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javascript JSON

骨灰级搬砖工 2023-02-15 阅读 140
DATAFORMATjsonJSON字符串HarmonyOS后端开发

CreateTime--2016年10月12日09:28:09

迁移时间--2017年5月16日10:19:12
Author:Marydon

二、javascript-JSON

本文主要讲的是在javascript中对JSON数据的操作，若想看java中如何对JSON对象进行操作，请见数据格式汇总2-java文章

　　（一）格式介绍

　　　　标准格式：

　　　　{"键":值,"键":值,"键":值}（值可以是数字，不加双引号；也可以是字符串，需加双引号；值也可以包含一个对象）

　　　　格式一：值存储的是多个对象

{"data":[{"TERM":"第一期","WANGWU":199,"LISI":229,"ZHAOLIU":233,"SANQI":234,"ZHANGSAN":233},{"TERM":"第二期","WANGWU":156,"LISI":186,"ZHAOLIU":179,"SANQI":206,"ZHANGSAN":234},{"TERM":"第三期","WANGWU":133,"LISI":161,"ZHAOLIU":246,"SANQI":185,"ZHANGSAN":240},{"TERM":"第四期","WANGWU":194,"LISI":126,"ZHAOLIU":190,"SANQI":207,"ZHANGSAN":229},{"TERM":"第五期","WANGWU":149,"LISI":166,"ZHAOLIU":209,"SANQI":174,"ZHANGSAN":197}],"code":0,"expMsg":"","msg":"操作成功"}

　　　　格式二：多个对象组成的数组

var row = '[{"TERM":"第一期","WANGWU":199,"LISI":229,"ZHAOLIU":233,"SANQI":234,"ZHANGSAN":233},{"TERM":"第二期","WANGWU":156,"LISI":186,"ZHAOLIU":179,"SANQI":206,"ZHANGSAN":234},{"TERM":"第三期","WANGWU":133,"LISI":161,"ZHAOLIU":246,"SANQI":185,"ZHANGSAN":240},{"TERM":"第四期","WANGWU":194,"LISI":126,"ZHAOLIU":190,"SANQI":207,"ZHANGSAN":229},{"TERM":"第五期","WANGWU":149,"LISI":166,"ZHAOLIU":209,"SANQI":174,"ZHANGSAN":197}]';

 （二）操作JSON

　　2.2.1 json赋值

在js中，[]表示数组；{}表示Json对象。

　　 　　以将map形式的字符串转成JSON对象为例举例

　　　　方式一：声明JSON对象

/**
 * 将map形式的字符串转成JSON对象
 * @param {string} mapStr
 * java-Map格式字符串
 */
function mapstringToJSON (mapStr) {
    // 1.去除字符串中所有的"
    mapStr = mapStr.replace(/"/g, "");
    // 2.去除掉"{}"
    mapStr = mapStr.substring(1, mapStr.length - 1);
    // 3.将map字符串用逗号拆分成数组
    var strs = mapStr.split(",");
    // 声明一个长度为2的数组
    var keyValue = new Array(2);
    // JSON-键    
    var key = "";
    // JSON-值
    var value = "";
    // 声明一个JSON对象
    var json = {};
    // 4.迭代map键值对
    $(strs).each(function(index, str) {
        keyValue = str.split("=");//按等号拆分成数组
        key = $.trim(keyValue[0]);
        value = $.trim(keyValue[1]);
        json[key] = value;// 动态值
        //json.key死值
    });
    
    return json;
}

var mapString = "{home=index, ForganizeCode=0, theme=window7, userAreaId=215, userManOrgs=10}";
var jsonObj = mapstringToJSON(mapString);
for (var key in jsonObj) {
    console.log(jsonObj[key]);
}

 　　　　注意：说说JSON对象中的"."与"[]"操作符的区别：

　　　　　　上面的key是动态的值，若用点操作，即json.key，其结果就是json对象中有且只有一个键：key，其他的键都没有加上；

点操作指定的是死键，[]操作既可用作表示死键，又可用作表示动态的键。

　　　　　　取值上：没太大区别。

　　　　方式二：字符串拼接

/**
 * 将map形式的字符串转成JSON对象
 * @param {string} mapStr
 * java-Map格式字符串
 */
function mapstringToJSON (mapStr) {
    // 1.去除字符串中所有的"
    mapStr = mapStr.replace(/"/g, "");
    // 2.去除掉"{}"
    mapStr = mapStr.substring(1, mapStr.length - 1);
    // 3.将map字符串用逗号拆分成数组
    var strs = mapStr.split(",");
    //JSON字符串
    var jsonStr = "";
    //声明一个长度为2的数组
    var keyValue = new Array(2);
    //JSON-键
    var key = "";
    //JSON-值
    var value = "";
    // 4.迭代map键值对
    $(strs).each(function(index, str) {
        keyValue = str.split("=");//按等号拆分成数组
        key = '"' + keyValue[0].trim() + '"';
        value = '"' + keyValue[1].trim() + '"';
        jsonStr += key + ":" + value + ",";//标准的JSON拼接格式
    });
    // 5.去除最后一个逗号并拼接"{}"
    jsonStr = "{" + jsonStr.substring(0, jsonStr.length - 1) + "}";
    // 6.json字符串转成JSON对象
    var json = eval（'(' + jsonStr + ')');
    return json;
}

