Java将List/JavaBean转成Json

import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.util.List;
/**
* json的操作类
*
* @author wsz
* @createTime 2012-4-12
* @version 1.0
*/
public class JsonUtil {
    /**
     * 传入任意一个 object对象生成一个指定规格的字符串
     *
     * @param object 任意对象
     * @return String
     */
    public static String objectToJson(Object object) {
        StringBuilder json = new StringBuilder();
        if (object == null) {
            json.append("\"\"");
        } else if (object instanceof String || object instanceof Integer || object instanceof Double) {
            json.append("\"").append(object.toString()).append("\"");
        } else {
            json.append(beanToJson(object));
        }
        return json.toString();
    }
    /**
     * 传入任意一个 Javabean对象生成一个指定规格的字符串
     *
     * @param bean bean对象
     * @return String "{}"
     */
    public static String beanToJson(Object bean) {
        StringBuilder json = new StringBuilder();
        json.append("{");
        PropertyDescriptor[] props = null;
        try {
            props = Introspector.getBeanInfo(bean.getClass(), Object.class).getPropertyDescriptors();
        } catch (Exception e) {
            e.printStackTrace();
        }
        if (props != null) {
            for (int i = 0; i < props.length; i++) {
                try {
                    String name = objectToJson(props[i].getName());
                    String value = objectToJson(props[i].getReadMethod().invoke(bean));
                    json.append(name);
                    json.append(":");
                    json.append(value);
                    json.append(",");
                } catch (Exception e) {
                }
            }
            json.setCharAt(json.length() - 1, '}');
        } else {
            json.append("}");
        }
        return json.toString();
    }
    /**
     * 通过传入一个列表对象,调用指定方法将列表中的数据生成一个JSON规格指定字符串
     *
     * @param list 列表对象
     * @return String "[{},{}]"
     */
    public static String listToJson(List<?> list) {
        StringBuilder json = new StringBuilder();
        json.append("[");
        if (list != null && list.size() > 0) {
            for (Object obj : list) {
                json.append(objectToJson(obj));
                json.append(",");
            }
            json.setCharAt(json.length() - 1, ']');
        } else {
            json.append("]");
        }
        return json.toString();
    }
}