students%5B0%5D表示：students[0]

%5B为左中括号[

%5D为右中括号]

这样就明白了

var qs = require('qs');
var obj = {
  name:'Tom',
  description:'hello',
  hobbies:['basketball','swimming']
};
//stringify查询字符串
var str = qs.stringify(obj);
console.log(str);
//运行结果：name=Tom&descript=hello&hobbies%5B0%5D=basketball&hobbies%5B1%5D=swimming