var mapString = "{home=index, ForganizeCode=0, theme=window7, userAreaId=215, userManOrgs=10}";
var jsonObj = mapstringToJSON(mapString);
for (var key in jsonObj) {
    console.log(jsonObj[key]);
}

　　　　注意： 

 　　　　　　JSON字符串拼接原则：

1.键必须有双引号，不能是单引号；

2.键值对之间用逗号隔开；

3.键与值之间使用冒号。

 　　2.2.2 json格式取值

 　　UpdateTime--2016年10月25日11:37:09

　　　　2.2.2.1 json格式的字符串取值

　　　　数据格式

var jsonStr = '{"data":[{"FSTATE":"1","FRCODE":"410000","FZJM":"YFBJK","ROWNO":"1","FREMARK":"","FDEPTNAME":"预防保健科","FPLVCODE":"","FDEPTCODE":"01"},{"FSTATE":"1","FRCODE":"410000","FZJM":"QKYLK","ROWNO":"2","FREMARK":"","FDEPTNAME":"全科医疗科","FPLVCODE":"","FDEPTCODE":"02"},{"FSTATE":"1","FRCODE":"410000","FZJM":"NK","ROWNO":"3","FREMARK":"","FDEPTNAME":"内科","FPLVCODE":"","FDEPTCODE":"03"},{"FSTATE":"1","FRCODE":"410000","FZJM":"WK","ROWNO":"4","FREMARK":"","FDEPTNAME":"外科","FPLVCODE":"","FDEPTCODE":"04"},{"FSTATE":"1","FRCODE":"410000","FZJM":"FCK","ROWNO":"5","FREMARK":"","FDEPTNAME":"妇产科","FPLVCODE":"","FDEPTCODE":"05"}],"code":0,"msg":"操作成功！","expMsg":""}';

　　　　取值方法

//取对象
var jsonObj = eval（'('+jsonStr+')');
console.log(jsonObj.msg);
//取数组元素
var jsonObj = eval（'('+jsonStr+')');
var jsonObj2 = jsonObj.data;
for (var i = 0; i <jsonObj2.length; i++) {
　　console.log(jsonObj2[i].FDEPTNAME);
}

　　　　2.2.2.2 json格式取值

　　　　数据格式

var jsonStr = {"data":[{"FSTATE":"1","FRCODE":"410000","FZJM":"YFBJK","ROWNO":"1","FREMARK":"","FDEPTNAME":"预防保健科","FPLVCODE":"","FDEPTCODE":"01"},{"FSTATE":"1","FRCODE":"410000","FZJM":"QKYLK","ROWNO":"2","FREMARK":"","FDEPTNAME":"全科医疗科","FPLVCODE":"","FDEPTCODE":"02"},{"FSTATE":"1","FRCODE":"410000","FZJM":"NK","ROWNO":"3","FREMARK":"","FDEPTNAME":"内科","FPLVCODE":"","FDEPTCODE":"03"},{"FSTATE":"1","FRCODE":"410000","FZJM":"WK","ROWNO":"4","FREMARK":"","FDEPTNAME":"外科","FPLVCODE":"","FDEPTCODE":"04"},{"FSTATE":"1","FRCODE":"410000","FZJM":"FCK","ROWNO":"5","FREMARK":"","FDEPTNAME":"妇产科","FPLVCODE":"","FDEPTCODE":"05"}],"code":0,"msg":"操作成功！","expMsg":""};

　　　　取值方法　

//取对象
console.log(jsonStr.msg);
//取数组元素
var jsonObj2 = jsonStr.data;
for (var i = 0; i <jsonObj2.length; i++) {
    console.log(jsonObj2[i].FDEPTNAME);
}

　　　　2.2.2.3 json数组字符串格式的取值

　　　　数据格式　　

var jsonStr = '[{"FSTATE":"1","FRCODE":"410000","FZJM":"YFBJK","ROWNO":"1","FREMARK":"","FDEPTNAME":"预防保健科","FPLVCODE":"","FDEPTCODE":"01"},{"FSTATE":"1","FRCODE":"410000","FZJM":"QKYLK","ROWNO":"2","FREMARK":"","FDEPTNAME":"全科医疗科","FPLVCODE":"","FDEPTCODE":"02"},{"FSTATE":"1","FRCODE":"410000","FZJM":"NK","ROWNO":"3","FREMARK":"","FDEPTNAME":"内科","FPLVCODE":"","FDEPTCODE":"03"},{"FSTATE":"1","FRCODE":"410000","FZJM":"WK","ROWNO":"4","FREMARK":"","FDEPTNAME":"外科","FPLVCODE":"","FDEPTCODE":"04"},{"FSTATE":"1","FRCODE":"410000","FZJM":"FCK","ROWNO":"5","FREMARK":"","FDEPTNAME":"妇产科","FPLVCODE":"","FDEPTCODE":"05"}]';

