java jackson 读写修改json文件

json数据格式：
// {"test":[{"volume":234,"driver":[{"ip":"192.168.1.1"},{"ip":"192.168.1.2"},{"ip":"192.168.1.3"}]},{"volume":234123,"driver":[{"ip":"192.168.1.1"},{"ip":"192.168.1.2"},{"ip":"192.168.1.3"}]}]}
//读
synchronized public static boolean existInMultiPathConfigFile(long volumeId) {
        try {
            ObjectMapper objMap = new ObjectMapper();
            System.out.println("array size is 111111111111111111");
            JsonNode root = objMap.readTree(new File("/home/test/multipaths.conf"));
            System.out.println("array size is 2222222222222222222222");
            JsonNode node = root.path("test");
            System.out.println("array size is " + node.size());

            for (int i = 0; i < node.size(); i++) {
                Long volume = node.path(i).path("volume").asLong();
                if (volume.equals(volumeId)) {
                    System.out.println("exist connection in multipaths.conf.");
                    return true;
                }
            }
        } catch (Exception ex) {
            System.out.println("error to read config file.");
            return false;
        }
        System.out.println("nonexist@@@@@@@@@@@@@@@@@@@@.");
        return false;
    }

//写
    synchronized public static boolean writeMultiPathConfigFile(long volumeId, List<String> ips) {
        try {
            ObjectMapper objMap = new ObjectMapper();
            JsonNode root = objMap.readTree(new File("/home/test/multipaths.conf"));
            ArrayNode node = (ArrayNode)root.path("test");
            ObjectNode newNode = objMap.createObjectNode();
            newNode.put("volume", volumeId);
            ArrayNode ipArray = objMap.createArrayNode();
            for (String ip : ips) {
                ObjectNode ipNode = objMap.createObjectNode();
                ipNode.put("ip", ip);
                ipArray.add(ipNode);
            }
            newNode.put("driver", ipArray);
            node.add(newNode);
            OutputStream outputStream = new FileOutputStream(new File("/home/test/multipaths.conf"));
            objMap.writeValue(outputStream, root);
        } catch (Exception ex) {
            System.out.println("error to read config file.");
            return true;
        }
        return false;
    }

//删除
    synchronized public static boolean eraseMultiPathConfigFile(long volumeId) {
        try {
            ObjectMapper objMap = new ObjectMapper();
            JsonNode root = objMap.readTree(new File("/home/test/multipaths.conf"));
            JsonNode node = root.path("test");
            Iterator<JsonNode> iter = node.iterator();
            while (iter.hasNext()) {
                JsonNode next = iter.next();
                System.out.println("erase the match line." + next.get("volume"));
                if (next.get("volume").asLong() == volumeId) {
                    System.out.println("erase the match line.******************");
                    iter.remove();
                }
            }

            OutputStream outputStream = new FileOutputStream(new File("/home/test/multipaths.conf"));
            objMap.writeValue(outputStream, root);
        } catch (Exception ex) {
            System.out.println("error to read config file.");
            return true;
        }
        return false;
    }