bean和json相互轉換工具類（工具ObjectMapper）

package util;


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

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

/**
 * Created by shangyl on 15/4/21.
 * json處理類
 */
@SuppressWarnings({"unchecked"})
public class JacksonUtil {
    private static ObjectMapper objectMapper;

    static {
        objectMapper = generateMapper(JsonInclude.Include.NON_EMPTY);
    }

    private JacksonUtil() {
    }

    /**
     * 將json經過類型轉換成對象
     */
    public static <T> T fromJson(String json, Class<T> clazz)
            throws IOException {
        return clazz.equals(String.class) ? (T) json : objectMapper.readValue(json,
                clazz);
    }

    /**
     * 將json經過類型轉換成對象
     */

    public static <T> T fromJson(String json, TypeReference<?> typeReference)
            throws IOException {
        return (T) (typeReference.getType().equals(String.class) ? json
                : objectMapper.readValue(json, typeReference));
    }

    /**
     * 將對象轉換成json
     */
    public static <T> String toJson(T src) throws IOException {
        return src instanceof String ? (String) src : objectMapper
                .writeValueAsString(src);
    }

    /**
     * 將對象轉換成json, 能夠設置輸出屬性
     */
    public static <T> String toJson(T src, JsonInclude.Include include)
            throws IOException {
        if (src instanceof String) {
            return (String) src;
        } else {
            ObjectMapper customMapper = generateMapper(include);
            return customMapper.writeValueAsString(src);
        }
    }

    /**
     * 將對象轉換成json, 傳入配置對象
     */
    public static <T> String toJson(T src, ObjectMapper mapper)
            throws IOException {
        if (null != mapper) {
            if (src instanceof String) {
                return (String) src;
            } else {
                return mapper.writeValueAsString(src);
            }
        } else {
            return null;
        }
    }

    /**
     */
    public static ObjectMapper mapper() {
        return objectMapper;
    }

    /**
     * 經過Inclusion建立ObjectMapper對象
     */
    private static ObjectMapper generateMapper(JsonInclude.Include include) {

        ObjectMapper customMapper = new ObjectMapper();

        // 設置輸出時包含屬性的風格

        customMapper.setSerializationInclusion(include);

        // 設置輸入時忽略在JSON字符串中存在但Java對象實際沒有的屬性
        // customMapper.configure(Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        // 禁止使用int表明Enum的order()來反序列化Enum,很是危險
        // customMapper.configure(Feature.FAIL_ON_NUMBERS_FOR_ENUMS, true);

        // 全部日期格式都統一爲如下樣式
        customMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));

        return customMapper;
    }
}