一：三种JSON格式

基本类型

{ 
    "student": "张三",
    "age": 18,
    "sex": true
}

数组类型

[
    { 
        "student": "张三",
        "age": 18,
        "sex": true
    },
    { 
        "student": "李四",
        "age": 19,
        "sex": false
    }
]

对象嵌套

{ 
    "student": "张三丰",
    "school": { 
    "class":"7班",
    "floor": "5层"
    },
    "students": [
        { 
            "student": "张三",
            "age": 18,
            "sex": true
        },
        { 
            "student": "李四",
            "age": 19,
            "sex": false
        }
    ]
}

二：利用alibaba.fastjson解析JSONObject、JSONArray

package com.test1;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
public class TestJsonArray { 
    public static void main(String[] args) { 
        // json字符串-简单对象型
        final String JSON_OBJ_STR = "{\"studentName\":\"lily\",\"studentAge\":12}";
        // json字符串-数组类型
        final String JSON_ARRAY_STR = "[{\"studentName\":\"lily\",\"studentAge\":12},{\"studentName\":\"lucy\",\"studentAge\":15}]";
        testJSONStrToJSONArray1(JSON_ARRAY_STR);
        testJSONStrToJSONObject(JSON_OBJ_STR);
    }
    /** * json字符串-数组类型与JSONArray之间的转换 */
    public static void testJSONStrToJSONArray1(String JSON_ARRAY_STR) { 
        JSONArray jsonArray = JSON.parseArray(JSON_ARRAY_STR);
        // JSONArray jsonArray1 =JSONArray.parseArray(JSON_ARRAY_STR);//因为JSONArray继承了JSON，所以这样也是可以的
        // 遍历方式1
        int size = jsonArray.size();
        for (int i = 0; i < size; i++) { 
            JSONObject jsonObject = jsonArray.getJSONObject(i);
            System.out.println(jsonObject.getString("studentName") + ":" + jsonObject.getInteger("studentAge"));
        }
        // 遍历方式2
        for (Object obj : jsonArray) { 
            JSONObject jsonObject = (JSONObject) obj;
            System.out.println(jsonObject.getString("studentName") + ":" + jsonObject.getInteger("studentAge"));
        }
    }
    /** * json字符串-简单对象型与JSONObject之间的转换 */
    public static void testJSONStrToJSONObject(String JSON_OBJ_STR) { 
         JSONObject jsonObject = JSON.parseObject(JSON_OBJ_STR);
         //JSONObject jsonObject1 = JSONObject.parseObject(JSON_OBJ_STR); //因为JSONObject继承了JSON，所以这样也是可以的
         System.out.println(jsonObject.getString("studentName") + ":" + jsonObject.getInteger("studentAge"));
    }
}

三：利用json.JSONObject解析JSONObject

package com.test1;
import org.json.JSONException;
import org.json.JSONObject;
public class TestJsonObject { 
     public static void main(String[] args) throws JSONException { 
            //记得转义
            String jsonStr="{\"studentName\":\"zhangsanfeng\",\"age\":18,\"school\":\"武当山大学\"}";
            JSONObject jsonObj = new JSONObject(jsonStr);
            int age = jsonObj.getInt("age");
            String school = jsonObj.optString("school");
            String studentName= (String) jsonObj.get("studentName");
            System.out.println(age);
            System.out.println(school);
            System.out.println(studentName);
        }
}

解析如下形式json数组

JSONObject json = new JSONObject(data);
            JSONArray rows = json.optJSONArray("IT_QUERY");
            for (int i = 0; i < rows.length(); i++) { 
                JSONObject row = rows.optJSONObject(i);
                //打印出WERKS字段值
                System.out.println(row.optString("WERKS"));
            }

四：将json数组后台解析分组，比如按照OrderNum

数据库中数据存储如下：

原始数据类型如下：

[
    { 
        ORDER_NUM=SD2520200522001,
        WERKS_DN=2050,
        POSNR=000010
    },
    { 
        ORDER_NUM=SD2520200610001,
        WERKS_DN=2050,
        POSNR=000010
    },
    { 
        ORDER_NUM=SD2520200610001,
        WERKS_DN=2050,
        POSNR=000010
    }
]

比如同一个单号，需要处理成如下类型json数据类型

{ 
    "SD2520200611004":[
        { 
            "ORDER_NUM":"SD2520200611004",
            "WERKS_DN":"2050",
            "POSNR":"000010"
        }],
    "SD2520200610001":[
        { 
            "ORDER_NUM":"SD2520200610001",
            "WERKS_DN":"2050",
            "POSNR":"000010"
        },
        { 
            "ORDER_NUM":"SD2520200610001",
            "WERKS_DN":"2050",
            "POSNR":"000010"
        }],
    "SD2520200522001":[
        { 
            "ORDER_NUM":"SD2520200522001",
            "WERKS_DN":"2050",
            "POSNR":"000010"
        }]
}

