java版spring cloud微服務架構b2b2c--Feign自定義註解翻譯器

一 、新建自定義註解MyUrl瞭解springcloud架構能夠加求求：三五三六二四七二五九

package org.crazyit.cloud.contract;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

//這個註解只能定義方法
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface MyUrl {
    //爲註解配置兩個屬性
    String url();
    String method();
}

2、 新建接口，使用MyUrl註解

package org.crazyit.cloud.contract;

public interface ContractClient {

    @MyUrl(url = "/hello", method = "GET")
    public String hello();
}

3、 定義註解翻譯器

package org.crazyit.cloud.contract;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;

import feign.Contract.BaseContract;
import feign.MethodMetadata;

public class MyContract extends BaseContract {

    @Override
    protected void processAnnotationOnClass(MethodMetadata data, Class<?> clz) {
        // 處理類級別註解

    }

    @Override
    protected void processAnnotationOnMethod(MethodMetadata data,
            Annotation annotation, Method method) {
        // 註解是MyUrl類型的，才處理
        if(MyUrl.class.isInstance(annotation)) {
            MyUrl myUrl = method.getAnnotation(MyUrl.class);
            String url = myUrl.url();
            String httpMethod = myUrl.method();
            data.template().method(httpMethod);
            data.template().append(url);
        }
    }

    @Override
    protected boolean processAnnotationsOnParameter(MethodMetadata data,
            Annotation[] annotations, int paramIndex) {
        // 處理參數級別註解
        return false;
    }

}

4、 測試類

package org.crazyit.cloud.contract;

import org.crazyit.cloud.jaxrs.RsClient;

import feign.Feign;
import feign.jaxrs.JAXRSContract;

public class ContractMain {

    public static void main(String[] args) {
        ContractClient client = Feign.builder()
                .contract(new MyContract())
                .target(ContractClient.class,
                "http://localhost:8080");
        String result = client.hello();
        System.out.println(result);
    }

}