JSONUtil工具类

import java.util.HashMap;import java.util.Map;import com.alibaba.druid.util.StringUtils;import com.alibaba.fastjson.JSON;import com.alibaba.fastjson.JSONObject;public class JSONUtils {    /**     * Bean对象转JSON     *      * @param object     * @param dataFormatString     * @return     */    public static String beanToJson(Object object, String dataFormatString) {        if (object != null) {            if (StringUtils.isEmpty(dataFormatString)) {                return JSONObject.toJSONString(object);            }            return JSON.toJSONStringWithDateFormat(object, dataFormatString);        } else {            return null;        }    }    /**     * Bean对象转JSON     *      * @param object     * @return     */    public static String beanToJson(Object object) {        if (object != null) {            return JSON.toJSONString(object);        } else {            return null;        }    }    /**     * String转JSON字符串     *      * @param key     * @param value     * @return     */    public static String stringToJsonByFastjson(String key, String value) {        if (StringUtils.isEmpty(key) || StringUtils.isEmpty(value)) {            return null;        }        Map<String, String> map = new HashMap<String, String>();        map.put(key, value);        return beanToJson(map, null);    }    /**     * 将json字符串转换成对象     *      * @param json     * @param clazz     * @return     */    public static Object jsonToBean(String json, Object clazz) {        if (StringUtils.isEmpty(json) || clazz == null) {            return null;        }        return JSON.parseObject(json, clazz.getClass());    }    /**     * json字符串转map     *      * @param json     * @return     */    @SuppressWarnings("unchecked")    public static Map<String, Object> jsonToMap(String json) {        if (StringUtils.isEmpty(json)) {            return null;        }        return JSON.parseObject(json, Map.class);    }}

测试：
JSON字符串转map

public static void main(String[] args) {        String jsonStr = "{'userName':'huangbaokang','password':'123456'}";        Map<String, Object> map = JSONUtils.jsonToMap(jsonStr);        System.out.println(map.get("userName"));    }

输出：huangbaokang

JSON字符串转对象：
新建User类

public class User {    private String userName;    private String password;    public String getUserName() {        return userName;    }    public void setUserName(String userName) {        this.userName = userName;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }}

public static void main(String[] args) {        String jsonStr = "{'userName':'huangbaokang','password':'123456'}";        User user = (User) JSONUtils.jsonToBean(jsonStr, new User());        System.out.println("用户名="+user.getUserName()+" 密码="+user.getPassword());    }

测试：输出用户名=huangbaokang 密码=123456

对象转JSON

public static void main(String[] args) {        User user = new User();        user.setUserName("huangbaokang");        user.setPassword("123456");        String result = JSONUtils.beanToJson(user);        System.out.println(result);    }

测试输出：{“password”:”123456”,”userName”:”huangbaokang”}

在这里工具类应用的jar为阿里巴巴的fastjson，在lib中加入相关jar。