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使用Jackson封裝常用的JsonUtil工具類方式

更新時(shí)間：2025年06月29日 13:24:29 作者：yuhuofei2021

這篇文章主要介紹了使用Jackson封裝常用的JsonUtil工具類方式,具有很好的參考價(jià)值,希望對(duì)大家有所幫助,如有錯(cuò)誤或未考慮完全的地方,望不吝賜教

1. 引入依賴包

在 pom.xml 文件中加入以下依賴

<!-- 引入jackson依賴包-->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.14.2</version>
</dependency>

2. 編寫 JsonUtil 工具類

package com.yuhuofei.utils;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import lombok.extern.slf4j.Slf4j;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;

/**
 * @Description 由于習(xí)慣了用fastjson處理JSON數(shù)據(jù)，突然改成用jackson，有些不適應(yīng)，所以打算用jackson封裝出類似fastjson里的方法進(jìn)行使用
 * @ClassName JsonUtil
 * @Author yuhuofei
 * @Date 2023/8/19 14:36
 * @Version 1.0
 */
@Slf4j
public class JsonUtil {

    private static ObjectMapper objectMapper = new ObjectMapper();

    // 時(shí)間日期格式
    private static final String STANDARD_FORMAT = "yyyy-MM-dd HH:mm:ss";

    //以靜態(tài)代碼塊初始化
    static {
        //對(duì)象的所有字段全部列入序列化
        objectMapper.setSerializationInclusion(JsonInclude.Include.ALWAYS);
        //取消默認(rèn)轉(zhuǎn)換timestamps形式
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        //忽略空Bean轉(zhuǎn)json的錯(cuò)誤
        objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
        //所有的日期格式都統(tǒng)一為以下的格式，即yyyy-MM-dd HH:mm:ss
        objectMapper.setDateFormat(new SimpleDateFormat(STANDARD_FORMAT));
        //忽略 在json字符串中存在，但在java對(duì)象中不存在對(duì)應(yīng)屬性的情況。防止錯(cuò)誤
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    }


    /**===========================以下是從JSON中獲取對(duì)象====================================*/
    public static <T> T parseObject(String jsonString, Class<T> object) {
        T t = null;
        try {
            t = objectMapper.readValue(jsonString, object);
        } catch (JsonProcessingException e) {
            log.error("JsonString轉(zhuǎn)為自定義對(duì)象失?。簕}", e.getMessage());
        }
        return t;
    }

    public static <T> T parseObject(File file, Class<T> object) {
        T t = null;
        try {
            t = objectMapper.readValue(file, object);
        } catch (IOException e) {
            log.error("從文件中讀取json字符串轉(zhuǎn)為自定義對(duì)象失?。簕}", e.getMessage());
        }
        return t;
    }

    //將json數(shù)組字符串轉(zhuǎn)為指定對(duì)象List列表或者M(jìn)ap集合
    public static <T> T parseJSONArray(String jsonArray, TypeReference<T> reference) {
        T t = null;
        try {
            t = objectMapper.readValue(jsonArray, reference);
        } catch (JsonProcessingException e) {
            log.error("JSONArray轉(zhuǎn)為L(zhǎng)ist列表或者M(jìn)ap集合失?。簕}", e.getMessage());
        }
        return t;
    }


    /**=================================以下是將對(duì)象轉(zhuǎn)為JSON=====================================*/
    public static String toJSONString(Object object) {
        String jsonString = null;
        try {
            jsonString = objectMapper.writeValueAsString(object);
        } catch (JsonProcessingException e) {
            log.error("Object轉(zhuǎn)JSONString失敗：{}", e.getMessage());
        }
        return jsonString;
    }

    public static byte[] toByteArray(Object object) {
        byte[] bytes = null;
        try {
            bytes = objectMapper.writeValueAsBytes(object);
        } catch (JsonProcessingException e) {
            log.error("Object轉(zhuǎn)ByteArray失?。簕}", e.getMessage());
        }
        return bytes;
    }

    public static void objectToFile(File file, Object object) {
        try {
            objectMapper.writeValue(file, object);
        } catch (JsonProcessingException e) {
            log.error("Object寫入文件失敗：{}", e.getMessage());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    /**=============================以下是與JsonNode相關(guān)的=======================================*/
    //JsonNode和JSONObject一樣，都是JSON樹形模型，只不過(guò)在jackson中，存在的是JsonNode
    public static JsonNode parseJSONObject(String jsonString) {
        JsonNode jsonNode = null;
        try {
            jsonNode = objectMapper.readTree(jsonString);
        } catch (JsonProcessingException e) {
            log.error("JSONString轉(zhuǎn)為JsonNode失?。簕}", e.getMessage());
        }
        return jsonNode;
    }

    public static JsonNode parseJSONObject(Object object) {
        JsonNode jsonNode = objectMapper.valueToTree(object);
        return jsonNode;
    }

    public static String toJSONString(JsonNode jsonNode) {
        String jsonString = null;
        try {
            jsonString = objectMapper.writeValueAsString(jsonNode);
        } catch (JsonProcessingException e) {
            log.error("JsonNode轉(zhuǎn)JSONString失?。簕}", e.getMessage());
        }
        return jsonString;
    }

    //JsonNode是一個(gè)抽象類，不能實(shí)例化，創(chuàng)建JSON樹形模型，得用JsonNode的子類ObjectNode，用法和JSONObject大同小異
    public static ObjectNode newJSONObject() {
        return objectMapper.createObjectNode();
    }

    //創(chuàng)建JSON數(shù)組對(duì)象，就像JSONArray一樣用
    public static ArrayNode newJSONArray() {
        return objectMapper.createArrayNode();
    }


    /**===========以下是從JsonNode對(duì)象中獲取key值的方法，個(gè)人覺(jué)得有點(diǎn)多余，直接用JsonNode自帶的取值方法會(huì)好點(diǎn)，出于糾結(jié)癥，還是補(bǔ)充進(jìn)來(lái)了*/
    public static String getString(JsonNode jsonObject, String key) {
        String s = jsonObject.get(key).asText();
        return s;
    }

    public static Integer getInteger(JsonNode jsonObject, String key) {
        Integer i = jsonObject.get(key).asInt();
        return i;
    }

    public static Boolean getBoolean(JsonNode jsonObject, String key) {
        Boolean bool = jsonObject.get(key).asBoolean();
        return bool;
    }

    public static JsonNode getJSONObject(JsonNode jsonObject, String key) {
        JsonNode json = jsonObject.get(key);
        return json;
    }
}

3. 測(cè)試

新建一個(gè) User 類

package com.yuhuofei.entity;

import lombok.Data;

import java.io.Serializable;

/**
 * @Description
 * @ClassName User
 * @Author yuhuofei
 * @Date 2023/8/19 14:49
 * @Version 1.0
 */
@Data
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    private Integer id;

    private String name;

    private String passWord;
}

新建一個(gè)測(cè)試類

import com.yuhuofei.entity.User;
import com.yuhuofei.utils.JsonUtil;

/**
 * @Description
 * @ClassName TestJsonUtil
 * @Author yuhuofei
 * @Date 2023/8/19 14:58
 * @Version 1.0
 */
public class TestJsonUtil {

    public static void main(String[] args) {

        String jsonString = "{\"id\":11,\"name\":\"小明\",\"passWord\":\"123456\"}";
        User user = JsonUtil.parseObject(jsonString, User.class);
        System.out.println(user);
    }
}

執(zhí)行 main 方法測(cè)試，可以看到在控制臺(tái)正確地輸出了結(jié)果。

在這里插入圖片描述