jsonUtil 工具类

package org.konghao.basic.util;

import java.io.IOException;
import java.io.StringWriter;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JsonUtil {
    private static JsonUtil ju;
    private static JsonFactory jf;
    private static ObjectMapper mapper;

    private JsonUtil() {
    }

    public static JsonUtil getInstance() {
        if (ju == null)
            ju = new JsonUtil();
        return ju;
    }

    public static ObjectMapper getMapper() {
        if (mapper == null) {
            mapper = new ObjectMapper();
        }
        return mapper;
    }

    public static JsonFactory getFactory() {
        if (jf == null)
            jf = new JsonFactory();
        return jf;
    }

    public String obj2json(Object obj) {
        JsonGenerator jg = null;
        try {
            jf = getFactory();
            mapper = getMapper();
            StringWriter out = new StringWriter();
            jg = jf.createJsonGenerator(out);
            mapper.writeValue(jg, obj);
            return out.toString();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (jg != null)
                    jg.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    public Object json2obj(String json, Class<?> clz) {
        try {
            mapper = getMapper();
            return mapper.readValue(json, clz);
        } catch (JsonParseException e) {
            e.printStackTrace();
        } catch (JsonMappingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }


}