flask框架，Method Not Allowed，code500

flask获取错误，怎么修改呀

@app.route('/')
def hello_world():
    return 'Hello World!'


@app.route("/login", methods=["POST"])
def login():
    """登录"""
    code, msg = 200, "success"
    username = request.json.get("username")
    password = request.json.get("password")
    if not username or not password:
        code, msg = 500, "用户名或者密码不能为空"
    if not User.query.filter_by(username=username, password=password).first():
        code, msg = 500, "密码错误"
    return jsonify({"msg": msg, "code": code})

改了一下代码，又显示code500

@app.route("/login", methods=["GET","POST"])
def login():
    """登录"""
    code, msg = 200, "success"
    if request.method == "GET":
        username = request.args.get("username")
        password = request.args.get("password")
    if request.method == "POST":
        username = request.json.get("username")
        password = request.json.get("password")
    if not username or not password:
        code, msg = 500, "用户名或者密码不能为空"
    if not User.query.filter_by(username=username, password=password).first():
        code, msg = 500, "密码错误"
    return jsonify({"msg": msg, "code": code})

code500通常是服务器的错误，检查服务器代码，以及你参数的传递。