使用Java解析JSON數(shù)據(jù)并提取特定字段的實現(xiàn)步驟(以提取mailNo為例)

更新時間：2025年01月12日 14:08:35 作者：碼農阿豪@新空間代碼工作室

在現(xiàn)代軟件開發(fā)中,處理JSON數(shù)據(jù)是一項非常常見的任務,無論是從API接口獲取數(shù)據(jù),還是將數(shù)據(jù)存儲為JSON格式,解析和提取JSON中的特定字段都是開發(fā)人員需要掌握的基本技能,本文將以一個實際案例為例,詳細介紹如何使用Java解析JSON數(shù)據(jù)并提取其中的mailNo字段

1. 背景介紹

1.1 JSON簡介

JSON（JavaScript Object Notation）是一種輕量級的數(shù)據(jù)交換格式，易于人閱讀和編寫，同時也易于機器解析和生成。它基于JavaScript的一個子集，但獨立于語言，幾乎所有的編程語言都支持JSON格式的數(shù)據(jù)處理。

1.2 實際案例

假設我們有一個JSON數(shù)據(jù)，其中包含多個訂單信息，每個訂單都有一個唯一的mailNo字段。我們的目標是從這個JSON數(shù)據(jù)中提取出所有的mailNo字段，并將其存儲在一個列表中。

2. 準備工作

2.1 環(huán)境搭建

為了解析JSON數(shù)據(jù)，我們需要使用一個Java庫。在本文中，我們將使用Jackson庫，這是一個非常流行的JSON處理庫，功能強大且易于使用。

2.1.1 添加依賴

如果你使用Maven構建項目，可以在pom.xml中添加以下依賴：

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.13.3</version>
</dependency>

如果你使用Gradle構建項目，可以在build.gradle中添加以下依賴：

implementation 'com.fasterxml.jackson.core:jackson-databind:2.13.3'

