try { // 获取当前日期 LocalDate currentDate = LocalDate.now(); // 定义日期格式 DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd"); // 转换为指定格式的字符串 String dateString = currentDate.format(formatter); // 构建URL对象 URL url = new URL(API_BASE_URL + "?begin=" + dateString + "&Methodname=" + URLEncoder.encode(str, "UTF-8")); // 创建HttpURLConnection对象 HttpURLConnection connection = (HttpURLConnection) url.openConnection(); // 设置请求方法为GET connection.setRequestMethod("GET"); // 设置Basic认证信息 String auth = API_USERNAME + ":" + API_PASSWORD; byte[] authBytes = auth.getBytes(StandardCharsets.UTF_8); String authHeaderValue = "Basic " + Base64.getEncoder().encodeToString(authBytes); connection.setRequestProperty("Authorization", authHeaderValue); // 设置字符编码为UTF-8 connection.setRequestProperty("Accept-Charset", "UTF-8"); // 发送请求 int responseCode = connection.getResponseCode(); // 读取响应数据 BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8)); StringBuilder responseBuilder = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { responseBuilder.append(line); } String response = responseBuilder.toString(); // 关闭连接 connection.disconnect(); // 返回响应数据 ObjectMapper objectMapper = new ObjectMapper(); JsonNode rootNode = objectMapper.readTree(response); String ls = rootNode.get("data").get(0).toString(); return ls; } catch (Exception e) { e.printStackTrace(); return "Error: " + e.getMessage(); }其中ls的值是"{\"ls\":\"603\"}"，修改一下，ls只需要”603“

在获取到 `ls` 的值时，可以使用 `JsonNode` 的 `get()` 方法获取到 `ls` 字段对应的值，然后使用 `String` 的 `replaceAll()` 方法去除多余的字符，具体修改如下：

try {
    // 获取当前日期
    LocalDate currentDate = LocalDate.now();
    // 定义日期格式
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    // 转换为指定格式的字符串
    String dateString = currentDate.format(formatter);
    // 构建URL对象
    URL url = new URL(API_BASE_URL + "?begin=" + dateString + "&Methodname=" + URLEncoder.encode(str, "UTF-8"));
    // 创建HttpURLConnection对象
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    // 设置请求方法为GET
    connection.setRequestMethod("GET");
    // 设置Basic认证信息
    String auth = API_USERNAME + ":" + API_PASSWORD;
    byte[] authBytes = auth.getBytes(StandardCharsets.UTF_8);
    String authHeaderValue = "Basic " + Base64.getEncoder().encodeToString(authBytes);
    connection.setRequestProperty("Authorization", authHeaderValue);
    // 设置字符编码为UTF-8
    connection.setRequestProperty("Accept-Charset", "UTF-8");
    // 发送请求
    int responseCode = connection.getResponseCode();
    // 读取响应数据
    BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8));
    StringBuilder responseBuilder = new StringBuilder();
    String line;
    while ((line = reader.readLine()) != null) {
        responseBuilder.append(line);
    }
    String response = responseBuilder.toString();
    // 关闭连接
    connection.disconnect();
    // 返回响应数据
    ObjectMapper objectMapper = new ObjectMapper();
    JsonNode rootNode = objectMapper.readTree(response);
    String ls = rootNode.get("data").get(0).get("ls").asText().replaceAll("[^\u4e00-\u9fa5^\\d]", "");
    return ls;
} catch (Exception e) {
    e.printStackTrace();
    return "Error: " + e.getMessage();
}

在上述代码中，使用了 `JsonNode` 的 `asText()` 方法将 `ls` 的值转化为字符串类型，然后使用 `replaceAll()` 方法去除多余字符，只保留数字和中文。