java jsonUtil

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;

/**
 * 通用的全局JSON处理工具类
 *
 * @version $Id$
 */

public class JsonUtils {

    private static ObjectMapper objectMapper = new ObjectMapper();

    static {
       objectMapper = ObjectMapperBuilder.newBuilder()
                            .withDefaultOptions()
                            .withDateTimeModule()
                            .build();
    }

    public static ObjectMapper getGlobalObjectMapper() {
        return objectMapper;
    }


    /**
     * 把对象转为json字符串
     *
     * @param obj 要转换的对象 可以为null
     * @return
     */
    public static String toJson(Object obj) {
        try {
            return objectMapper.writeValueAsString(obj);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 把json字符串转为对象
     *
     * @param json 要转换的字符串
     * @param cls  目标实例类名
     * @param <T>
     * @return
     */

    public static <T> T toBean(String json, Class<T> cls) {
        try {
            return (T) objectMapper.readValue(json, cls);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 把json字符串转为对象，给定类型信息
     *
     * @param json          要装换的字符串
     * @param typeReference 类型引用
     * @param <T>
     * @return
     */
    public static <T> T toBean(String json, TypeReference typeReference) {
        try {
            return (T) objectMapper.readValue(json, typeReference);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

    }
}