标量消息字段可以具有以下类型之一 - 该表显示.proto文件中指定的类型，以及自动生成的类中的相应类型：
| .proto Type | Notes | C++ Type | Java Type | Python Type[2] | Go Type |
|---|---|---|---|---|---|
| double | 固定8字节长度 | double | double | float | float64 |
| float | 固定4字节长度 | float | float | float | float32 |
| int32 | 可变长度编码。对负数编码低效，如果字段可能是负数，用sint32代替 | int32 | int | int | int32 |
| int64 | 可变长度编码。对负数编码低效，如果字段可能是负数，用sint64代替 | int64 | long | int/long[3] | int64 |
| uint32 | 可变长度编码，无符号整数 | uint32 | int[1] | int/long[3] | uint32 |
| uint64 | 可变长度编码，无符号整数 | uint64 | long[1] | int/long[3] | uint64 |
| sint32 | 可变长度编码。有符号整数。 These more efficiently encode negative numbers than regular int32s. | int32 | int | int | int32 |
| sint64 | 可变长度编码。有符号整数。These more efficiently encode negative numbers than regular int64s. | int64 | long | int/long[3] | int64 |
| fixed32 | 固定4字节长度，无符号整数。 More efficient than uint32 if values are often greater than 228. | uint32 | int[1] | int/long[3] | uint32 |
| fixed64 | 固定8字节长度，无符号整数。 More efficient than uint64 if values are often greater than 256. | uint64 | long[1] | int/long[3] | uint64 |
| sfixed32 | 固定4字节长度，有符号整数 | int32 | int | int | int32 |
| sfixed64 | 固定8字节长度，有符号整数 | int64 | long | int/long[3] | int64 |
| bool | bool | boolean | bool | bool | |
| string | UTF-8 encoded or 7-bit ASCII text. | string | String | str/unicode[4] | string |
| bytes | 包含任意字节序列 | string | ByteString | str | []byte |