Java RPC中的代理 (Client)

调用图

Client实现

远程接口定义

public interface XxxApi {
    boolean remoteMethod();
}

Proxy工厂

public final class ProxyFactory {

    @SuppressWarnings("unchecked")
    public <T> T getProxy(Class<T> clz, InvocationHandler invocationHandler) {
        return (T) Proxy.newProxyInstance(this.getClass().getClassLoader(), new Class[] {clz}, invocationHandler);
    }

}

函数返回值基本类型的默认值

public final class PrimitiveDefault {
    private static boolean defaultBoolean;
    private static char defaultChar;
    private static byte defaultByte;
    private static short defaultShort;
    private static int defaultInt;
    private static long defaultLong;
    private static float defaultFloat;
    private static double defaultDouble;
    private static Map<Class<?>, Object> primitiveValues = new HashMap<Class<?>, Object>();

    static {
        primitiveValues.put(boolean.class, defaultBoolean);
        primitiveValues.put(char.class, defaultChar);
        primitiveValues.put(byte.class, defaultByte);
        primitiveValues.put(short.class, defaultShort);
        primitiveValues.put(int.class, defaultInt);
        primitiveValues.put(long.class, defaultLong);
        primitiveValues.put(float.class, defaultFloat);
        primitiveValues.put(double.class, defaultDouble);
    }

    public static Object getDefaultReturnValue(Class<?> returnType) {
        return primitiveValues.get(returnType);
    }
}

Client调用

public final class Runner {

    private static final Logger logger = LoggerFactory.getLogger(Runner.class);

    public static void main(String[] ignore) {
        ProxyFactory proxyFactory = new ProxyFactory();

        XxxApi xxxApi = proxyFactory.getProxy(XxxApi.class, (proxy, method, args) -> {
            // 判断method是否定义过 todo
            logger.info("{} {}", method, args);
            // 产生1个默认值
            Class<?> returnType = method.getReturnType();
            if (returnType != null && returnType.isPrimitive()) {
                return PrimitiveDefault.getDefaultReturnValue(returnType);
            }
            return null;
        });

        xxxApi.remoteMethod();
    }

}