java知识点:dom4j 由map转字符串

map.toString()是这样子的~

{welcome-file-list={welcome-file=[index.html, {a=[{b=[{c=[c1c1c1c1c1c1, c2c2c2c2c2c2]}, b2b2b2b2]}, 22222, 33333]}, index.jsp, default.html, default.htm, default.jsp]}, display-name=ask-ssh, context-param={param-value=classpath:applicationContext.xml, param-name=contextConfigLocation},
filter-mapping={url-pattern=/*, filter-name=struts2}, listener={listener-class=org.springframework.web.context.ContextLoaderListener}, filter={filter-class=org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter, filter-name=struts2}}

观察发现,由map 套 list 套 map

思路:

1. 遍历map
2. 判断 value 是否是一个Map
3. 判断 value 是否是一个List
4. 判断List中是否有Map
5. 递归

需要注意的是:在每个循环开始和结尾都需要加上 sb.append("<" + key + ">"); sb.append("</" + key + ">");

而中间是否要放值,取决于你是Map?是List?是String? 只有String才放值

	public static String map2Dom(Map<String, Object> map) {
		// iterator法,遍历map
		Iterator keyIterator = map.keySet().iterator();
		StringBuffer sb = new StringBuffer();

		while (keyIterator.hasNext()) {
			String key = (String) keyIterator.next();
			Object value = map.get(key);

			// 如果value是map则调用map2Dom
			if ("java.util.HashMap".equals(value.getClass().getName())) {
				mapAppend(sb, key, value);
			} else {
				// 不是map,判断是否是list
				if ("java.util.ArrayList".equals(value.getClass().getName())) {
					for (Object tmpObject : (List) value) {
						// 如果是map,则调用map2Dom
						// 此时就变成一开始的样子了`~~
						if ("java.util.HashMap".equals(tmpObject.getClass()
								.getName())) {
							mapAppend(sb, key, tmpObject);
						} else {
							// "java.lang.String"
							stringAppend(sb, key, tmpObject);
						}
					}
				} else {
					stringAppend(sb, key, value);
				}
			}
		}
		return sb.toString();
	}

    private static void stringAppend(StringBuffer sb, String key,
            Object tmpObject) {
        sb.append("<" + key + ">");
        sb.append(tmpObject);
        sb.append("</" + key + ">");
    }

    private static void mapAppend(StringBuffer sb, String key, Object tmpObject) {
        sb.append("<" + key + ">");
        sb.append(map2Dom((Map<String, Object>) tmpObject));
        sb.append("</" + key + ">");
    }