Netty实现远程调用RPC功能

添加依赖

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.2.Final</version>
</dependency>

<dependency>
    <groupId>org.reflections</groupId>
    <artifactId>reflections</artifactId>
    <version>0.9.10</version>
</dependency>

组织架构

服务端

封装类信息

public class ClassInfo implements Serializable {

    private static final long serialVersionUID = 1L;

    private String className;  //类名
    private String methodName;//方法名
    private Class<?>[] types; //参数类型
    private Object[] objects;//参数列表

    public String getClassName() {
        return className;
    }

    public void setClassName(String className) {
        this.className = className;
    }

    public String getMethodName() {
        return methodName;
    }

    public void setMethodName(String methodName) {
        this.methodName = methodName;
    }

    public Class<?>[] getTypes() {
        return types;
    }

    public void setTypes(Class<?>[] types) {
        this.types = types;
    }

    public Object[] getObjects() {
        return objects;
    }

    public void setObjects(Object[] objects) {
        this.objects = objects;
    }
}

服务端网络处理服务器

public class NettyRPCServer {
    private int port;
    public NettyRPCServer(int port) {
        this.port = port;
    }

    public void start() {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    .localAddress(port).childHandler(
                            new ChannelInitializer<SocketChannel>() {
                                @Override
                                protected void initChannel(SocketChannel ch) throws Exception {
                                    ChannelPipeline pipeline = ch.pipeline();
                                    //编码器
                                    pipeline.addLast("encoder", new ObjectEncoder());
                                    //解码器
                                    pipeline.addLast("decoder", new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.cacheDisabled(null)));
                                    //服务器端业务处理类
                                    pipeline.addLast(new InvokeHandler());
                                }
                            });
            ChannelFuture future = serverBootstrap.bind(port).sync();
            System.out.println("......server is ready......");
            future.channel().closeFuture().sync();
        } catch (Exception e) {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        new NettyRPCServer(9999).start();
    }
}

服务器端业务处理类

public class InvokeHandler extends ChannelInboundHandlerAdapter {
    //得到某接口下某个实现类的名字
    private String getImplClassName(ClassInfo classInfo) throws Exception{
        //服务方接口和实现类所在的包路径
        String interfacePath="com.lyz.server";
        int lastDot = classInfo.getClassName().lastIndexOf(".");
        String interfaceName=classInfo.getClassName().substring(lastDot);
        Class superClass=Class.forName(interfacePath+interfaceName);
        Reflections reflections = new Reflections(interfacePath);
        //得到某接口下的所有实现类
        Set<Class> ImplClassSet=reflections.getSubTypesOf(superClass);
        if(ImplClassSet.size()==0){
            System.out.println("未找到实现类");
            return null;
        }else if(ImplClassSet.size()>1){
            System.out.println("找到多个实现类，未明确使用哪一个");
            return null;
        }else {
            //把集合转换为数组
            Class[] classes=ImplClassSet.toArray(new Class[0]);
            return classes[0].getName(); //得到实现类的名字
        }
    }

    @Override  //读取客户端发来的数据并通过反射调用实现类的方法
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ClassInfo classInfo = (ClassInfo) msg;
        System.out.println(classInfo);
        Object clazz = Class.forName(getImplClassName(classInfo)).newInstance();
        Method method = clazz.getClass().getMethod(classInfo.getMethodName(), classInfo.getTypes());
        //通过反射调用实现类的方法
        Object result = method.invoke(clazz, classInfo.getObjects());
        ctx.writeAndFlush(result);
    }
}

服务端接口及实现类

// 无参接口
public interface HelloNetty {
    String hello();
}

// 实现类
public class HelloNettyImpl implements HelloNetty {
    @Override
    public String hello() {
        return "hello,netty";
    }
}

// 带参接口
public interface HelloRPC {
    String hello(String name);
}

// 实现类
public class HelloRPCImpl implements HelloRPC {
    @Override
    public String hello(String name) {
        return "hello," + name;
    }
}

客户端

代理类

public class NettyRPCProxy {
    //根据接口创建代理对象
    public static Object create(Class target) {
        return Proxy.newProxyInstance(target.getClassLoader(), new Class[]{target}, new InvocationHandler() {
            @Override
            public Object invoke(Object proxy, Method method, Object[] args)
                    throws Throwable {
                //封装ClassInfo
                ClassInfo classInfo = new ClassInfo();
                classInfo.setClassName(target.getName());
                classInfo.setMethodName(method.getName());
                classInfo.setObjects(args);
                classInfo.setTypes(method.getParameterTypes());

                //开始用Netty发送数据
                EventLoopGroup group = new NioEventLoopGroup();
                ResultHandler resultHandler = new ResultHandler();
                try {
                    Bootstrap b = new Bootstrap();
                    b.group(group)
                            .channel(NioSocketChannel.class)
                            .handler(new ChannelInitializer<SocketChannel>() {
                                @Override
                                public void initChannel(SocketChannel ch) throws Exception {
                                    ChannelPipeline pipeline = ch.pipeline();
                                    //编码器
                                    pipeline.addLast("encoder", new ObjectEncoder());
                                    //解码器  构造方法第一个参数设置二进制数据的最大字节数  第二个参数设置具体使用哪个类解析器
                                    pipeline.addLast("decoder", new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.cacheDisabled(null)));
                                    //客户端业务处理类
                                    pipeline.addLast("handler", resultHandler);
                                }
                            });
                    ChannelFuture future = b.connect("127.0.0.1", 9999).sync();
                    future.channel().writeAndFlush(classInfo).sync();
                    future.channel().closeFuture().sync();
                } finally {
                    group.shutdownGracefully();
                }
                return resultHandler.getResponse();
            }
        });
    }
}

客户端业务处理类

public class ResultHandler extends ChannelInboundHandlerAdapter {

    private Object response;
    public Object getResponse() {
        return response;
    }

    @Override //读取服务器端返回的数据(远程调用的结果)
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        response = msg;
        ctx.close();
    }
}

客户端接口

// 无参接口
public interface HelloNetty {
    String hello();
}

// 带参接口
public interface HelloRPC {
    String hello(String name);
}

测试类 服务调用方

public class TestNettyRPC {
    public static void main(String [] args){

        //第1次远程调用
        HelloNetty helloNetty=(HelloNetty) NettyRPCProxy.create(HelloNetty.class);
        System.out.println(helloNetty.hello());

        //第2次远程调用
        HelloRPC helloRPC =  (HelloRPC) NettyRPCProxy.create(HelloRPC.class);
        System.out.println(helloRPC.hello("RPC"));

    }
}

输出结果

服务端

......server is ready......
com.lyz.serverStub.ClassInfo@2b894733
com.lyz.serverStub.ClassInfo@167bfa9

客户端

hello,netty
hello,RPC

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