　　　　取值方法

//取数组元素
var jsonObj = eval（'('+jsonStr+')');
for (var i = 0; i <jsonObj.length; i++) {
    console.log(jsonObj[i].FZJM);
}

　　　　2.2.2.4 json格式数组的取值

　　　　数据格式　　

var jsonObj = [{"FSTATE":"1","FRCODE":"410000","FZJM":"YFBJK","ROWNO":"1","FREMARK":"","FDEPTNAME":"预防保健科","FPLVCODE":"","FDEPTCODE":"01"},{"FSTATE":"1","FRCODE":"410000","FZJM":"QKYLK","ROWNO":"2","FREMARK":"","FDEPTNAME":"全科医疗科","FPLVCODE":"","FDEPTCODE":"02"},{"FSTATE":"1","FRCODE":"410000","FZJM":"NK","ROWNO":"3","FREMARK":"","FDEPTNAME":"内科","FPLVCODE":"","FDEPTCODE":"03"},{"FSTATE":"1","FRCODE":"410000","FZJM":"WK","ROWNO":"4","FREMARK":"","FDEPTNAME":"外科","FPLVCODE":"","FDEPTCODE":"04"},{"FSTATE":"1","FRCODE":"410000","FZJM":"FCK","ROWNO":"5","FREMARK":"","FDEPTNAME":"妇产科","FPLVCODE":"","FDEPTCODE":"05"}];

　　　　取值方法

//取数组元素for (var i = 0; i <jsonObj.length; i++) {
    console.log(jsonObj[i].FZJM);
}

　　　　2.2.2.5 判断JSON对象是否为空

jQuery.isEmptyObject(JSONObj)

　　（三）格式转换

　　　　3.3.1 json格式字符串与JSON对象的相互转化

　　　　　　3.3.1.1 json格式字符串转换成JSON对象　　

使用eval（'(' + 字符串 + ')')　

 　　　　　　　　json格式字符串转换成object类型的数组（为了便于理解，可以看成java中的JSONArray）

var jsonArray = eval（"("+row+")");
console.log(jsonArray);
//"[object Object],[object Object],[object Object],[object Object],[object Object]"

　　　　　　3.3.1.2 object类型（java中的JSONArray）转化成json字符串

使用JSON.stringify() 

var str = JSON.stringify(jsonArray);
console.log(str);
//"[{"TERM":"第一期","WANGWU":199,"LISI":229,"ZHAOLIU":233,"SANQI":234,"ZHANGSAN":233},{"TERM":"第二期","WANGWU":156,"LISI":186,"ZHAOLIU":179,"SANQI":206,"ZHANGSAN":234},{"TERM":"第三期","WANGWU":133,"LISI":161,"ZHAOLIU":246,"SANQI":185,"ZHANGSAN":240},{"TERM":"第四期","WANGWU":194,"LISI":126,"ZHAOLIU":190,"SANQI":207,"ZHANGSAN":229},{"TERM":"第五期","WANGWU":149,"LISI":166,"ZHAOLIU":209,"SANQI":174,"ZHANGSAN":197}]"

　　　　3.3.2 JSON对象转换成map字符串

/**
 * 将JSON对象转换成map形式的字符串
 * @param {Object} jsonObj 
 *     JSON对象
 */
function JSONToMapstring (jsonObj) {
    var mapString = "";
    //遍历JSON对象
    for (var item in jsonObj) {
        mapString += item + "=" + jsonObj[item] + ",";//标准的java—Map字符串拼接格式
    }
    //去除最后一个逗号并转成map形式字符串
    mapString = "{" + mapString.substring(0, mapString.length - 1) + "}";
    return mapString;
}

　　　　　　举例：

//接着上面的例子
var result = JSONToMapstring(jsonObj);
console.log(result);//"{home=index,ForganizeCode=0,theme=window7,userAreaId=215,userManOrgs=10}"

2023年1月31日15:23:23

JSON字符串转JSON对象

$.parseJSON(jsonstr); //jQuery.parseJSON(jsonstr))

JSON.parse(jsonstr);

eval('(' + jsonstr + ')');

JSON对象转JSON字符串

JSON.stringify(jsonobj);

 

写在最后

　　哪位大佬如若发现文章存在纰漏之处或需要补充更多内容，欢迎留言！！！

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