2.2 JSON數(shù)據(jù)結構

以下是我們將要處理的JSON數(shù)據(jù)的示例：

{
  "msg": "操作成功!",
  "code": "ok",
  "result": {
    "records": [
      {
        "merchantId": 0,
        "organId": 0,
        "creatorId": 0,
        "creatorTruename": "",
        "creatorUsername": "",
        "organName": "",
        "merchantTruename": "",
        "merchantUsername": "",
        "consigneeName": "突然的自我",
        "consigneePhone": "153****7763",
        "consigneeTelPhone": "*******7763",
        "consigneeCompany": "",
        "consigneeProvinceId": 0,
        "consigneeProvince": "四川省",
        "consigneeCityId": 0,
        "consigneeCity": "綿陽市",
        "consigneeDistrictId": 0,
        "consigneeDistrict": "涪城區(qū)",
        "consigneeAddress": "四川省****靚妍美妝",
        "sendProvinceId": 0,
        "sendProvince": "貴州省",
        "sendCityId": 0,
        "sendCity": "遵義市",
        "sendDistrictId": 0,
        "sendDistrict": "紅花崗區(qū)",
        "senderName": "夜郎酒業(yè)",
        "senderCompany": "",
        "senderPhone": "155****7773",
        "senderTelPhone": "*******7773",
        "senderDetailAddress": "貴州省****中轉倉庫",
        "mailNo": "SF3150804745040",
        "subWaybillNoList": [],
        "waybillStatus": 50,
        "printSerialNumber": "",
        "printStatus": 0,
        "printNumber": 0,
        "orderValueAddedVo": null,
        "addedServiceCodes": [],
        "callFlag": "",
        "consignment": "夜郎醬宏圖純糧食大曲坤沙酒醬香型白酒禮盒裝53度500ml",
        "consignmentNumber": 2,
        "parcelWeight": "2.0",
        "parcelWeightUnit": "2.0",
        "parcelQuantity": 1,
        "meterageWeightQty": "2.0",
        "realWeightQty": "2.0",
        "orderNo": "6938567762089547327|2kBWWcmNUwX2SZ",
        "originalOrderNo": "",
        "signBackNo": "",
        "remark": "",
        "orderCreateTime": "2025-01-10 15:29:41",
        "waybillCreateTime": "2025-01-10 15:29:41",
        "printTime": null,
        "isShowExcludeFile": 0,
        "freight": "1000.0",
        "referenceCost": "",
        "waybillNums": 1,
        "status": "",
        "exceptionFlag": 0,
        "promiseTime": "",
        "receiveTime": "2025-01-10 16:16:55",
        "signTime": "2025-01-11 14:13:40",
        "latestRouteInfo": "您的快件已由本人簽收，如有疑問請電聯(lián)快遞員【楊發(fā)斌，電話：13330891935】。您的體驗對于我們至關重要，如果您對我們的服務有任何的想法和建議，請隨時聯(lián)系我們，我們一定用心傾聽，全力改進，不辜負您的信任與支持。",
        "latestOpCode": "80",
        "expressProductId": 0,
        "expressProductCode": "B1",
        "expressProductName": "電商標快",
        "expressPayMethod": 1,
        "expressPayMethodName": "寄付月結",
        "monthlyCard": "052***6969",
        "orderType": 1,
        "customField1": "",
        "customField2": "",
        "customField3": "",
        "amount": "",
        "collectionAmount": "",
        "collectingNumber": "",
        "oldCollectingMoney": "",
        "exceptionCode": "",
        "orderId": 0,
        "waybillId": 0,
        "isUpdateWaybill": 0,
        "mergeOrderType": 2,
        "isDraft": null,
        "failCause": "",
        "orderCrossBorderGoodsVoList": [
          {
            "productCode": "",
            "productName": "夜郎醬宏圖純糧食大曲坤沙酒醬香型白酒禮盒裝53度500ml",
            "price": 0.0,
            "currencyCode": "",
            "currencyName": "",
            "unit": "",
            "productNumber": 2.0,
            "orderType": 0,
            "countryOfOrigin": ""
          }
        ],
        "gangAoTaiExtVo": null,
        "swFlag": 0,
        "sendStatus": 1,
        "sendStatusName": "獲取成功",
        "expressCompanyMerchantId": 0,
        "totalLength": 41.0,
        "totalHeight": 1.0,
        "totalWidth": 1.0,
        "addedValueServiceInfo": {
          "insuredType": 0,
          "insuredPrice": null,
          "collectingMoney": null,
