fastJson详解_fastjson indent

 关系图：

解析JSON文本为带格式JSON文本
public final class FormatJsonUtil {
    /**
     * 打印输入到控制台
     *
     * @param jsonStr
     */
    public static void printJson(String jsonStr) {
        System.out.println(formatJson(jsonStr));
    }
    /**
     * 格式化
     *
     * @param jsonStr
     */
    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;  // "{\"planId\": \"\"}"
                }                                              //  T       F   T F
                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
     */
    private static void addIndentBlank(StringBuilder sb, int indent) {
        for (int i = 0; i < indent; i++) {
            sb.append('\t');
        }
    }
   
}

Encode代码示例：
import com.alibaba.fastjson.JSON;
 
Group group = new Group();
group.setId(0L);
group.setName("admin");
User guestUser = new User();
guestUser.setId(2L);
guestUser.setName("guest");
User rootUser = new User();
rootUser.setId(3L);
rootUser.setName("root");
group.getUsers().add(guestUser);
group.getUsers().add(rootUser);
String jsonString = JSON.toJSONString(group);
System.out.println(jsonString);
 
Decode 代码示例：
Group group2 = JSON.parseObject(jsonString, Group.class);