code: function Valparams() {
    this.query = {};
    this.body = {};
    this.params = {};
    this.all = {};
    this.raw = { query: {}, body: {}, params: {} };
    this.err = null;
  }
docs: example use
  ---
  ```js
  // 可以全局定义
  const Valparams = require('path/to/Valparams[/index]');
  Valparams.locale('zh-cn');
  
  function list(req, res, next) {
  let validater = Valparams.setParams(req, {
  sysID : {alias:'sid',type: 'int', required: true, desc: '所属系统id'},
  page  : {type: 'int', required: false, defValue: 1,range:{min:0}, desc: '页码'},
  size  : {type: 'int', required: false, defValue: 30, desc: '页面大小'},
  offset: {type: 'int', required: false, defValue: 0, desc: '位移'}
  }, {
  choices : [{fields: ['sysID', 'page'], count: 1, force: false}],
  });
  if (validater.err && validater.err.length) {
  console.log(validater.err);
  }
  else {
  console.log(validater);
  //{ query: { page: 1, size: 30 },
  //  body: {},
  //  params: { sysID: 2 },
  //  all: { sysID: 2, page: 1, size: 30 },
  //  err: null }
  //  raw: { query: { page: 1, size: 30 },
  //         body: {},
  //         params: { sid: 2 },
  //       }
  //}
  //do something
  }
  }
  ```
  @type {Valparams}