          "collectingMonthlyCard": "",
          "signBackName": [],
          "signBackNo": "",
          "signBackWaybillStatus": 0,
          "signBackOrderType": [],
          "signBackRouteList": [],
          "isSignBack": 0,
          "signBackRemark": "",
          "signBackNum": 0,
          "thirdSignBack": 0,
          "thirdConsigneeName": "",
          "thirdConsigneePhone": "",
          "thirdConsigneeTel": "",
          "thirdConsigneeProvince": "",
          "thirdConsigneeCity": "",
          "thirdConsigneeArea": "",
          "thirdConsigneeAddress": "",
          "thirdConsigneeCompany": "",
          "takePhotoBack": [],
          "takePhotoNum": 0,
          "takePhotoBackRemark": "",
          "timingSendInformType": 0,
          "timingSendInformDate": "",
          "timingSendInformTime": "",
          "electronicBack": 0,
          "secretKeyAuthentication": "",
          "secretKeyAuthenticationValue": "",
          "woodenPackage": 0,
          "woodenPackageInfo": "",
          "readySend": 0,
          "woodenRemovalNum": 0,
          "packagingService": "",
          "packagingMaterialVos": [],
          "overweightService": 0,
          "timingInsured": 0,
          "freshService": 0,
          "homeDeliveryExt": [],
          "installationType": 0,
          "installationContent": [],
          "selfPickup": 0,
          "exhibitionService": 0,
          "exhibitionExitService": 0,
          "addedServiceCodes": [],
          "customDeliveryTime": ""
        },
        "signBackInfo": "",
        "signBackNum": "",
        "pickupAppointTime": "",
        "consValueCurrencyCode": "",
        "exportDeclarationMethod": "",
        "customsBatchs": "",
        "taxAccount": "",
        "taxPaymentType": "",
        "custReferenceNo": "",
        "isSignBack": 0,
        "signBackRemark": "",
        "cancelTime": null
      },
      {
        "merchantId": 0,
        "organId": 0,
        "creatorId": 0,
        "creatorTruename": "",
        "creatorUsername": "",
        "organName": "",
        "merchantTruename": "",
        "merchantUsername": "",
        "consigneeName": "**",
        "consigneePhone": "157*********2541",
        "consigneeTelPhone": "************2541",
        "consigneeCompany": "",
        "consigneeProvinceId": 0,
        "consigneeProvince": "貴州省",
        "consigneeCityId": 0,
        "consigneeCity": "貴陽市",
        "consigneeDistrictId": 0,
        "consigneeDistrict": "修文縣",
        "consigneeAddress": "貴州省****獸霸鞋店",
        "sendProvinceId": 0,
        "sendProvince": "貴州省",
        "sendCityId": 0,
        "sendCity": "遵義市",
        "sendDistrictId": 0,
        "sendDistrict": "紅花崗區(qū)",
        "senderName": "小包",
        "senderCompany": "",
        "senderPhone": "155****1949",
        "senderTelPhone": "*******1949",
        "senderDetailAddress": "貴州省****菜鳥驛站",
        "mailNo": "SF3150809345059",
        "subWaybillNoList": [],
        "waybillStatus": 50,
        "printSerialNumber": "",
        "printStatus": 0,
        "printNumber": 0,
        "orderValueAddedVo": null,
        "addedServiceCodes": [],
        "callFlag": "",
        "consignment": "2024男鞋男士舒適時尚百搭黑色41",
        "consignmentNumber": 1,
        "parcelWeight": "2.5",
        "parcelWeightUnit": "2.5",
        "parcelQuantity": 1,
        "meterageWeightQty": "2.5",
        "realWeightQty": "2.5",
        "orderNo": "6938535195456968508|6780cc24dd560100",
        "originalOrderNo": "",
        "signBackNo": "",
        "remark": "驢孤品42碼",
        "orderCreateTime": "2025-01-10 15:28:59",
        "waybillCreateTime": "2025-01-10 15:28:59",
        "printTime": null,
        "isShowExcludeFile": 0,
        "freight": "1000.0",
        "referenceCost": "",
