用Java开发gRPC服务的例子分析

Posted on 2016-04-20 11:03 蝈蝈俊阅读(10235) 评论(0) 编辑收藏举报

本文的代码例子来自：https://github.com/grpc/grpc-java

定义服务

这一步与其他语言完全一样，需要定义gRPC的服务、方法、request和response的类型。

完整的proto定义代码在：grpc-java/examples/src/main/proto/route_guide.proto

在proto中，下面几个定义是为我们生成 Java 类所特有的定义。

option java_multiple_files = true;
option java_package = "io.grpc.examples.routeguide";
option java_outer_classname = "RouteGuideProto";

如果在 .proto 文件中没有显示的 java_package 参数，
那么就会使用缺省的 proto 包（通过 "package" 关键字指定）。但是，因为 proto 包一般不是以域名
翻转的格式命名，所以它不是好的 Java 包。如果我们用其它语言通过 .proto 文件生成代码，java_package 是不起任何作用的。

定义四种方法（简单RPC、服务器端流式RPC、客户端流式RPC、双向流式RPC）的细节就不在重复，跟其他语言完全一样。

生成客户端和服务器端代码

从 .proto 的服务定义中生成 gRPC 客户端和服务器端的接口。我们通过 protocol buffer 的编译器 protoc 以及一个特殊的 gRPC Java 插件来完成。

这个工具请在 https://github.com/google/protobuf/releases 这里下载。

具体编译的方法，请参考： http://www.cnblogs.com/ghj1976/p/5391205.html

完整的生产内容如下：

编译执行客户端和服务器代码

https://github.com/grpc/grpc-java 例子的编译方法在：

https://github.com/grpc/grpc-java/blob/master/examples/README.md

编译例子，我们需要在 examples 目录运行下面命令:

$ ../gradlew installDist -PskipCodegen=true

执行的结果如下：

pwd
/Users/ghj1976/project/github/grpc/grpc-java/examples
localhost:examples ghj1976$
localhost:examples ghj1976$ ls
README.md android build.gradle src
localhost:examples ghj1976$
localhost:examples ghj1976$ ../gradlew installDist -PskipCodegen=true
Downloading https://services.gradle.org/distributions/gradle-2.11-bin.zip
........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
Unzipping /Users/ghj1976/.gradle/wrapper/dists/gradle-2.11-bin/452syho4l32rlk2s8ivdjogs8/gradle-2.11-bin.zip to /Users/ghj1976/.gradle/wrapper/dists/gradle-2.11-bin/452syho4l32rlk2s8ivdjogs8
Set executable permissions for: /Users/ghj1976/.gradle/wrapper/dists/gradle-2.11-bin/452syho4l32rlk2s8ivdjogs8/gradle-2.11/bin/gradle
*** Skipping the build of codegen and compilation of proto files because skipCodegen=true
Download https://repo1.maven.org/maven2/com/google/gradle/osdetector-gradle-plugin/1.4.0/osdetector-gradle-plugin-1.4.0.pom
Download https://repo1.maven.org/maven2/kr/motd/maven/os-maven-plugin/1.4.0.Final/os-maven-plugin-1.4.0.Final.pom
Download https://repo1.maven.org/maven2/com/google/gradle/osdetector-gradle-plugin/1.4.0/osdetector-gradle-plugin-1.4.0.jar
Download https://repo1.maven.org/maven2/kr/motd/maven/os-maven-plugin/1.4.0.Final/os-maven-plugin-1.4.0.Final.jar
Download https://repo1.maven.org/maven2/org/apache/maven/maven-plugin-api/3.2.1/maven-plugin-api-3.2.1.jar
Download https://repo1.maven.org/maven2/org/apache/maven/maven-model/3.2.1/maven-model-3.2.1.jar
Download https://repo1.maven.org/maven2/org/apache/maven/maven-artifact/3.2.1/maven-artifact-3.2.1.jar
Download https://repo1.maven.org/maven2/org/codehaus/plexus/plexus-classworlds/2.4/plexus-classworlds-2.4.jar
Download https://repo1.maven.org/maven2/org/kt3k/gradle/plugin/coveralls-gradle-plugin/2.0.1/coveralls-gradle-plugin-2.0.1.pom
Download https://repo1.maven.org/maven2/org/apache/httpcomponents/httpmime/4.3/httpmime-4.3.pom
Download https://repo1.maven.org/maven2/org/apache/httpcomponents/httpcomponents-client/4.3/httpcomponents-client-4.3.pom
Download https://repo1.maven.org/maven2/org/apache/httpcomponents/project/7/project-7.pom
Download https://repo1.maven.org/maven2/org/codehaus/groovy/modules/http-builder/http-builder/0.7.1/http-builder-0.7.1.pom
Download https://repo1.maven.org/maven2/org/apache/httpcomponents/httpclient/4.3/httpclient-4.3.pom
Download https://repo1.maven.org/maven2/net/sf/json-lib/json-lib/2.3/json-lib-2.3.pom
Download https://repo1.maven.org/maven2/net/sourceforge/nekohtml/nekohtml/1.9.16/nekohtml-1.9.16.pom
Download https://repo1.maven.org/maven2/xml-resolver/xml-resolver/1.2/xml-resolver-1.2.pom
Download https://repo1.maven.org/maven2/commons-beanutils/commons-beanutils/1.8.0/commons-beanutils-1.8.0.pom
Download https://repo1.maven.org/maven2/net/sf/ezmorph/ezmorph/1.0.6/ezmorph-1.0.6.pom
Download https://repo1.maven.org/maven2/org/apache/httpcomponents/httpcore/4.3/httpcore-4.3.pom
Download https://repo1.maven.org/maven2/org/apache/httpcomponents/httpcomponents-core/4.3/httpcomponents-core-4.3.pom
Download https://repo1.maven.org/maven2/org/kt3k/gradle/plugin/coveralls-gradle-plugin/2.0.1/coveralls-gradle-plugin-2.0.1.jar
Download https://repo1.maven.org/maven2/org/apache/httpcomponents/httpmime/4.3/httpmime-4.3.jar
Download https://repo1.maven.org/maven2/org/codehaus/groovy/modules/http-builder/http-builder/0.7.1/http-builder-0.7.1.jar
Download https://repo1.maven.org/maven2/org/apache/httpcomponents/httpclient/4.3/httpclient-4.3.jar
Download https://repo1.maven.org/maven2/net/sf/json-lib/json-lib/2.3/json-lib-2.3-jdk15.jar
Download https://repo1.maven.org/maven2/net/sourceforge/nekohtml/nekohtml/1.9.16/nekohtml-1.9.16.jar
Download https://repo1.maven.org/maven2/xml-resolver/xml-resolver/1.2/xml-resolver-1.2.jar
Download https://repo1.maven.org/maven2/commons-beanutils/commons-beanutils/1.8.0/commons-beanutils-1.8.0.jar
Download https://repo1.maven.org/maven2/net/sf/ezmorph/ezmorph/1.0.6/ezmorph-1.0.6.jar
Download https://repo1.maven.org/maven2/org/apache/httpcomponents/httpcore/4.3/httpcore-4.3.jar
Download https://plugins.gradle.org/m2/be/insaneprogramming/gradle/animalsniffer-gradle-plugin/1.4.0/animalsniffer-gradle-plugin-1.4.0.pom

