java将JSON字符串格式化到控制台的工具类

final class FormatUtil {

    /**
     * 打印输入到控制台
     *
     * @param jsonStr
     * @author lizhgb
     * @Date 2015-10-14 下午1:17:22
     */
    public static void printJson(String jsonStr) {
        System.out.println(formatJson(jsonStr));
    }

    /**
     * 格式化
     * @param jsonStr
     * @return
     * @author lizhgb
     * @Date 2015-10-14 下午1:17:35
     * @Modified 2017-04-28 下午8:55:35
     */
    public static String formatJson(String jsonStr)
    {
        if (null == jsonStr || "".equals(jsonStr))
        {
            return "";
        }
        StringBuilder sb = new StringBuilder();
        char last = '\0';
        char current = '\0';
        int indent = 0;
        boolean isInQuotationMarks = false;
        for (int i = 0; i < jsonStr.length(); i++)
        {
            last = current;
            current = jsonStr.charAt(i);
            switch (current)
            {
                case '"':
                    if (last != '\\')
                    {
                        isInQuotationMarks = !isInQuotationMarks;
                    }
                    sb.append(current);
                    break;

                case '{':
                case '[':
                    sb.append(current);
                    if (!isInQuotationMarks)
                    {
                        sb.append('\n');
                        indent++;
                        addIndentBlank(sb, indent);
                    }
                    break;

                case '}':
                case ']':
                    if (!isInQuotationMarks)
                    {
                        sb.append('\n');
                        indent--;
                        addIndentBlank(sb, indent);
                    }
                    sb.append(current);
                    break;

                case ',':
                    sb.append(current);
                    if (last != '\\' && !isInQuotationMarks)
                    {
                        sb.append('\n');
                        addIndentBlank(sb, indent);
                    }
                    break;

                default:
                    sb.append(current);
            }
        }

        return sb.toString();
    }

    /**
     * 添加space
     *
     * @param sb
     * @param indent
     * @author lizhgb
     * @Date 2015-10-14 上午10:38:04
     */
    private static void addIndentBlank(StringBuilder sb, int indent)
    {
        for (int i = 0; i < indent; i++)
        {
            sb.append('\t');
        }
    }
}