        "waybillNums": 1,
        "status": "",
        "exceptionFlag": 0,
        "promiseTime": "",
        "receiveTime": "2025-01-10 18:42:03",
        "signTime": "2025-01-11 09:40:32",
        "latestRouteInfo": "您的快件已由本人簽收，如有疑問請電聯(lián)快遞員【王昭發(fā)，電話：18143512989】。您的體驗對于我們至關重要，如果您對我們的服務有任何的想法和建議，請隨時聯(lián)系我們，我們一定用心傾聽，全力改進，不辜負您的信任與支持。",
        "latestOpCode": "80",
        "expressProductId": 0,
        "expressProductCode": "B1",
        "expressProductName": "電商標快",
        "expressPayMethod": 1,
        "expressPayMethodName": "寄付月結",
        "monthlyCard": "052***6969",
        "orderType": 1,
        "customField1": "",
        "customField2": "",
        "customField3": "",
        "amount": "",
        "collectionAmount": "",
        "collectingNumber": "",
        "oldCollectingMoney": "",
        "exceptionCode": "",
        "orderId": 0,
        "waybillId": 0,
        "isUpdateWaybill": 0,
        "mergeOrderType": 2,
        "isDraft": null,
        "failCause": "",
        "orderCrossBorderGoodsVoList": [
          {
            "productCode": "",
            "productName": "2024男鞋男士舒適時尚百搭黑色41",
            "price": 0.0,
            "currencyCode": "",
            "currencyName": "",
            "unit": "",
            "productNumber": 1.0,
            "orderType": 0,
            "countryOfOrigin": ""
          }
        ],
        "gangAoTaiExtVo": null,
        "swFlag": 0,
        "sendStatus": 1,
        "sendStatusName": "獲取成功",
        "expressCompanyMerchantId": 0,
        "totalLength": 0.0,
        "totalHeight": 0.0,
        "totalWidth": 0.0,
        "addedValueServiceInfo": {
          "insuredType": 0,
          "insuredPrice": null,
          "collectingMoney": null,
          "collectingMonthlyCard": "",
          "signBackName": [],
          "signBackNo": "",
          "signBackWaybillStatus": 0,
          "signBackOrderType": [],
          "signBackRouteList": [],
          "isSignBack": 0,
          "signBackRemark": "",
          "signBackNum": 0,
          "thirdSignBack": 0,
          "thirdConsigneeName": "",
          "thirdConsigneePhone": "",
          "thirdConsigneeTel": "",
          "thirdConsigneeProvince": "",
          "thirdConsigneeCity": "",
          "thirdConsigneeArea": "",
          "thirdConsigneeAddress": "",
          "thirdConsigneeCompany": "",
          "takePhotoBack": [],
          "takePhotoNum": 0,
          "takePhotoBackRemark": "",
          "timingSendInformType": 0,
          "timingSendInformDate": "",
          "timingSendInformTime": "",
          "electronicBack": 0,
          "secretKeyAuthentication": "",
          "secretKeyAuthenticationValue": "",
          "woodenPackage": 0,
          "woodenPackageInfo": "",
          "readySend": 0,
          "woodenRemovalNum": 0,
          "packagingService": "",
          "packagingMaterialVos": [],
          "overweightService": 0,
          "timingInsured": 0,
          "freshService": 0,
          "homeDeliveryExt": [],
          "installationType": 0,
          "installationContent": [],
          "selfPickup": 0,
          "exhibitionService": 0,
          "exhibitionExitService": 0,
          "addedServiceCodes": [],
          "customDeliveryTime": ""
        },
        "signBackInfo": "",
        "signBackNum": "",
        "pickupAppointTime": "",
        "consValueCurrencyCode": "",
        "exportDeclarationMethod": "",
        "customsBatchs": "",
        "taxAccount": "",
        "taxPaymentType": "",
        "custReferenceNo": "",
        "isSignBack": 0,
        "signBackRemark": "",
        "cancelTime": null
      }
    ],
    "total": 5167,
    "size": 1000,
    "current": 1,
    "orders": [],
    "searchCount": true,
    "pages": 6
  }
}

