Thrift.Thrift.TApplicationExceptionUNKNOWN_METHOD：方法未被支持

Thrift.TApplicationException.UNKNOWN_METHOD is an exception that is thrown when a client attempts to invoke a method that is not supported by the server. This exception is specific to the Thrift framework, which is used for efficient and cross-language communication between services.

Here is an example to illustrate how this exception can occur:

1. Define the Thrift service and its methods:

service CalculatorService {
    i32 add(1:i32 num1, 2:i32 num2),
    i32 subtract(1:i32 num1, 2:i32 num2)
}

2. Implement the CalculatorService in the server application:

class CalculatorHandler:
    def add(self, num1, num2):
        return num1 + num2

server = TServer.TThreadPoolServer(
    CalculatorService.Processor(CalculatorHandler()),
    TSocket.TServerSocket(port=9090),
    TTransport.TBufferedTransportFactory(),
    TBinaryProtocol.TBinaryProtocolFactory(),
)

server.serve()

3. Write a client application and attempt to invoke a method that is not supported:

try:
    # Create a Thrift client
    transport = TSocket.TSocket('localhost', 9090)
    transport.open()
    protocol = TBinaryProtocol.TBinaryProtocol(transport)
    client = CalculatorService.Client(protocol)

    # Invoke a method that is not supported
    result = client.multiply(2, 3)
    print(f"Result: {result}")

    transport.close()

except Thrift.TApplicationException as ex:
    print(f"Thrift error: {ex.message}")

In this example, the server only supports the "add" and "subtract" methods. The client attempts to invoke the "multiply" method, which is not supported by the server. As a result, the server raises the Thrift.TApplicationException.UNKNOWN_METHOD exception, and the client catches and handles this exception.

The output of the client application will be:

Thrift error: Unknown method multiply

This exception can be useful in debugging and error handling, as it provides information about the unsupported method and helps identify issues in the client-server communication.