java代码如下：

public void run() { 
        // TODO Auto-generated method stub
        SD25TaskService sd25TaskService = applicationContext.getBean(SD25TaskService.class);
        try { 
            List list = sd25TaskService.getData();//从数据库中查询出数据
            JSONObject obj = new JSONObject();
            for (int i = 0; i < list.size(); i++) { 
                Map<String,Object> map = (Map<String, Object>) list.get(i);//遍历获取字段集合
                String orderNum = map.get("ORDER_NUM").toString();//按照ORDER_NUM进行区分
                if(!obj.containsKey(orderNum)) { //如果JSONObject不存在，则存按照<orderNum,List>形式存入JSONObject
                    List<Map<String,Object>> tempList = new ArrayList<>();//创建临时tempList作为list存储json数据
                    tempList.add(map);
                    obj.put(orderNum, tempList);
                }else { //如果存在，则先取出放入临时list，然后将当前的map存入临时tempList
                    List<Map<String,Object>> tempList = (List<Map<String, Object>>) obj.get(orderNum);
                    tempList.add(map);
                }
            }
            System.out.println(obj);
        } catch (Exception ex) { 
            LOG.error("仓管员收货自动过账提交BPM异常！", ex);
        }
    }

五：JS解析JSON对象

利用eval函数进行转换

var data= { 
    "name": "zhangsanfeng",
    "age": 118,
    "address": "beijing"
};
var json = eval('(' + data+ ')');
console.info(json.name);
console.info(json.age);
console.info(json.address);

六：解析JSON数组

6.1 解析方式1
拼接json数组，如{“IT_ITEM”:[{“VBELN”:“0080001496”}]}

var arry = [];
  var jsonArray = { };
  jsonArray.VBELN = "0080001496";
  arry.push(jsonArray);
  var inputTables = { };
  inputTables.IT_ITEM = arry;
  console.info(JSON.stringify(inputTables))

json数组格式如下
var data = “{“ET_INFO”:[{“VBELN”:“80001496”,“KBETR”:3.00,“POSNR”:“000010”,“ARKTX”:“受话器SDRP0615PJ02-04-056”,“WAERS”:“RMB”,“MEINS”:“PCS”,“LGMNG”:20.000,“WBSTA”:“A”,“MATNR”:“000000001400009338”,“NAME1”:“AMAZON”}]}”;

{ 
    "ET_INFO": [{ 
        "VBELN": "8000149",
        "KBETR": 3.00,
        "POSNR": "000010",
        "ARKTX": "受话器SD",
        "WAERS": "RMB",
        "MEINS": "PCS",
        "LGMNG": 20.0,
        "WBSTA": "A",
        "MATNR": "00000000140",
        "NAME1": "AMA"
    }]
}
var arrays = $.parseJSON(data.data).ET_INFO;
 for(var i=0 ;i<arrays.length;i++){ 
   var POSNR = arraus[i].POSNR;//交货项目
   var MATNR = arraus[i].MATNR;//物料号
   var ARKTX = arraus[i].ARKTX;//销售订单项目短文本
   var MEINS = arraus[i].MEINS;//基本计量单位
   var LGMNG = arraus[i].LGMNG;//以仓库保管单位级的实际交货数量
   var KBETR = arraus[i].KBETR;//价格
   var WAERS = arraus[i].WAERS;//货币码
   var WBSTA = arraus[i].WBSTA;//货物移动状态
   var NAME1 = arraus[i].NAME1;//名称
 }

6.2 解析方式2

var array = [{ 
            "name": "zhangsanfeng",
            "age": 118,
            "address": "beijing"
        }, { 
            "name": "lisiguang",
            "age": 119,
            "address": "shanghai"
        }, { 
            "name": "wangwuha",
            "age": 117,
            "address": "hangzhou"
        }];
for (var i in array ) { 
    console.info(array[i].name);
    console.info(array[i].age);
    console.info(array[i].address);
}

七：JSON与Map互相转换

package com.gzsolartech.bpmportal.util;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.directwebremoting.json.types.JsonObject;
import org.json.JSONArray;
import org.json.JSONObject;
public class JsonMapUtil { 
    public static Map convertJsonObjectToMap(JSONObject json){ 
        Map returnMap = new HashMap();
        Iterator<String> iterator = json.keys();
        while(iterator.hasNext()){ 
            String key = iterator.next();
            returnMap.put(key, json.opt(key));
        }
        return returnMap;
    }
    public static JSONObject convertMapToJsonObject(Map<String,Object> map){ 
        JSONObject json = new JSONObject();
        Set<String> set = map.keySet();
        Iterator<String> iterator = set.iterator();
        while(iterator.hasNext()){ 
            String key = iterator.next();
            json.put(key, map.get(key));
        }
        return json;
    }
    public static List<Map> convertJsonArrayToMap(JSONArray jsonArr){ 
        Map returnMap = new HashMap();
        List<Map> list = new ArrayList<>();
        for(int i=0;i<jsonArr.length();i++){ 
            JSONObject json = jsonArr.optJSONObject(i);
            Map map = convertJsonObjectToMap(json);
            list.add(map);
        }
        return list;
    }
}

参考文章
https://blog.csdn.net/dirft\_din/article/details/108325419
https://www.yiibai.com/html/json/2013/0906249.html