3. 實現(xiàn)步驟

3.1 創(chuàng)建Java類

我們將創(chuàng)建一個名為MailNoExtractor的Java類，用于解析JSON數(shù)據(jù)并提取mailNo字段。

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class MailNoExtractor {

    public static List<String> extractMailNos(String json) throws IOException {
        ObjectMapper objectMapper = new ObjectMapper();
        JsonNode rootNode = objectMapper.readTree(json);
        JsonNode recordsNode = rootNode.path("result").path("records");

        List<String> mailNos = new ArrayList<>();

        for (JsonNode record : recordsNode) {
            String mailNo = record.path("mailNo").asText();
            mailNos.add(mailNo);
        }

        return mailNos;
    }

    public static void main(String[] args) {
        String json = "{\"msg\":\"操作成功!\",\"code\":\"ok\",\"result\":{\"records\":[{\"merchantId\":0,\"organId\":0,\"creatorId\":0,\"creatorTruename\":\"\",\"creatorUsername\":\"\",\"organName\":\"\",\"merchantTruename\":\"\",\"merchantUsername\":\"\",\"consigneeName\":\"突然的自我\",\"consigneePhone\":\"153****7763\",\"consigneeTelPhone\":\"*******7763\",\"consigneeCompany\":\"\",\"consigneeProvinceId\":0,\"consigneeProvince\":\"四川省\",\"consigneeCityId\":0,\"consigneeCity\":\"綿陽市\(zhòng)",\"consigneeDistrictId\":0,\"consigneeDistrict\":\"涪城區(qū)\",\"consigneeAddress\":\"四川省****靚妍美妝\",\"sendProvinceId\":0,\"sendProvince\":\"貴州省\",\"sendCityId\":0,\"sendCity\":\"遵義市\(zhòng)",\"sendDistrictId\":0,\"sendDistrict\":\"紅花崗區(qū)\",\"senderName\":\"夜郎酒業(yè)\",\"senderCompany\":\"\",\"senderPhone\":\"155****7773\",\"senderTelPhone\":\"*******7773\",\"senderDetailAddress\":\"貴州省****中轉倉庫\",\"mailNo\":\"SF3150804745040\",\"subWaybillNoList\":[],\"waybillStatus\":50,\"printSerialNumber\":\"\",\"printStatus\":0,\"printNumber\":0,\"orderValueAddedVo\":null,\"addedServiceCodes\":[],\"callFlag\":\"\",\"consignment\":\"夜郎醬宏圖純糧食大曲坤沙酒醬香型白酒禮盒裝53度500ml\",\"consignmentNumber\":2,\"parcelWeight\":\"2.0\",\"parcelWeightUnit\":\"2.0\",\"parcelQuantity\":1,\"meterageWeightQty\":\"2.0\",\"realWeightQty\":\"2.0\",\"orderNo\":\"6938567762089547327|2kBWWcmNUwX2SZ\",\"originalOrderNo\":\"\",\"signBackNo\":\"\",\"remark\":\"\",\"orderCreateTime\":\"2025-01-10 15:29:41\",\"waybillCreateTime\":\"2025-01-10 15:29:41\",\"printTime\":null,\"isShowExcludeFile\":0,\"freight\":\"1000.0\",\"referenceCost\":\"\",\"waybillNums\":1,\"status\":\"\",\"exceptionFlag\":0,\"promiseTime\":\"\",\"receiveTime\":\"2025-01-10 16:16:55\",\"signTime\":\"2025-01-11 14:13:40\",\"latestRouteInfo\":\"您的快件已由本人簽收，如有疑問請電聯(lián)快遞員【楊發(fā)斌，電話：13330891935】。您的體驗對于我們至關重要，如果您對我們的服務有任何的想法和建議，請隨時聯(lián)系我們，我們一定用心傾聽，全力改進，不辜負您的信任與支持。\",\"latestOpCode\":\"80\",\"expressProductId\":0,\"expressProductCode\":\"B1\",\"expressProductName\":\"電商標快\",\"expressPayMethod\":1,\"expressPayMethodName\":\"寄付月結\",\"monthlyCard\":\"052***6969\",\"orderType\":1,\"customField1\":\"\",\"customField2\":\"\",\"customField3\":\"\",\"amount\":\"\",\"collectionAmount\":\"\",\"collectingNumber\":\"\",\"oldCollectingMoney\":\"\",\"exceptionCode\":\"\",\"orderId\":0,\"waybillId\":0,\"isUpdateWaybill\":0,\"mergeOrderType\":2,\"isDraft\":null,\"failCause\":\"\",\"orderCrossBorderGoodsVoList\":[{\"productCode\":\"\",\"productName\":\"夜郎醬宏圖純糧食大曲坤沙酒醬香型白酒禮盒裝53度500ml\",\"price\":0.0,\"currencyCode\":