【RPC框架探索】（一）ICE框架的探索

【1】基于Linux CentOS-7的安装

cd /etc/yum.repos.dsudo 
wget https://zeroc.com/download/rpm/zeroc-ice-el7.reposudo 
yum install ice-all-runtime ice-all-devel

【2】编写一个基本的slice，保存为Printer.ice

module Demo {
    interface Printer {
        void printString(string s);
    };
};

编译slice

$ mkdir generated
$ slice2java --output-dir generated Printer.ice

编写一个基本实现

public class PrinterI extends Demo._PrinterDisp {
    public void
    printString(String s, Ice.Current current)
    {
        System.out.println(s);
    }
}

【2】编写Server代码

public class Server {
    public static void
    main(String[] args)
    {
        int status = 0;
        Ice.Communicator ic = null;
        try {
            ic = Ice.Util.initialize(args);
            Ice.ObjectAdapter adapter =
                ic.createObjectAdapterWithEndpoints("SimplePrinterAdapter", "default -p 10000");
            Ice.Object object = new PrinterI();
            adapter.add(object, ic.stringToIdentity("SimplePrinter"));
            adapter.activate();
            ic.waitForShutdown();
        } catch (Ice.LocalException e) {
            e.printStackTrace();
            status = 1;
        } catch (Exception e) {
            System.err.println(e.getMessage());
            status = 1;
        }
        if (ic != null) {
            // Clean up
            //
            try {
                ic.destroy();
            } catch (Exception e) {
                System.err.println(e.getMessage());
                status = 1;
            }
        }
        System.exit(status);
    }
}

编译代码

$ mkdir classes
$ javac -d classes -classpath classes:/usr/share/java/ice.jar \
Server.java PrinterI.java generated/Demo/*.java

这里注意想一下ice.jar的jar的位置，一定要是正确的位置

【3】编写Client代码

public class Client {
    public static void
    main(String[] args)
    {
        int status = 0;
        Ice.Communicator ic = null;
        try {
            ic = Ice.Util.initialize(args);
            Ice.ObjectPrx base = ic.stringToProxy("SimplePrinter:default -p 10000");
            Demo.PrinterPrx printer = Demo.PrinterPrxHelper.checkedCast(base);
            if (printer == null)
                throw new Error("Invalid proxy");

            printer.printString("Hello World!");
        } catch (Ice.LocalException e) {
            e.printStackTrace();
            status = 1;
        } catch (Exception e) {
            System.err.println(e.getMessage());
            status = 1;
        }
        if (ic != null) {
            // Clean up
            //
            try {
                ic.destroy();
            } catch (Exception e) {
                System.err.println(e.getMessage());
                status = 1;
            }
        }
        System.exit(status);
    }
}

编译Client

$ javac -d classes -classpath classes:/usr/share/java/ice.jar \
Client.java PrinterI.java generated/Demo/*.java

【4】执行Server和Client

cd classes
java Server &
java Client &

出现错误

Error: A JNI error has occurred, please check your installation and try again

出现这个错误，检查发现CLASSPATH中没有设置ice.jar，搜索系统ice.jar，发现在/usr/share/java/ice.jar，将其添加到classpath中，问题解决，可以使用下面的脚本setenv.sh

#! /bin/bash

JAVA_HOME=/usr/java/jdk1.8.0_131
CLASSPATH=.:$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar:/usr/share/java/ice.jar
PATH=$JAVA_HOME/bin:$PATH
export JAVA_HOME CLASSPATH PATH

执行source setenv.sh，设置好相关变量

java Server &
java Client &

出现结果

Hello World!

调用成功
【5】使用python客户端调用java的服务端
安装pip和ice-python

sudo yum install python-pip
pip install zeroc-ice

出现错误

#include 
compilation terminated.
error: command 'gcc' failed with exit status 1

安装python开发环境解决

sudo yum install python-devl

出现错误

#include 
compilation terminated.
error: command 'gcc' failed with exit status 1

安装bzip2开发库

sudo yum install bzip2-devel

编译python版的ice文件

slice2py Printer.ice

编写python的Client.py

import sys, traceback, Ice
import Demo

status = 0
ic = None
try:
    ic = Ice.initialize(sys.argv)
    base = ic.stringToProxy("SimplePrinter:default -p 10000")
    printer = Demo.PrinterPrx.checkedCast(base)
    if not printer:
        raise RuntimeError("Invalid proxy")

    printer.printString("Hello World!")
except:
    traceback.print_exc()
    status = 1

if ic:
    # Clean up
    try:
        ic.destroy()
    except:
        traceback.print_exc()
        status = 1

sys.exit(status)

然后直接调用

python Client.py

结果

Hello World!