DubboFilter 使用

前言

项目中使用了dubbo,想实现拦截的功能，查看源码对dubbo-filter 做下了解

dubbo-filter-validation 源码查看

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/**
 * ValidationFilter
 */
@Activate(group = {Constants.CONSUMER, Constants.PROVIDER}, value = Constants.VALIDATION_KEY, order = 10000)
public class ValidationFilter implements Filter {

    private Validation validation;

    public void setValidation(Validation validation) {
        this.validation = validation;
    }

    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
        if (validation != null && !invocation.getMethodName().startsWith("$")
                && ConfigUtils.isNotEmpty(invoker.getUrl().getMethodParameter(invocation.getMethodName(), Constants.VALIDATION_KEY))) {
            try {
                Validator validator = validation.getValidator(invoker.getUrl());
                if (validator != null) {
                    validator.validate(invocation.getMethodName(), invocation.getParameterTypes(), invocation.getArguments());
                }
            } catch (RpcException e) {
                throw e;
            } catch (Throwable t) {
                return new RpcResult(t);
            }
        }
        return invoker.invoke(invocation);
    }

}

ValidationFilter 类继承Filter接口， 重写 invoke方法对调用方法参数进行拦截,每个Filter都要加上@Activate注解用于激活，group当其中一个组匹配时，激活当前扩展，order为Filter排序，可选参数。

dubbo-filter-validation配置

配置在META-INF/dubbo/internal/com.alibaba.dubbo.rpc.filter 文件
文件内容
validation=com.alibaba.dubbo.validation.filter.ValidationFilter

dubbo-filter-exception 项目中使用

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@Activate(group = Constants.PROVIDER)
public class DubboFilter implements Filter {

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

    @Override
    public Result invoke(Invoker<?> invoker, Invocation invocation) {
        logger.info("#############DubboFilter start###############" );
        Result result  = invoker.invoke(invocation);
        Throwable exception = result.getException();
        if (exception != null) {
            logger.error("dubbo " + invocation.getMethodName()+" error-->" , exception);
            result = new RpcResult(Result.error("请求异常拦截", "-1"));
        }
        logger.info("#############DubboFilter end###############" );
        return result;
    }
}

dubbo-filter-exception 配置

配置在META-INF/dubbo/com.alibaba.dubbo.rpc.filter 文件
文件内容
dubboFilter=com.xx.xx.xx.filter.DubboFilter

运行结果

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[10-11 13:37:31.031] [WARN] [cat] Cat is lazy initialized!
this app is start
{"message":"请求异常拦截","result":null,"status":false,"statusCode":"-1"}

总结

可以通过filter 对接口请求、返回、异常 全局进行拦截和过滤。