simulation-cloud/api-common/src/main/java/api/common/util/JsonUtil.java

package api.common.util;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.TextNode;
import com.fasterxml.jackson.databind.type.TypeFactory;


import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class JsonUtil {

    private static final ObjectMapper mapper = new ObjectMapper();


    /**
     * bean 转成 json
     *
     * @param bean bean 对象
     * @param <T>  声明为泛型方法
     * @return json 字符串
     * @throws JsonProcessingException 异常
     */
    public static <T> String beanToJson(T bean) throws JsonProcessingException {
        return new ObjectMapper().writeValueAsString(bean);
    }

    /**
     * json 转成 bean
     *
     * @param json   json 字符串
     * @param tClass 返回值类型
     * @param <T>    声明为泛型方法
     * @return bean 对象
     * @throws JsonProcessingException 异常
     */
    public static <T> T jsonToBean(String json, Class<T> tClass) throws JsonProcessingException {
        return new ObjectMapper().readValue(json, tClass);
    }

    /**
     * bean 转成 json
     *
     * @param list 列表对象
     * @param <T>  声明为泛型方法
     * @return json 字符串
     * @throws JsonProcessingException 异常
     */
    public static <T> String listToJson(T list) throws JsonProcessingException {
        return new ObjectMapper().writeValueAsString(list);
    }

    public static <T> List<T> jsonToList(String json, Class<T> tClass) throws JsonProcessingException {
        JavaType javaType = TypeFactory.defaultInstance().constructParametricType(List.class, tClass);
        if(ObjectUtil.isNull(json)){
            return new ArrayList<>();
        }
        List<T> list = new ObjectMapper().readValue(json,javaType);
        return list;
    }

    public static Map jsonToMap(String json) {
        try {
            return new ObjectMapper().readValue(json, HashMap.class);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return new HashMap();
    }

    public static JsonNode readTree(String json) {
        try {
            JsonNode jsonNode = mapper.readTree(json);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return new TextNode("");
    }
}