8")
  next()
})
//路径解析
var path = require("path")
//这就是一个解析cookie的工具，通过req.cookies可以取到传过来的cookie，并把他们转成对象
var cookieParser = require("cookie-parser")
//在控制台中，显示req请求的信息
var logger = require("morgan")
//node中间件，用于处理JSON,Raw，text和url编码的数据
var bodyParser = require("body-parser")

//路由信息（接口地址），存放在routes的根目录
var addRouter = require("./routes/add")
var deleteRouter = require("./routes/delete")
var updataRouter = require("./routes/updata")
var queryRouter = require("./routes/query")

var app = express()

// view engine setup
app.set("views", path.join(__dirname, "views"))
app.set("view engine", "jade")

//载入中间件
app.use(logger("dev"))
app.use(express.json())
app.use(express.urlencoded({ extended: false }))
app.use(cookieParser())
app.use(express.static(path.join(__dirname, "public")))
app.use(bodyParser.json())
app.use(bodyParser.urlencoded({ extended: false }))

//配置路由（自定义路径，上面设置的接口地址）
app.use("/add", addRouter)
app.use("/delete", deleteRouter)
app.use("/updata", updataRouter)
app.use("/query", queryRouter)

// 错误处理
app.use(function (req, res, next) {
  next(createError(404))
})

// error handler
app.use(function (err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message
  res.locals.error = req.app.get("env") === "development" ? err : {}

  // render the error page
  res.status(err.status || 500)
  res.render("error")
})

module.exports = app