让http请求的调用更优雅

概述

当我们提到java调用http请求时，我们想到的是HttpClient或是内置的HttpUrlConnention。然后会写下如下一串的代码访问http接口：

        HttpClient client = new HttpClient();
        client.getHostConfiguration().setProxy("127.0.0.1", 8888);
        client.getHostConfiguration().setHost("bl.ocks.org", 80, "http");
        GetMethod getMethod = new GetMethod("/mbostock/raw/4090846/us-congress-113.json");
        client.executeMethod(getMethod);
        //打印服务器返回的状态
        System.out.println(getMethod.getStatusLine().getStatusCode());
        if(getMethod.getStatusLine().getStatusCode() == 200){
            //打印结果页面
            String response = new String(getMethod.getResponseBodyAsString().getBytes("8859_1"));

            //打印返回的信息
            System.out.println(response);
        }
        getMethod.releaseConnection();

可是我们是不是有一种更优雅的方式呢？类似于MyBatis，通过一定的配置，然后在需要请求http接口的时候只需要调用一个接口函数便可以完成上述代码的工作。

这就是HttpFetch的初衷，让http请求的调用更优雅。

下载

git clone https://github.com/youzan/httpfetch.git

QuickStart

https://github.com/youzan/httpfetch/wiki/QuickStart

对象

ParameterResolver：api参数解析类，自带的可以对数组、bean、简单类型等参数进行解析并封装成Get、Post、Form等类型请求的参数。也可以通过Url注解灵活定义api接口的请求地址。
Convertor：返回数据封装类，自带的仅支持简单类型和JSON类型的数据进行封装。通过扩展可以实现更多的转换方式。
Chain：责任链模式，一层层对请求进行加工和处理。里面比较重要的是ParameterResolverChain、GenerateResponseChain和ExecuteRequestChain。ParameterResolverChain负责对参数进行处理，GenerateResponseChain负责对返回结果进行处理，ExecuteRequestChain负责最后的请求发送。
ResourceReader: 配置信息读取类，负责对各组件单元的读取并最终传给HttpApiConfiguration类。
HttpApiConfiguration：负责对ResourceReader读取后的配置信息进行封装，然后将配置信息传给HttpApiService类。
HttpApiService：负责最后的代理类生成和缓存；

框架

初始化过程

初始化过程可以选择spring和xml两种。spring的方式直接将生成的代理类注册到BeanDefinitionRegistry（可见HttpApiClassPathBeanDefinitionScanner源码），xml方式可以在没有spring组件的情况下独立运行（见单测MbostockApiUseXmlTest）。两种方式都可以完成Chain、ParamterResolver和Convertor注册。
请求处理流程请求者发起请求时，会通过配置的各个Chain单元，一步一步的处理和封装参数并发送最终的Http请求，最后将返回的值进行封装。

使用

Maven

<dependency>
    <groupId>com.github.youzan</groupId>
    <artifactId>http-fetch</artifactId>
    <version>1.1.6</version>
</dependency>

非spring调用

1.创建http-api.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<setting>

    <!-- 请求处理链 -->
    <chains>
    </chains>

    <!-- 参数处理类 -->
    <argumentResolvers>
    </argumentResolvers>

    <!-- 结果处理类 -->
    <resultConvertors>
    </resultConvertors>

    <!-- api和url映射关系 -->
    <aliases>
        <alias key="mbostockApi.getUsCongress" value="https://bl.ocks.org/mbostock/raw/4090846/us-congress-113.json" />
    </aliases>

</setting>

2.编写MbostockApi接口类：

package com.github.nezha.httpfetch.mbostock.api;

import com.github.nezha.httpfetch.HttpApi;
import com.github.nezha.httpfetch.Header;
import com.github.nezha.httpfetch.mbostock.vo.UsCongressResponseVo;

/**
 * Created by daiqiang on 17/3/14.
 */
public interface MbostockApi {

    @HttpApi(timeout = 1000, headers = {@Header(key="user-agent", value = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36")})
    UsCongressResponseVo getUsCongress();

}

3.编写测试类：

        SourceReader xmlReader = new XmlReader(Arrays.asList("httpapi.xml"));

