JSONDecodeError at /update_item/期望值:第1行，第1列(字符0)

import json

try:
    data = json.loads(json_string)
except json.JSONDecodeError as e:
    print(f"JSON解析错误: {e}")
    # 可以在这里进行错误处理，比如返回一个默认值或者错误信息
    data = {}

if not isinstance(json_string, str) or not json_string:
    print("无效的输入数据")
    data = {}
else:
    try:
        data = json.loads(json_string)
    except json.JSONDecodeError as e:
        print(f"JSON解析错误: {e}")
        data = {}

from flask import Flask, request, jsonify
import json

app = Flask(__name__)

@app.route('/update_item', methods=['POST'])
def update_item():
    json_string = request.get_data(as_text=True)
    
    try:
        data = json.loads(json_string)
        # 处理解析后的数据
        return jsonify(success=True, data=data)
    except json.JSONDecodeError as e:
        return jsonify(success=False, error=str(e)), 400

if __name__ == '__main__':
    app.run(debug=True)