Protocol Buffers - Google's data interchange format (grpc依赖)
https://developers.google.com/protocol-buffers/
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180 lines
6.1 KiB
180 lines
6.1 KiB
# Protocol Buffers - Google's data interchange format |
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Copyright 2008 Google Inc. |
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https://developers.google.com/protocol-buffers/ |
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## Use Java Protocol Buffers |
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To use protobuf in Java, first obtain the protocol compiler (a.k.a., protoc, |
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see instructions in the toplevel [README.md](../README.md)) and use it to |
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generate Java code for your .proto files: |
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$ protoc --java_out=${OUTPUT_DIR} path/to/your/proto/file |
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Include the generated Java files in your project and add a dependency on the |
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protobuf Java runtime. |
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### Maven |
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If you are using Maven, use the following: |
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```xml |
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<dependency> |
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<groupId>com.google.protobuf</groupId> |
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<artifactId>protobuf-java</artifactId> |
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<version>3.9.1</version> |
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</dependency> |
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``` |
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Make sure the version number of the runtime matches (or is newer than) the |
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version number of the protoc. |
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If you want to use features like protobuf JsonFormat, add a dependency on the |
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protobuf-java-util package: |
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```xml |
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<dependency> |
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<groupId>com.google.protobuf</groupId> |
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<artifactId>protobuf-java-util</artifactId> |
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<version>3.9.1</version> |
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</dependency> |
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``` |
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### Gradle |
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If you are using Gradle, add the following to your `build.gradle` file's dependencies: |
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``` |
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compile 'com.google.protobuf:protobuf-java:3.9.1' |
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``` |
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Again, be sure to check that the version number maches (or is newer than) the version number of protoc that you are using. |
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### Use Java Protocol Buffers on Android |
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For Android users, it's recommended to use protobuf Java Lite runtime because |
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of its smaller code size. Java Lite runtime also works better with Proguard |
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because it doesn't rely on Java reflection and is optimized to allow as much |
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code stripping as possible. You can following these [instructions to use Java |
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Lite runtime](lite.md). |
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### Use Java Protocol Buffers with Bazel |
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Bazel has native build rules to work with protobuf. For Java, you can use the |
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`java_proto_library` rule for server and the `java_lite_proto_library` rule |
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for Android. Check out [our build files examples](../examples/BUILD) to learn |
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how to use them. |
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## Build from Source |
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Most users should follow the instructions above to use protobuf Java runtime. |
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If you are contributing code to protobuf or want to use a protobuf version |
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that hasn't been officially released yet, you can folllow the instructions |
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below to build protobuf from source code. |
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### Build from Source - With Maven |
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1) Install Apache Maven if you don't have it: |
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http://maven.apache.org/ |
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2) Build the C++ code, or obtain a binary distribution of protoc (see |
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the toplevel [README.md](../README.md)). If you install a binary |
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distribution, make sure that it is the same version as this package. |
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If in doubt, run: |
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$ protoc --version |
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You will need to place the protoc executable in ../src. (If you |
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built it yourself, it should already be there.) |
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3) Run the tests: |
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$ mvn test |
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If some tests fail, this library may not work correctly on your |
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system. Continue at your own risk. |
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4) Install the library into your Maven repository: |
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$ mvn install |
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5) If you do not use Maven to manage your own build, you can build a |
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.jar file to use: |
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$ mvn package |
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The .jar will be placed in the "target" directory. |
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The above instructions will install 2 maven artifacts: |
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* protobuf-java: The core Java Protocol Buffers library. Most users only |
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need this artifact. |
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* protobuf-java-util: Utilities to work with protos. It contains JSON support |
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as well as utilities to work with proto3 well-known |
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types. |
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### Build from Source - Without Maven |
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If you would rather not install Maven to build the library, you may |
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follow these instructions instead. Note that these instructions skip |
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running unit tests and only describes how to install the core protobuf |
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library (without the util package). |
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1) Build the C++ code, or obtain a binary distribution of protoc. If |
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you install a binary distribution, make sure that it is the same |
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version as this package. If in doubt, run: |
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$ protoc --version |
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If you built the C++ code without installing, the compiler binary |
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should be located in ../src. |
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2) Invoke protoc to build DescriptorProtos.java: |
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$ protoc --java_out=core/src/main/java -I../src \ |
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../src/google/protobuf/descriptor.proto |
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3) Compile the code in core/src/main/java using whatever means you prefer. |
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4) Install the classes wherever you prefer. |
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## Compatibility Notice |
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* Protobuf minor version releases are backwards-compatible. If your code |
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can build/run against the old version, it's expected to build/run against |
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the new version as well. Both binary compatibility and source compatibility |
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are guaranteed for minor version releases if the user follows the guideline |
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described in this section. |
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* Protobuf major version releases may also be backwards-compatbile with the |
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last release of the previous major version. See the release notice for more |
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details. |
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* APIs marked with the @ExperimentalApi annotation are subject to change. They |
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can be modified in any way, or even removed, at any time. Don't use them if |
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compatibility is needed. If your code is a library itself (i.e. it is used on |
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the CLASSPATH of users outside your own control), you should not use |
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experimental APIs, unless you repackage them (e.g. using ProGuard). |
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* Deprecated non-experimental APIs will be removed two years after the release |
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in which they are first deprecated. You must fix your references before this |
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time. If you don't, any manner of breakage could result (you are not |
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guaranteed a compilation error). |
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* Protobuf message interfaces/classes are designed to be subclassed by protobuf |
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generated code only. Do not subclass these message interfaces/classes |
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yourself. We may add new methods to the message interfaces/classes which will |
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break your own subclasses. |
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* Don't use any method/class that is marked as "used by generated code only". |
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Such methods/classes are subject to change. |
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* Protobuf LITE runtime APIs are not stable yet. They are subject to change even |
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in minor version releases. |
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## Documentation |
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The complete documentation for Protocol Buffers is available via the |
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web at: |
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https://developers.google.com/protocol-buffers/
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