        HttpApiConfiguration configuration = new HttpApiConfiguration();
        configuration.setSourceReaders(Arrays.asList(xmlReader));
        configuration.init();

        HttpApiService service = new HttpApiService(configuration);
        service.init();

        MbostockApi mbostockApi = service.getOrCreateService(MbostockApi.class);

        UsCongressResponseVo responseVo = mbostockApi.getUsCongress();
        System.out.println("type=="+responseVo.getType());
        System.out.println("arcs->size=="+responseVo.getArcs().size());
        System.out.println("objects->districts->bbox->size=="+responseVo.getObjects().getDistricts().getBbox().size());
        System.out.println("objects->districts->type=="+responseVo.getObjects().getDistricts().getType());
        System.out.println("objects->districts->geometries->size=="+responseVo.getObjects().getDistricts().getGeometries().size());
        System.out.println("transform->scale=="+responseVo.getTransform().getScale());
        System.out.println("transform->translate=="+responseVo.getTransform().getTranslate());

以上就是非spring方式的调用

spring方式的调用

1.创建application-httpapi.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	   xsi:schemaLocation="
		    http://www.springframework.org/schema/beans
		    http://www.springframework.org/schema/beans/spring-beans.xsd
	    ">

	<bean id="springReader" class="com.github.nezha.httpfetch.spring.SpringReader" >
	    <!-- 请求处理链 -->
		<property name="chains" >
			<list>
				<bean class="com.github.nezha.httpfetch.bookworm.chains.BookWormTokenChain" />
			</list>
		</property>
		<!-- 参数处理类 -->
		<property name="parameterResolvers">
			<list>
			</list>
		</property>
		<!-- 结果处理类 -->
		<property name="convertors">
			<list>
			</list>
		</property>
		<!-- api和url映射关系 -->
		<property name="urlAlias">
			<map>
				<entry key="mbostockApi.getUsCongress" value="${mock.host}/mbostock/raw/4090846/us-congress-113.json" />
			</map>
		</property>
	</bean>

	<bean id="httpApiConfiguration" class="com.github.nezha.httpfetch.HttpApiConfiguration" init-method="init">
		<property name="sourceReaders">
			<list>
				<ref bean="springReader" />
			</list>
		</property>
	</bean>

	<bean id="httpApiService" class="com.github.nezha.httpfetch.HttpApiService" init-method="init">
		<constructor-arg index="0" ref="httpApiConfiguration" />
	</bean>

    <!-- http api代理注册 -->
	<bean class="com.github.nezha.httpfetch.spring.HttpApiScannerConfigurer">
		<property name="basePackage" value="com.github.nezha.httpfetch.bookworm.api,com.github.nezha.httpfetch.mbostock.api,com.github.nezha.httpfetch.youzan.api" />
	</bean>

</beans>

2.编写MbostockApi接口类：

package com.github.nezha.httpfetch.mbostock.api;

import com.github.nezha.httpfetch.HttpApi;
import com.github.nezha.httpfetch.Header;
import com.github.nezha.httpfetch.mbostock.vo.UsCongressResponseVo;

/**
 * Created by daiqiang on 17/3/14.
 */
public interface MbostockApi {

    @HttpApi(timeout = 1000, headers = {@Header(key="user-agent", value = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36")})
    UsCongressResponseVo getUsCongress();

}

3.编写测试类：

public class MbostockApiTest extends BaseTest {

    @Autowired
    private MbostockApi mbostockApi;

    @Test
    public void test(){
        UsCongressResponseVo responseVo = mbostockApi.getUsCongress();
        System.out.println("type=="+responseVo.getType());
        System.out.println("arcs->size=="+responseVo.getArcs().size());
        System.out.println("objects->districts->bbox->size=="+responseVo.getObjects().getDistricts().getBbox().size());
        System.out.println("objects->districts->type=="+responseVo.getObjects().getDistricts().getType());
        System.out.println("objects->districts->geometries->size=="+responseVo.getObjects().getDistricts().getGeometries().size());
        System.out.println("transform->scale=="+responseVo.getTransform().getScale());
        System.out.println("transform->translate=="+responseVo.getTransform().getTranslate());
    }

