Jackson2.x通用工具类

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.TimeZone;

import org.apache.log4j.Logger;

import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

public class JsonUtils {
    private static Logger logger = Logger.getLogger(JsonUtils.class);
    private static final ObjectMapper objectMapper;
    static {
        objectMapper = new ObjectMapper();
        //去掉默认的时间戳格式
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        //设置为中国上海时区
        objectMapper.setTimeZone(TimeZone.getTimeZone("GMT+8"));
        objectMapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);
        //空值不序列化
        objectMapper.setSerializationInclusion(Include.NON_NULL);
        //反序列化时，属性不存在的兼容处理
        objectMapper.getDeserializationConfig().withoutFeatures(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        //序列化时，日期的统一格式
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));

        objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        //单引号处理
        objectMapper.configure(com.fasterxml.jackson.core.JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
    }

    public static <T> T toObject(String json, Class<T> clazz) {
        try {
            return objectMapper.readValue(json, clazz);
        } catch (JsonParseException e) {
            logger.error(e.getMessage(), e);
        } catch (JsonMappingException e) {
            logger.error(e.getMessage(), e);
        } catch (IOException e) {
            logger.error(e.getMessage(), e);
        }
        return null;
    }

    public static <T> String toJson(T entity) {
        try {
            return objectMapper.writeValueAsString(entity);
        } catch (JsonGenerationException e) {
            logger.error(e.getMessage(), e);
        } catch (JsonMappingException e) {
            logger.error(e.getMessage(), e);
        } catch (IOException e) {
            logger.error(e.getMessage(), e);
        }
        return null;
    }

    public static <T> T toCollection(String json, TypeReference<T> typeReference) {
        try {
            return objectMapper.readValue(json, typeReference);
        } catch (JsonParseException e) {
            logger.error(e.getMessage(), e);
        } catch (JsonMappingException e) {
            logger.error(e.getMessage(), e);
        } catch (IOException e) {
            logger.error(e.getMessage(), e);
        }
        return null;
    }

}