\"\",\"currencyName\":\"\",\"unit\":\"\",\"productNumber\":2.0,\"orderType\":0,\"countryOfOrigin\":\"\"}],\"gangAoTaiExtVo\":null,\"swFlag\":0,\"sendStatus\":1,\"sendStatusName\":\"獲取成功\",\"expressCompanyMerchantId\":0,\"totalLength\":41.0,\"totalHeight\":1.0,\"totalWidth\":1.0,\"addedValueServiceInfo\":{\"insuredType\":0,\"insuredPrice\":null,\"collectingMoney\":null,\"collectingMonthlyCard\":\"\",\"signBackName\":[],\"signBackNo\":\"\",\"signBackWaybillStatus\":0,\"signBackOrderType\":[],\"signBackRouteList\":[],\"isSignBack\":0,\"signBackRemark\":\"\",\"signBackNum\":0,\"thirdSignBack\":0,\"thirdConsigneeName\":\"\",\"thirdConsigneePhone\":\"\",\"thirdConsigneeTel\":\"\",\"thirdConsigneeProvince\":\"\",\"thirdConsigneeCity\":\"\",\"thirdConsigneeArea\":\"\",\"thirdConsigneeAddress\":\"\",\"thirdConsigneeCompany\":\"\",\"takePhotoBack\":[],\"takePhotoNum\":0,\"takePhotoBackRemark\":\"\",\"timingSendInformType\":0,\"timingSendInformDate\":\"\",\"timingSendInformTime\":\"\",\"electronicBack\":0,\"secretKeyAuthentication\":\"\",\"secretKeyAuthenticationValue\":\"\",\"woodenPackage\":0,\"woodenPackageInfo\":\"\",\"readySend\":0,\"woodenRemovalNum\":0,\"packagingService\":\"\",\"packagingMaterialVos\":[],\"overweightService\":0,\"timingInsured\":0,\"freshService\":0,\"homeDeliveryExt\":[],\"installationType\":0,\"installationContent\":[],\"selfPickup\":0,\"exhibitionService\":0,\"exhibitionExitService\":0,\"addedServiceCodes\":[],\"customDeliveryTime\":\"\"},\"signBackInfo\":\"\",\"signBackNum\":\"\",\"pickupAppointTime\":\"\",\"consValueCurrencyCode\":\"\",\"exportDeclarationMethod\":\"\",\"customsBatchs\":\"\",\"taxAccount\":\"\",\"taxPaymentType\":\"\",\"custReferenceNo\":\"\",\"isSignBack\":0,\"signBackRemark\":\"\",\"cancelTime\":null},{\"merchantId\":0,\"organId\":0,\"creatorId\":0,\"creatorTruename\":\"\",\"creatorUsername\":\"\",\"organName\":\"\",\"merchantTruename\":\"\",\"merchantUsername\":\"\",\"consigneeName\":\"**\",\"consigneePhone\":\"157*********2541\",\"consigneeTelPhone\":\"************2541\",\"consigneeCompany\":\"\",\"consigneeProvinceId\":0,\"consigneeProvince\":\"貴州省\",\"consigneeCityId\":0,\"consigneeCity\":\"貴陽市\(zhòng)",\"consigneeDistrictId\":0,\"consigneeDistrict\":\"修文縣\",\"consigneeAddress\":\"貴州省****獸霸鞋店\",\"sendProvinceId\":0,\"sendProvince\":\"貴州省\",\"sendCityId\":0,\"sendCity\":\"遵義市\(zhòng)",\"sendDistrictId\":0,\"sendDistrict\":\"紅花崗區(qū)\",\"senderName\":\"小包\",\"senderCompany\":\"\",\"senderPhone\":\"155****1949\",\"senderTelPhone\":\"*******1949\",\"senderDetailAddress\":\"貴州省****菜鳥驛站\",\"mailNo\":\"SF3150809345059\",\"subWaybillNoList\":[],\"waybillStatus\":50,\"printSerialNumber\":\"\",\"printStatus\":0,\"printNumber\":0,\"orderValueAddedVo\":null,\"addedServiceCodes\":[],\"callFlag\":\"\",\"consignment\":\"2024男鞋男士舒適時尚百搭黑色41\",\"consignmentNumber\":1,\"parcelWeight\":\"2.5\",\"parcelWeightUnit\":\"2.5\",\"parcelQuantity\":1,\"meterageWeightQty\":\"2.5\",\"realWeightQty\":\"2.5\",\"orderNo\":\"6938535195456968508|6780cc24dd560100\",\"originalOrderNo\":\"\",\"signBackNo\":\"\",\"remark\":\"驢孤品42碼\",\"orderCreateTime\":\"2025-01-10 15:28:59\",\"waybillCreateTime\":\"2025-01-10 15:28:59\",\"printTime\":null,\"isShowExcludeFile\":0,\"freight\":\"1000.0\",\"referenceCost\":\"\",\"waybillNums\":1,\"status\":\"\",\"exceptionFlag\":0,\"promiseTime\":\"\",\"receiveTime\":\"2025-01-10 18:42:03\",\"signTime\":\"2025-01-11 09:40:32\",\"latestRouteInfo\":\"您的快件已由本人簽收，如有疑問請電聯(lián)快遞員【王昭發(fā)，電話：18143512989】。