app.get('/one', function(req, res, next) {
  
  var sk = 'yoursk' // 创建应用的sk
    , address = '北京市'
    ;
  superagent.get('http://api.map.baidu.com/geocoder/v2/')
    .query({address: address})
    .query({output: 'json'})
    .query({ak: sk})
    .end(function(err, sres) {
      if (err) {
        console.log('err:', err);
        return;
      }
      res.send(sres.text);
    }) 
 })

{
  status: 0,
  result: {
  location: {
    lng: 116.39564503787867,
    lat: 39.92998577808024
  },
  precise: 0,
  confidence: 10,
  level: "城市"
}

app.get('/many', function(req, res, next) {
  var sk = 'yoursk'
    , addresses = ['北京市', '深圳市', '广州市', '普宁市']
    ;
  ep.after('getLocation', addresses.length, function(locations) {
    res.send(locations);
  })
  addresses.forEach(function(e, i) {
    superagent.get('http://api.map.baidu.com/geocoder/v2/')
      .query({address: e})
      .query({output: 'json'})
      .query({ak: sk})
      .end(function(err, sres) {
        ep.emit('getLocation', {address: e, res: sres.text})
      })  
  })
})

[
{
address: "北京市",
res: "{"status":0,"result":{"location":{"lng":116.39564503787867,"lat":39.92998577808024},"precise":0,"confidence":10,"level":"城市"}}"
},
{
address: "深圳市",
res: "{"status":0,"result":{"location":{"lng":114.0259736573215,"lat":22.546053546205248},"precise":0,"confidence":14,"level":"城市"}}"
},
{
address: "广州市",
res: "{"status":0,"result":{"location":{"lng":113.30764967515182,"lat":23.12004910207623},"precise":0,"confidence":12,"level":"城市"}}"
},
{
address: "普宁市",
res: "{"status":0,"result":{"location":{"lng":116.07816590835329,"lat":23.28895358314155},"precise":0,"confidence":14,"level":"区县"}}"
}
]

var xlsx = require('node-xlsx')
  , fs = require('fs')
  ;
var file_path = './query_result.xlsx';
var file_data = xlsx.parse(file_path);

file_data.forEach(function(sheet, index) {
  var sheetname = sheet.name // 表格名称
    , sheetdata = sheet.data // 表格的数据
    , sheethead = sheetdata[0] // 第一行一般为表头，但不是一定的
    , sheetbody = sheetdata.slice(1) // 真正的数据
    , file_path_towrite = './static/address.json'
    , file_data_json
    , cities_name = []
    ;
  // 将城市的数据写进去
  sheetbody.forEach(function(e, i) {
    cities_name.push('' + e[1] + ',' + e[2])
  })
  file_data_json = JSON.stringify({cities_name: cities_name});
  fs.writeFile(file_path_towrite, file_data_json, function(err) {
    if (err) 
      console.log('写入数据失败', err);
    else 
      console.log('写入文件成功');
  })
})

{"cities_name":["北京市,北京市","北京市,市辖区","天津市,天津市"]}

app.get('/', function(req, res, next) {
  var sk = 'yoursk'
    , addresses = []
    , file_path = './static/address.json'
    , file_path_towrite = './static/geocoder.json'
    , file_data
    ;

  fs.readFile(file_path, function(err, data) {
    if (err) {
      console.log('读取文件失败', err);
      return;
    }
    file_data = JSON.parse(data);
    addresses = file_data.cities_name;
    
    ep.after('getLocation', addresses.length, function(locations) {
      var file_data = {};
      locations.forEach(function(e, i) {
        file_data[e.address.split(',')[1]] = [e['location']['lng'], e['location']['lat']];
      })
      fs.writeFile(file_path_towrite, JSON.stringify(file_data), function(err) {
        if (err) 
          console.log('写入数据失败', err);
        else 
          console.log('获取数据并写入文件成功');
        res.send(file_data);
      })
    })
    addresses.forEach(function(e, i) {
      superagent.get('http://api.map.baidu.com/geocoder/v2/')
        .query({address: e.split(',').join(' ')})
        .query({city: e.split(',')[1]})
        .query({output: 'json'})
        .query({ak: sk})
        .end(function(err, sres) {
          var location
            , res_json
            ;
          res_json = JSON.parse(sres.text);
          if (res_json.status == 0) {
            location = res_json.result && res_json.result.location || '';
          } else {
            location = {"lng":0,"lat":0};
          }
          ep.emit('getLocation', {address: e, location: location})
        })
    })
  });
})