var oJSON = [
    {businessNum:2,merchantBusinessId:456}，
    {businessNum:1,merchantBusinessId:154}，
    {businessNum:3,merchantBusinessId:336}，
    {businessNum:5,merchantBusinessId:108}
];

制一个函数 fn(json); 出来如一下这种形式（字符串）：

"[{\"amount\":\"1\",\"merbusinessId\":\"92\"},{\"amount\":\"1\",\"merbusinessId\":\"94\"},{\"amount\":\"1\",\"merbusinessId\":\"107\"}]"

原属数据：

oJSON = [{
  brandName: "",
  businessCode: "0b489a6d-9844-4f0e-a977-d5bb983d36e5",
  businessName: "内饰清洁",
  businessNum: 2,
  id: null,
  merchantBusinessId: 95,
  merchantId: 34,
  price: 300,
  privilegePrice: 0,
  shoppingCarDetialsId: 659,
  totalCurrentPrice: null,
  totalNum: null,
  totalPrice: null,
  userId: 439,
 }, {

  brandName: "",
  businessCode: "0b489a6d-9844-4f0e-a977-d5bb983d36e5",
  businessName: "内饰清洁",
  businessNum: 1,
  id: null,
  merchantBusinessId: 108,
  merchantId: 34,
  price: 300,
  privilegePrice: 0,
  shoppingCarDetialsId: 659,
  totalCurrentPrice: null,
  totalNum: null,
  totalPrice: null,
  userId: 439,
 }, {

  brandName: "",
  businessCode: "0b489a6d-9844-4f0e-a977-d5bb983d36e5",
  businessName: "内饰清洁",
  businessNum: 5,
  id: null,
  merchantBusinessId: 666,
  merchantId: 34,
  price: 300,
  privilegePrice: 0,
  shoppingCarDetialsId: 659,
  totalCurrentPrice: null,
  totalNum: null,
  totalPrice: null,
  userId: 439,


 }];  //取 businessNum 和   merchantBusinessId 字段