快捷導(dǎo)航

在Java中解析JSON數(shù)據(jù)代碼示例及說(shuō)明

更新時(shí)間：2025年03月26日 09:49:02 作者：松香如墨

這篇文章主要介紹了在Java中解析JSON數(shù)據(jù)的相關(guān)資料,文中講解了如何使用Gson和Jackson庫(kù)解析JSON數(shù)據(jù),并展示了如何將日期時(shí)間字符串轉(zhuǎn)換為時(shí)間戳,通過(guò)代碼介紹的非常詳細(xì),需要的朋友可以參考下

例子解析以下JSON數(shù)據(jù)

 {"code":0,
   "msg":"成功",
   "data":            
 [{
"host":"1068222.com",
"port":"",
"m_token":"490e20e70e7de5f21a24b14c12a393f6",
"category":"sd",
"sub_category":"M1049",
"flyback_date":"2025-02-17",
"versions":["0.4.2"],
"req_times":["2025-02-15 02:58:20"],
"create_time":"2025-02-18 06:58:20",
"update_time":"2025-02-18 06:58:20"}]
}

以下以 Gson 庫(kù)為例，展示如何解析這段 JSON 數(shù)據(jù)：

首先，需要在項(xiàng)目中引入 Gson 庫(kù)的依賴(lài)。如果使用 Maven 項(xiàng)目，可以在pom.xml文件中添加以下依賴(lài)：

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.9</version>
</dependency>

接下來(lái)，定義對(duì)應(yīng)的 Java 類(lèi)來(lái)映射 JSON 數(shù)據(jù)結(jié)構(gòu)：

import java.util.List;

public class ResponseData {
    private int code;
    private String msg;
    private List<DataItem> data;

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public List<DataItem> getData() {
        return data;
    }

    public void setData(List<DataItem> data) {
        this.data = data;
    }

    public static class DataItem {
        private String host;
        private String port;
        private String m_token;
        private String category;
        private String sub_category;
        private String flyback_date;
        private List<String> versions;
        private List<String> req_times;
        private String create_time;
        private String update_time;

        public String getHost() {
            return host;
        }

        public void setHost(String host) {
            this.host = host;
        }

        public String getPort() {
            return port;
        }

        public void setPort(String port) {
            this.port = port;
        }

        public String getM_token() {
            return m_token;
        }

        public void setM_token(String m_token) {
            this.m_token = m_token;
        }

        public String getCategory() {
            return category;
        }

        public void setCategory(String category) {
            this.category = category;
        }

        public String getSub_category() {
            return sub_category;
        }

        public void setSub_category(String sub_category) {
            this.sub_category = sub_category;
        }

        public String getFlyback_date() {
            return flyback_date;
        }

        public void setFlyback_date(String flyback_date) {
            this.flyback_date = flyback_date;
        }

        public List<String> getVersions() {
            return versions;
        }

        public void setVersions(List<String> versions) {
            this.versions = versions;
        }

        public List<String> getReq_times() {
            return req_times;
        }

        public void setReq_times(List<String> req_times) {
            this.req_times = req_times;
        }

        public String getCreate_time() {
            return create_time;
        }

        public void setCreate_time(String create_time) {
            this.create_time = create_time;
        }

        public String getUpdate_time() {
            return update_time;
        }

        public void setUpdate_time(String update_time) {
            this.update_time = update_time;
        }
    }
}

然后，使用 Gson 庫(kù)解析 JSON 數(shù)據(jù)：

import com.google.gson.Gson;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

class ResponseData {
    private int code;
    private String msg;
    private List<DataItem> data;

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public List<DataItem> getData() {
        return data;
    }

    public void setData(List<DataItem> data) {
        this.data = data;
    }

    static class DataItem {
        private String host;
        private String port;
        private String m_token;
        private String category;
        private String sub_category;
        private String flyback_date;
        private List<String> versions;
        private List<String> req_times;
        private String create_time;
        private String update_time;

        public String getHost() {
            return host;
        }

        public void setHost(String host) {
            this.host = host;
        }

        public String getPort() {
            return port;
        }

        public void setPort(String port) {
            this.port = port;
        }

        public String getM_token() {
            return m_token;
        }

        public void setM_token(String m_token) {
            this.m_token = m_token;
        }

        public String getCategory() {
            return category;
        }

        public void setCategory(String category) {
            this.category = category;
        }

        public String getSub_category() {
            return sub_category;
        }

        public void setSub_category(String sub_category) {
            this.sub_category = sub_category;
        }

