让http请求的调用更优雅
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。
git clone https://github.com/youzan/httpfetch.githttps://github.com/youzan/httpfetch/wiki/QuickStart
- 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；
-
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。
<dependency>
<groupId>com.github.youzan</groupId>
<artifactId>http-fetch</artifactId>
<version>1.1.6</version>
</dependency>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
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());
}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();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；
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
本项目基于 MIT协议，请自由地享受和参与开源。
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
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