前言

今天給大家分享的是操作json的工具類，使用的是jackson，如果你使用的是spring boot的話直接引入spring-boot-starter-parent響應的包會自動引入。

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
    </parent>
 

或maven引入

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.2</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId
 
>jackson-core</artifactId>
    <version>2.9.2</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.9.2</version>
</dependency>

程式碼

package
 
 com.zhuma.demo.util;

import java.util.ArrayList;
import java.util.List;

import org.springframework.util.StringUtils;

import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * @desc JSON操作工具類
 * 
 * @author zhumaer
 * @since 6/20/2017 16:37 PM
 */
public class JsonUtil {

    private static ObjectMapper mapper = new ObjectMapper();

    static {
        mapper.setSerializationInclusion(Include.NON_NULL);
        //設定輸入時忽略JSON字串中存在而Java物件實際沒有的屬性
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    }

    public static String object2Json(Object o) {
        if (o == null)
            return null;

        String s = null;

        try {
            s = mapper.writeValueAsString(o);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return s;
    }

    public static <T> List<String> listObject2ListJson(List<T> objects) {
        if (objects == null)
            return null;

        List<String> lists = new ArrayList<String>();
        for (T t : objects) {
            lists.add(JsonUtil.object2Json(t));
        }

        return lists;
    }

    public static <T> List<T> listJson2ListObject(List<String> jsons, Class<T> c) {
        if (jsons == null)
            return null;

        List<T> ts = new ArrayList<T>();
        for (String j : jsons) {
            ts.add(JsonUtil.json2Object(j, c));
        }

        return ts;
    }

    public static <T> T json2Object(String json, Class<T> c) {
        if (StringUtils.hasLength(json) == false)
            return null;

        T t = null;
        try {
            t = mapper.readValue(json, c);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return t;
    }

    @SuppressWarnings("unchecked")
    public static <T> T json2Object(String json, TypeReference<T> tr) {
        if (StringUtils.hasLength(json) == false)
            return null;

        T t = null;
        try {
            t = (T) mapper.readValue(json, tr);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return (T) t;
    }
}

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