JsonUtils 工具类

package org.jeeyxy.util;

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

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.converter.json.MappingJacksonValue;

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

public class JsonUtils {

	private static Logger logger = LoggerFactory.getLogger(JsonUtils.class);
	private final static ObjectMapper objectMapper = new ObjectMapper();

	private JsonUtils() {

	}

	public static ObjectMapper getInstance() {

		return objectMapper;
	}

	/**
	 * javaBean,list,array convert to json string
	 */
	public static String toJson(Object obj) {
		try {
			return objectMapper.writeValueAsString(obj);
		} catch (Exception ex) {
			logger.warn("write to json string error:" + obj, ex);
			return null;
		}
	}

	/**
	 * json string convert to javaBean
	 */
	public static <T> T toBean(String jsonStr, Class<T> clazz) throws Exception {
		return objectMapper.readValue(jsonStr, clazz);
	}

	/**
	 * json string convert to map
	 */
	public static <T> Map<String, Object> toMap(String jsonStr) throws Exception {
		if (jsonStr != null && !"".equals(jsonStr)) {
			return objectMapper.readValue(jsonStr, Map.class);
		} else {
			return null;
		}
			
		
	}

	/**
	 * json string convert to map with javaBean
	 */
	public static <T> Map<String, T> toMapBean(String jsonStr, Class<T> clazz) throws Exception {
		Map<String, Map<String, Object>> map = objectMapper.readValue(jsonStr, new TypeReference<Map<String, T>>() {
		});
		Map<String, T> result = new HashMap<String, T>();
		for (Entry<String, Map<String, Object>> entry : map.entrySet()) {
			result.put(entry.getKey(), mapToBean(entry.getValue(), clazz));
		}
		return result;
	}

	/**
	 * json array string convert to list with javaBean
	 */
	public static <T> List<T> toList(String jsonArrayStr, Class<T> clazz) throws Exception {
		List<Map<String, Object>> list = objectMapper.readValue(jsonArrayStr, new TypeReference<List<T>>() {
		});
		List<T> result = new ArrayList<T>();
		for (Map<String, Object> map : list) {
			result.add(mapToBean(map, clazz));
		}
		return result;
	}

	/**
	 * map convert to javaBean
	 */
	public static <T> T mapToBean(Map map, Class<T> clazz) {
		return objectMapper.convertValue(map, clazz);
	}
    public static MappingJacksonValue jsonp(Object value,String callback){
        MappingJacksonValue mappingJacksonValue = new MappingJacksonValue(value);
        mappingJacksonValue.setJsonpFunction(callback);
        return mappingJacksonValue;
    }
}