        public String getFlyback_date() {
            return flyback_date;
        }

        public void setFlyback_date(String flyback_date) {
            this.flyback_date = flyback_date;
        }

        public List<String> getVersions() {
            return versions;
        }

        public void setVersions(List<String> versions) {
            this.versions = versions;
        }

        public List<String> getReq_times() {
            return req_times;
        }

        public void setReq_times(List<String> req_times) {
            this.req_times = req_times;
        }

        public String getCreate_time() {
            return create_time;
        }

        public void setCreate_time(String create_time) {
            this.create_time = create_time;
        }

        public String getUpdate_time() {
            return update_time;
        }

        public void setUpdate_time(String update_time) {
            this.update_time = update_time;
        }
    }
}

public class JsonParsingExample {
    public static void main(String[] args) {
        String json = "{\"code\":0,\"msg\":\"成功\",\"data\":[{\"host\":\"1068222.com\",\"port\":\"\",\"m_token\":\"490e20e70e7de5f21a24b14c12a393f6\",\"category\":\"sd\",\"sub_category\":\"M1049\",\"flyback_date\":\"2025-02-17\",\"versions\":[\"0.4.2\"],\"req_times\":[\"2025-02-15 02:58:20\"],\"create_time\":\"2025-02-18 06:58:20\",\"update_time\":\"2025-02-18 06:58:20\"}]}";

        Gson gson = new Gson();
        ResponseData response = gson.fromJson(json, ResponseData.class);

        System.out.println("Code: " + response.getCode());
        System.out.println("Message: " + response.getMsg());

        for (ResponseData.DataItem item : response.getData()) {
            System.out.println("Host: " + item.getHost());
            System.out.println("Port: " + item.getPort());
            System.out.println("m_token: " + item.getM_token());
            System.out.println("Category: " + item.getCategory());
            System.out.println("Sub Category: " + item.getSub_category());
            System.out.println("Flyback Date: " + item.getFlyback_date());
            System.out.println("Versions: " + item.getVersions());
            System.out.println("Req Times: " + item.getReq_times());
            System.out.println("Create Time: " + item.getCreate_time());
            System.out.println("Update Time: " + item.getUpdate_time());

            if (!item.getReq_times().isEmpty()) {
                String firstReqTime = item.getReq_times().get(0);
                try {
                    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                    Date date = sdf.parse(firstReqTime);
                    long timestamp = date.getTime();
                    System.out.println("First Req Time Timestamp: " + timestamp);
                } catch (ParseException e) {
                    System.err.println("Failed to parse date: " + firstReqTime);
                    e.printStackTrace();
                }
            }
        }
    }
}

以上代碼首先定義了與 JSON 數(shù)據(jù)結(jié)構(gòu)對(duì)應(yīng)的 Java 類(lèi)，然后使用 Gson 庫(kù)將 JSON 字符串解析為 Java 對(duì)象，并打印出解析后的數(shù)據(jù)。如果使用 Jackson 庫(kù)，解析過(guò)程會(huì)有所不同，但原理類(lèi)似。

將解析出的 req_times 列表中的第一個(gè)時(shí)間字符串轉(zhuǎn)換為時(shí)間戳。在 Java 中，可以使用 SimpleDateFormat 類(lèi)來(lái)解析日期時(shí)間字符串，并將其轉(zhuǎn)換為 Date 對(duì)象，然后通過(guò) Date 對(duì)象的 getTime() 方法獲取對(duì)應(yīng)的時(shí)間戳。

代碼說(shuō)明：

日期格式化：使用 SimpleDateFormat 類(lèi)，其構(gòu)造函數(shù)傳入 "yyyy-MM-dd HH:mm:ss" 作為日期時(shí)間的格式模板，該模板與 JSON 數(shù)據(jù)中的日期時(shí)間字符串格式相匹配。
解析日期字符串：調(diào)用 SimpleDateFormat 對(duì)象的 parse() 方法將日期時(shí)間字符串解析為 Date 對(duì)象。
獲取時(shí)間戳：通過(guò) Date 對(duì)象的 getTime() 方法獲取對(duì)應(yīng)的時(shí)間戳（從 1970 年 1 月 1 日 00:00:00 UTC 到該日期的毫秒數(shù)）。
異常處理：使用 try-catch 塊捕獲 ParseException 異常，當(dāng)日期時(shí)間字符串格式不符合模板時(shí)，會(huì)拋出該異常，捕獲后打印錯(cuò)誤信息并輸出堆棧跟蹤。