FAILURE: Build failed with an exception.

* Where:
Build file '/Users/ghj1976/project/github/grpc/grpc-java/all/build.gradle' line: 32

* What went wrong:
A problem occurred evaluating project ':grpc-all'.
> A problem occurred configuring project ':grpc-auth'.
   > Could not resolve all dependencies for configuration ':grpc-auth:classpath'.
      > Could not download animalsniffer-gradle-plugin.jar (be.insaneprogramming.gradle:animalsniffer-gradle-plugin:1.4.0)
         > Could not get resource 'https://plugins.gradle.org/m2/be/insaneprogramming/gradle/animalsniffer-gradle-plugin/1.4.0/animalsniffer-gradle-plugin-1.4.0.jar'.
            > Could not GET 'https://plugins.gradle.org/m2/be/insaneprogramming/gradle/animalsniffer-gradle-plugin/1.4.0/animalsniffer-gradle-plugin-1.4.0.jar'.
               > gradleware-plugins.s3.amazonaws.com:443 failed to respond

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 16 mins 47.903 secs
localhost:examples ghj1976$

这个build错误，是因为下载https://plugins.gradle.org时需要FQ才能下载。设置FQ后，设置本机代理：

export http_proxy=http://127.0.0.1:8787

既可以正常下载了。

BUILD SUCCESSFUL

Total time: 1 mins 44.412 secs

This build could be faster, please consider using the Gradle Daemon: https://docs.gradle.org/2.11/userguide/gradle_daemon.html
localhost:examples ghj1976$

命令执行完毕后，会在 build/install/grpc-examples/bin/ 目录下产生编译好的文件。

运行服务器端：

$ ./build/install/grpc-examples/bin/hello-world-server

在另外一个终端窗口运行客户端：

$ ./build/install/grpc-examples/bin/hello-world-client

参考资料：

http://doc.oschina.net/grpc?t=60134

http://www.grpc.io/docs/tutorials/basic/java.html

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用Java开发gRPC服务的例子分析

定义服务

生成客户端和服务器端代码

编译执行客户端和服务器代码