您的體驗對于我們至關重要，如果您對我們的服務有任何的想法和建議，請隨時聯(lián)系我們，我們一定用心傾聽，全力改進，不辜負您的信任與支持。\",\"latestOpCode\":\"80\",\"expressProductId\":0,\"expressProductCode\":\"B1\",\"expressProductName\":\"電商標快\",\"expressPayMethod\":1,\"expressPayMethodName\":\"寄付月結\",\"monthlyCard\":\"052***6969\",\"orderType\":1,\"customField1\":\"\",\"customField2\":\"\",\"customField3\":\"\",\"amount\":\"\",\"collectionAmount\":\"\",\"collectingNumber\":\"\",\"oldCollectingMoney\":\"\",\"exceptionCode\":\"\",\"orderId\":0,\"waybillId\":0,\"isUpdateWaybill\":0,\"mergeOrderType\":2,\"isDraft\":null,\"failCause\":\"\",\"orderCrossBorderGoodsVoList\":[{\"productCode\":\"\",\"productName\":\"2024男鞋男士舒適時尚百搭黑色41\",\"price\":0.0,\"currencyCode\":\"\",\"currencyName\":\"\",\"unit\":\"\",\"productNumber\":1.0,\"orderType\":0,\"countryOfOrigin\":\"\"}],\"gangAoTaiExtVo\":null,\"swFlag\":0,\"sendStatus\":1,\"sendStatusName\":\"獲取成功\",\"expressCompanyMerchantId\":0,\"totalLength\":0.0,\"totalHeight\":0.0,\"totalWidth\":0.0,\"addedValueServiceInfo\":{\"insuredType\":0,\"insuredPrice\":null,\"collectingMoney\":null,\"collectingMonthlyCard\":\"\",\"signBackName\":[],\"signBackNo\":\"\",\"signBackWaybillStatus\":0,\"signBackOrderType\":[],\"signBackRouteList\":[],\"isSignBack\":0,\"signBackRemark\":\"\",\"signBackNum\":0,\"thirdSignBack\":0,\"thirdConsigneeName\":\"\",\"thirdConsigneePhone\":\"\",\"thirdConsigneeTel\":\"\",\"thirdConsigneeProvince\":\"\",\"thirdConsigneeCity\":\"\",\"thirdConsigneeArea\":\"\",\"thirdConsigneeAddress\":\"\",\"thirdConsigneeCompany\":\"\",\"takePhotoBack\":[],\"takePhotoNum\":0,\"takePhotoBackRemark\":\"\",\"timingSendInformType\":0,\"timingSendInformDate\":\"\",\"timingSendInformTime\":\"\",\"electronicBack\":0,\"secretKeyAuthentication\":\"\",\"secretKeyAuthenticationValue\":\"\",\"woodenPackage\":0,\"woodenPackageInfo\":\"\",\"readySend\":0,\"woodenRemovalNum\":0,\"packagingService\":\"\",\"packagingMaterialVos\":[],\"overweightService\":0,\"timingInsured\":0,\"freshService\":0,\"homeDeliveryExt\":[],\"installationType\":0,\"installationContent\":[],\"selfPickup\":0,\"exhibitionService\":0,\"exhibitionExitService\":0,\"addedServiceCodes\":[],\"customDeliveryTime\":\"\"},\"signBackInfo\":\"\",\"signBackNum\":\"\",\"pickupAppointTime\":\"\",\"consValueCurrencyCode\":\"\",\"exportDeclarationMethod\":\"\",\"customsBatchs\":\"\",\"taxAccount\":\"\",\"taxPaymentType\":\"\",\"custReferenceNo\":\"\",\"isSignBack\":0,\"signBackRemark\":\"\",\"cancelTime\":null}],\"total\":5167,\"size\":1000,\"current\":1,\"orders\":[],\"searchCount\":true,\"pages\":6}}";

        try {
            List<String> mailNos = extractMailNos(json);
            for (String mailNo : mailNos) {
                System.out.println(mailNo);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

3.2 代碼解析

3.2.1 extractMailNos 方法

功能：該方法接收一個JSON字符串作為輸入，使用Jackson庫解析JSON，并提取出所有mailNo字段的值，返回一個包含所有mailNo的列表。
步驟：
1. 使用ObjectMapper將JSON字符串解析為JsonNode對象。
2. 通過path方法獲取result節(jié)點下的records數(shù)組。
3. 遍歷records數(shù)組，提取每個記錄中的mailNo字段，并將其添加到列表中。