详解Java是如何通过接口来创建代理并进行http请求

import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.annotation.Autowired;

import java.lang.reflect.Proxy;


public class HttpProxyFactoryBean<T> implements FactoryBean<T> {

    
    @Autowired
    private HttpProxyInvocationHandler httpProxyInvocationHandler;

    private Class<T> rpcInterface;

    public HttpProxyFactoryBean(Class<T> rpcInterface){
        this.rpcInterface = rpcInterface;
    }


    @Override
    public T getObject() throws Exception {
        //这里应该放ComputerService接口
        return (T)Proxy.newProxyInstance(rpcInterface.getClassLoader(),new Class[]{rpcInterface} ,httpProxyInvocationHandler);
    }

    @Override
    public Class<?> getObjectType() {
        return rpcInterface;
    }

}

import cn.hutool.http.HttpRequest;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;


@Component
public class HttpProxyInvocationHandler implements InvocationHandler {

    @Value("${proxy.serverUrl}")
    private String serverUrl;

    @Value("${proxy.project}")
    private String serverProject;

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        Class<?> declaringClass = method.getDeclaringClass();
        if (Object.class.equals(declaringClass)) {
            return method.invoke(this, args);
        }

        String methodName = method.getName();
        String name = method.getDeclaringClass().getName();

        //拼接请求地址
        String url = serverUrl + name + "/" + methodName;
//        String url = "http://test:8080/soa/com.rdd.TestService/createActivity";
        HashMap<String, String> paramMap = new HashMap<>();
    
//        String result = HttpRequest.post(url).headerMap(paramMap, true).body("[" + JSONObject.toJSONString(args) + "]").execute().body();
        String result = HttpRequest.post(url).headerMap(paramMap, true).body(JSONObject.toJSONString(args)).execute().body();

        System.out.println(">>>" + url + "的响应结果为:" + result);

        //将响应结果转换为接口方法的返回值类型
        Class<?> returnType = method.getReturnType();
        if (returnType.isPrimitive() || String.class.isAssignableFrom(returnType)) {
            if (returnType == int.class || returnType == Integer.class) {
                return Integer.valueOf(result);
            } else if (returnType == long.class || returnType == Long.class) {
                return Long.valueOf(result);
            }
            return result;
        } else if (Collection.class.isAssignableFrom(returnType)) {
            return JSONArray.parseArray(result, Object.class);
        } else if (Map.class.isAssignableFrom(returnType)) {
            return JSON.parseObject(result, Map.class);
        } else {
            return JSONObject.parseObject(result, returnType);
        }
    }
}

import cn.hutool.core.io.file.FileReader;
import org.apache.commons.lang.StringUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.*;
import org.springframework.context.annotation.PropertySource;
import org.springframework.stereotype.Component;

import java.util.HashSet;
import java.util.List;
import java.util.Set;


@Component
@PropertySource("classpath:application.properties")
public class HttpProxyRegistryPostProcessor implements BeanDefinitionRegistryPostProcessor {

    
    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry beanDefinitionRegistry) throws BeansException {
        //默认UTF-8编码，可以在构造中传入第二个参数做为编码
        FileReader fileReader = new FileReader("proxy.txt");
        List<String> classStrList = fileReader.readLines();
        Set<Class<?>> proxyClazzSet = new HashSet<>();
        for (String s : classStrList) {
            if (StringUtils.isBlank(s)) {
                continue;
            }
            try {
                Class<?> aClass = Class.forName(s);
                proxyClazzSet.add(aClass);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }
        }

        for (Class<?> targetClazz : proxyClazzSet) {
            BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(targetClazz);
            GenericBeanDefinition definition = (GenericBeanDefinition) beanDefinitionBuilder.getRawBeanDefinition();
            //设置构造方法的参数  对于Class<?>,既可以设置为Class,也可以传Class的完全类名
            //definition.getConstructorArgumentValues().addGenericArgumentValue(targetClazz);
            definition.getConstructorArgumentValues().addGenericArgumentValue(targetClazz.getName());

            //Bean的类型，指定为某个代理接口的类型
            definition.setBeanClass(HttpProxyFactoryBean.class);
            //表示 根据代理接口的类型来自动装配
            definition.setAutowireMode(AbstractBeanDefinition.AUTOWIRE_BY_TYPE);
            beanDefinitionRegistry.registerBeanDefinition(targetClazz.getName(),definition);
        }
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {

    }
}