}

URL映射

url的映射使用了三种方式：

1.使用xml进行配置：

    <aliases>
        <alias key="mbostockApi.getUsCongress" value="https://bl.ocks.org/mbostock/raw/4090846/us-congress-113.json" />
    </aliases>

2.使用注解方式：

package com.github.nezha.httpfetch.bookworm.api;

import com.github.nezha.httpfetch.Header;
import com.github.nezha.httpfetch.HttpApi;
import com.github.nezha.httpfetch.resolver.RequestBody;

import java.util.Map;

/**
 * Created by daiqiang on 17/6/16.
 */
public interface AlarmJobApi {

    @HttpApi(method = "POST", headers = @Header(url = "http://alert.s.qima-inc.com/api/v1/alert", key = "Content-type", value = "application/json"), timeout = 2000)
    String alert(@RequestBody Map<String, Object> param);

}

3.使用参数方式传入：

    @HttpApi(timeout = 1000, headers = {@Header(key="user-agent", value = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36")})
    UsCongressResponseVo getUsCongress(@URL String url);

测试类：

    public void test_url_param(){
        String url = "https://bl.ocks.org/mbostock/raw/4090846/us-congress-113.json";
        UsCongressResponseVo responseVo = mbostockApi.getUsCongress(url);
        System.out.println("type=="+responseVo.getType());
        System.out.println("arcs->size=="+responseVo.getArcs().size());
        System.out.println("objects->districts->bbox->size=="+responseVo.getObjects().getDistricts().getBbox().size());
        System.out.println("objects->districts->type=="+responseVo.getObjects().getDistricts().getType());
        System.out.println("objects->districts->geometries->size=="+responseVo.getObjects().getDistricts().getGeometries().size());
        System.out.println("transform->scale=="+responseVo.getTransform().getScale());
        System.out.println("transform->translate=="+responseVo.getTransform().getTranslate());
    }

参数封装

1.Get请求参数：使用QueryParam注解标记，并填写参数的名称

    @HttpApi(timeout = 2000, url = "http://bookworm365.com/uploadImage")
    @BookWormApi
    UploadFileResponseVo uploadFile(@QueryParam("name") String name,
                                    @QueryParam("n_value") String nValue);

2.Post请求参数：使用PostParam注解标记，并填写参数的名称

Map audit(@PostParam("advertisementId") Integer advertisementId);

3.Form请求参数：使用FormParam注解标记，并填写参数的名称

    @HttpApi(timeout = 2000, url = "http://bookworm365.com/uploadImage")
    @BookWormApi
    UploadFileResponseVo uploadFile(@FormParam("file") File file,
                                    @QueryParam("name") String name,
                                    @QueryParam("n_value") String nValue);

4.BeanParam注解使用：当我们传递一个bean做为参数，但是希望对这个bean进行解析然后作为http请求参数时，我们可以使用BeanParam注解。

    @HttpApi(timeout = 2000, url = "http://bookworm365.com/uploadImage")
    @BookWormApi
    UploadFileResponseVo uploadFile(@BeanParam @QueryParam UploadFileRequestVo requestVo);

package com.github.nezha.httpfetch.bookworm.vo;

import com.alibaba.fastjson.annotation.JSONField;
import java.io.File;

public class UploadFileRequestVo {
    @JSONField(name = "file")
    private File file;
    private String name;
    @JSONField(name="n_value")
    private String nValue;
    public File getFile() {return file;}
    public void setFile(File file) {this.file = file;}
    public String getName() {return name;}
    public void setName(String name) {this.name = name;}
    public String getnValue() {return nValue;}
    public void setnValue(String nValue) {this.nValue = nValue;}
}

http的请求最终为：http://bookworm365.com/uploadImage?file=XXX&name=XXX&n_value=XXX

5.RequestBody注解使用：当你需要传递消息体给服务器是，可以通过该注解。例如我们想要传递一个application\json的请求：

    @HttpApi(method = "POST",timeout = 2000,headers = {@Header(key = "Content-type", value = "application/json;charset=UTF-8")})
    @WechatApi
    WechatBaseResponseVo<AddCustomAudiencesResponseVo> add(@RequestBody AddCustomAudiencesRequestVo requestVo);

