通过实例解析json与jsonp原理及使用方法

示列1：{} 用来描述一组“不同类型的无序键值对集合”
    var person = {
      "Name": "Bob",
      "Age": 32,
      "Company": "IBM",
      "Engineer": true
    }
  示列2：[] 用来描述一组“相同类型的有序数据集合”
    var members = [
      {
        "Name": "Bob",
        "Age": 32,
        "Company": "IBM",
        "Engineer": true
      },
      {
        "Name": "John",
        "Age": 20,
        "Company": "Oracle",
        "Engineer": false
      },
      {
        "Name": "Henry",
        "Age": 45,
        "Company": "Microsoft",
        "Engineer": false
      }
    ]
    //读取其中John的公司名称
    var johnsCompany = members[1].Company;
  
  示列3：{}中包含的[]使用
    var conference = {
      "Conference": "Future Marketing",
      "Date": "2012-6-1",
      "Address": "Beijing",
      "Members":
      [
        {
          "Name": "Bob",
          "Age": 32,
          "Company": "IBM",
          "Engineer": true
        },
        {
          "Name": "John",
          "Age": 20,
          "Company": "Oracle",
          "Engineer": false
        },
        {
          "Name": "Henry",
          "Age": 45,
          "Company": "Microsoft",
          "Engineer": false
        }
      ]
    }
  
    // 读取参会者Henry是否工程师
    var henryIsAnEngineer = conference.Members[2].Engineer;

function ajaxFun(){
      var strUrl="http://www.b.com/demo/json.txt";
       $.ajax({
        type:"get",
        url:strUrl,
        dataType: 'jsonp',
        jsonp: "callback",//传递给请求处理程序或页面的，用以获得jsonp回调函数名的参数名(一般默认为:callback)
        jsonpCallback: "flightHandler",//自定义的jsonp回调函数名称，默认为jQuery自动生成的随机函数名，也可以写"?"，jQuery会自动为你处理数据
        success: function(data){
          alert('您查到的信息：票价' + data.price + '元，余-票' + data.tickets + '张。');
        },
        error: function(XMLHttpRequest,textStatus,errorThrown){
          alert("error");
          // 状态码
          console.log(XMLHttpRequest.status);
          // 状态
          console.log(XMLHttpRequest.readyState);
          // 错误信息  
          console.log(textStatus);
         }
      });
    }

public String jsonReturn(HttpServletResponse response, String callback, Map<String, Object> jsonMap) {
    if (org.apache.commons.lang.StringUtils.isEmpty(callback)) {
      return appAjaxJson(response, getJson(jsonMap));
    }
    return appAjaxJson(response, callback + "(" + getJson(jsonMap) + ")");
  }

  public String appAjaxJson(HttpServletResponse response, String jsonString) {
    return appAjax(response, jsonString, "text/html");
  }

  public String appAjax(HttpServletResponse response, String content, String type) {
    try {
      response.setContentType(type + ";charset=UTF-8");
      response.setHeader("Access-Control-Allow-Origin", "*");//表示支持跨域请求
      // 如果IE浏览器则设置头信息如下
      if ("IE".equals(type)) {
        response.addHeader("XDomainRequestAllowed", "1");
      }
      response.setHeader("Pragma", "No-cache");
      response.setHeader("Cache-Control", "no-cache");
      response.setDateHeader("Expires", 0);
      response.getWriter().write(content);
      response.getWriter().flush();
    } catch (IOException e) {
      this.logException(e);
    }
    return null;
  }

示列1：
  let arr = [1,2,3];
  JSON.stringify(arr);//"[1,2,3]"
  typeof JSON.stringify(arr);//"string"

  示例2：
  //判断数组是否包含某对象
  let data = [
    {name:'echo'},
    {name:'听风是风'},
    {name:'天子笑'},
    ],
    val = {name:'天子笑'};
  JSON.stringify(data).indexOf(JSON.stringify(val)) !== -1;//true

  //判断两数组/对象是否相等
  let a = [1,2,3],
    b = [1,2,3];
  JSON.stringify(a) === JSON.stringify(b);//true