text: var express    = require('express')
  var app = express()
  
  
  app.get("/err/*",function (req,rsp) {
      rsp.send((10/0));
  });
  
  // 单个使用
  app.use('/err/single/**',function(err, req, res, next) {
      console.log("err/single")
      console.error(err.stack);
      res.status(500).send(`err/single ${err.message}`);
  });
  
  // err 中间件需要放在最后边
  app.use('/err/many/**',function(err, req, res, next) {
      console.error(err.stack);
      next(err);
  });
  
  app.use('/err/many/**',function(err, req, res, next) {
      res.status(500).send(`err/many ${err.message}`);
  });
  
  let port = 3000;
  app.listen(port);
  console.log(`start with ${port}`)