/**
 * @author ***
 * @title: Test2
 * @projectName osaos
 * @description TODO
 * @date 2021/9/26 15:31
 */
public class Test2 {

    public static void main(String[] args) {
        Map<String,String> map = new TreeMap<>();
        map.put("b","b");
        map.put("a","a");

        String s = joinMapValue(map, '&');
        System.out.println(s);

    }

    public static String joinMapValue(Map<String, String> map, char connector) {
        StringBuffer sb = new StringBuffer();
        for (Map.Entry<String, String> entry : map.entrySet()) {
            sb.append(entry.getKey());
            sb.append('=');
            if (entry.getValue() != null) {
                sb.append(entry.getValue());
            }
            sb.append(connector);
        }
        return sb.toString();
    }
}