java 将复杂对象转化为Json

/*


import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * <p>
 * Class Name: 类名称
 * </p>
 * <p>
 * Description: 将复杂对象转化为Json
 * </p>
 * <p>
 * Sample: 该类的典型使用方法和用例
 * </p>
 * <p>
 * Author: liuming
 * </p>
 * <p>
 * Date: 创建时间
 * </p>
 * <p>
 * Modified History: 修改记录，格式(Name) (Version) (Date) (Reason & Contents)
 * </p>
 */
public class Json {
	/** Commons Logging instance. */
	private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory.getLog(Json.class);

	/**
	 * @param obj 任意对象
	 * @return String
	 */
	public static String object2json(Object obj) {
		StringBuffer json = new StringBuffer();
		if (obj == null) {
			json.append("\"\"");
		} else if (obj instanceof String || obj instanceof Integer || obj instanceof Float || obj instanceof Boolean
				|| obj instanceof Short || obj instanceof Double || obj instanceof Long || obj instanceof BigDecimal
				|| obj instanceof BigInteger || obj instanceof Byte) {
			json.append("\"").append(string2json(obj.toString())).append("\"");
		} else if (obj instanceof Object[]) {
			json.append(array2json((Object[]) obj));
		} else if (obj instanceof List) {
			json.append(list2json((List) obj));
		} else if (obj instanceof Map) {
			json.append(map2json((Map) obj));
		} else if (obj instanceof Set) {
			json.append(set2json((Set) obj));
		} else {
			json.append(bean2json(obj));
		}
		return json.toString();
	}

	/**
	 * @param bean bean对象
	 * @return String
	 */
	public static String bean2json(Object bean) {
		StringBuffer json = new StringBuffer();
		json.append("{");
		PropertyDescriptor[] props = null;
		try {
			props = Introspector.getBeanInfo(bean.getClass(), Object.class).getPropertyDescriptors();
		} catch (IntrospectionException e) {
			e.printStackTrace();
		}
		if (props != null) {
			for (int i = 0; i < props.length; i++) {
				try {
				
					String name = object2json(props[i].getName());
					String value = object2json(props[i].getReadMethod().invoke(bean, new Object [] {}));
					json.append(name);
					json.append(":");
					json.append(value);
					json.append(",");
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
			json.setCharAt(json.length() - 1, '}');
		} else {
			json.append("}");
		}
		return json.toString();
	}

	/**
	 * @param list list对象
	 * @return String
	 */
	public static String list2json(List list) {
		StringBuffer json = new StringBuffer();
		json.append("[");
		if (list != null && list.size() > 0) {
			for (int i = 0, n = list.size(); i < n; i++) {
				json.append(object2json(list.get(i)));
				json.append(",");
			}
			json.setCharAt(json.length() - 1, ']');
		} else {
			json.append("]");
		}
		return json.toString();
	}

	/**
	 * @param array 对象数组
	 * @return String
	 */
	public static String array2json(Object[] array) {
		StringBuffer json = new StringBuffer();
		json.append("[");
		if (array != null && array.length > 0) {
			for (int i = 0, n = array.length; i < n; i++) {
				json.append(object2json(array[i]));
				json.append(",");
			}
			json.setCharAt(json.length() - 1, ']');
		} else {
			json.append("]");
		}
		return json.toString();
	}

	/**
	 * @param map map对象
	 * @return String
	 */
	public static String map2json(Map map) {
		StringBuffer json = new StringBuffer();
		json.append("{");
		if (map != null && map.size() > 0) {
			Set set = map.entrySet();
			for (Iterator iterator = set.iterator(); iterator.hasNext();) {
				Map.Entry entry = (Map.Entry) iterator.next();
				json.append(object2json(entry.getKey()));
				json.append(":");
				json.append(object2json(entry.getValue()));
				json.append(",");
			}
			json.setCharAt(json.length() - 1, '}');
		} else {
			json.append("}");
		}
		return json.toString();
	}

	/**
	 * @param set 集合对象
	 * @return String
	 */
	public static String set2json(Set set) {
		StringBuffer json = new StringBuffer();
		json.append("[");
		if (set != null && set.size() > 0) {
			for (Iterator iterator = set.iterator(); iterator.hasNext();) {
				json.append(object2json(iterator.next()));
				json.append(",");
			}
			json.setCharAt(json.length() - 1, ']');
		} else {
			json.append("]");
		}
		return json.toString();
	}

	/**
	 * @param s 参数
	 * @return String
	 */
	public static String string2json(String s) {
		if (s == null)
			return "";
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < s.length(); i++) {
			char ch = s.charAt(i);
			switch (ch) {
			case '"':
				sb.append("\\\"");
				break;
			case '\\':
				sb.append("\\\\");
				break;
			case '\b':
				sb.append("\\b");
				break;
			case '\f':
				sb.append("\\f");
				break;
			case '\n':
				sb.append("\\n");
				break;
			case '\r':
				sb.append("\\r");
				break;
			case '\t':
				sb.append("\\t");
				break;
			case '/':
				sb.append("\\/");
				break;
			default:
				if (ch >= '\u0000' && ch <= '\u001F') {
					String ss = Integer.toHexString(ch);
					sb.append("\\u");
					for (int k = 0; k < 4 - ss.length(); k++) {
						sb.append('0');
					}
					sb.append(ss.toUpperCase());
				} else {
					sb.append(ch);
				}
			}
		}
		return sb.toString();
	}
}