java拼接字符串

#1.使用String对象（产生大量的垃圾中间String对象）

    public void useString(String[] args) {
        String result = "";
        for (int i = 0; i < args.length; i++) {
            if (i != 0) {
                result += ",";
            }
            result += args[i];
        }
        System.out.println(result);
    }

#2.使用StringBuilder对象（推荐）

    public void useStringBuilder(String[] args) {
        StringBuilder result = new StringBuilder();
        for (int i = 0; i < args.length; i++) {
            if (i != 0) {
                result.append(",");
            }
            result.append(args[i]);
        }
        System.out.println(result.toString());
    }