结果封装

结果封装默认支持简单类型和JSON两种： 1.简单类型，如果返回值是String、int、long等，api的返回对象可以直接指定对应类：

    @HttpApi(timeout = 2000, url = "http://bookworm365.com/checkHeader")
    @BookWormApi
    String checkHeader();

2.JSON，如果返回值是一个json字符串，可以直接编写对应的bean作为返回类，内部使用fastjson进行反序列化：

    @HttpApi(timeout = 1000, headers = {@Header(key="user-agent", value = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36")})
    UsCongressResponseVo getUsCongress();

package com.github.nezha.httpfetch.mbostock.vo;

import com.alibaba.fastjson.annotation.JSONField;
import java.util.List;

public class UsCongressResponseVo {
    @JSONField(name="type")
    private String type;
    @JSONField(name="objects")
    private ObjectsVo objects;
    @JSONField(name="arcs")
    private List<List<List<Integer>>> arcs;
    @JSONField(name="transform")
    private TransformVo transform;
    public String getType() {return type;}
    public void setType(String type) {this.type = type;}
    public ObjectsVo getObjects() {return objects;}
    public void setObjects(ObjectsVo objects) {this.objects = objects;}
    public List<List<List<Integer>>> getArcs() {return arcs;}
    public void setArcs(List<List<List<Integer>>> arcs) {this.arcs = arcs;}
    public TransformVo getTransform() {return transform;}
    public void setTransform(TransformVo transform) {this.transform = transform;}
}

package com.github.nezha.httpfetch.mbostock.vo;

import com.alibaba.fastjson.annotation.JSONField;
import com.github.nezha.httpfetch.BaseTest;

public class ObjectsVo {
    @JSONField(name="districts")
    private DistrictsVo districts;
    public DistrictsVo getDistricts() {return districts;}
    public void setDistricts(DistrictsVo districts) {this.districts = districts;}
}

另外返回的类还支持泛型。

@HttpApi(timeout = 1000, headers = {@Header(key="user-agent", value = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36")})
    UsCongressResponseVo<TransformVo> getUsCongress();

重试策略

需要升级到1.2.0之后才可以使用。
HttpApi注解中增加了retry和retryPolicy两个变量：
retry：重试次数；
retryPolicy：重试策略，默认为ConnectFailureRetryPolicy，超时和连接异常会进行重试；

自定义重试策略

类图：

所有的重试策略需要继承RetryPolicy接口，并实现needRetry函数。

/** 
 * 重试校验接口 
 */  
public interface RetryPolicy {  
  
    /** 
     * 
     * @param result http请求结果 
     * @param retryTimes 重试次数 
     * @param remainRetryTimes  剩余重试次数 
     * @return 
     */  
    boolean needRetry(HttpResult result, int retryTimes, int remainRetryTimes);  
  
}

ConnectFailureRetryPolicy：

public class ConnectFailureRetryPolicy implements RetryPolicy {  
  
    private static final Logger LOGGER = LoggerFactory.getLogger(ConnectFailureRetryPolicy.class);  
  
    /** 
     * 如果是网络异常则重试 
     * @param result http请求结果 
     * @param retryTimes 重试次数 
     * @param remainRetryTimes  剩余重试次数 
     * @return 
     */  
    @Override  
    public boolean needRetry(HttpResult result, int retryTimes, int remainRetryTimes) {  
        Exception e = result.getException();  
        if(e instanceof SocketTimeoutException || e instanceof ConnectException){  
            LOGGER.info("超时重试: {}, 重试次数: {} 剩余次数: {}", e, retryTimes, remainRetryTimes);  
            return true;  
        }  
        return false;  
    }  
  
}

实现完自己的重试策略后，只需要在HttpApi注解中设置retryPolicy的值就可以了。

更多示例可以在项目的test目录中查看

开源协议

本项目基于 MIT协议，请自由地享受和参与开源。

贡献

如果你有好的意见或建议，欢迎给我们提 [issue] 或 [PR]，为优化 [http-fetch] 贡献力量