目錄
Java常用HTTP客戶端
-
Java原生HttpURLConnection
-
Apache HttpClient
-
OkHttp
-
Spring RestTemplate
示例
public interface Client {
/**
*
* @param body
* @return
*/
Response post(Object body) throws Exception;
}
public class ApacheHttpClient implements Client {
private static final String DEFAULT_CONTENT_TYPE_VALUE = "application/json";
private static final String DEFAULT_CHARSET_NAME = "UTF-8";
private String url;
private final HttpClient client;
private JsonSerializer jsonSerializer;
/**
*
* @param url
*/
public ApacheHttpClient(String url) {
this(url, HttpClientBuilder.create().build());
}
/**
*
* @param url
* @param client
*/
public ApacheHttpClient(String url, HttpClient client) {
this(url, client, new JacksonJsonSerializer());
}
/**
*
* @param url
* @param client
* @param jsonSerializer
*/
public ApacheHttpClient(String url, HttpClient client, JsonSerializer jsonSerializer) {
if (StringUtils.isBlank(url)) {
throw new IllegalArgumentException("Url can't be null!");
}
if (Objects.isNull(client)) {
throw new IllegalArgumentException("client can't be null!");
}
if (Objects.isNull(jsonSerializer)) {
throw new IllegalArgumentException("jsonSerializer can't be null!");
}
this.url = url;
this.client = client;
this.jsonSerializer = jsonSerializer;
}
@Override
public Response post(Object body) throws Exception {
if (Objects.isNull(body)) {
return Response.NULL_BODY_RESPONSE;
}
if (body instanceof Collection && ((Collection<?>) body).size() <= 0) {
return Response.EMPTY_BODY_RESPONSE;
}
HttpPost post = new HttpPost(url);
String jsonString = jsonSerializer.serialize(body);
StringEntity entity = new StringEntity(jsonString, DEFAULT_CHARSET_NAME);
entity.setContentType(DEFAULT_CONTENT_TYPE_VALUE);
post.setEntity(entity);
HttpResponse httpResponse = client.execute(post);
HttpEntity httpEntity = httpResponse.getEntity();
String result = EntityUtils.toString(httpEntity, "UTF-8");
Response response = new Response(httpResponse.getStatusLine().getStatusCode(),
httpResponse.getStatusLine().getReasonPhrase(), result);
httpResponse.getEntity().getContent().close();
return response;
}
}
存在問題
- 面向方法
- 耦合HTTP客戶端
- 手動處理請求響應
- 無法通用，重復編碼
面向接口實現HTTP調用
HTTP請求和響應的組成
-
請求：請求行、請求頭、請求體
-
響應：響應行、響應頭、響應體
從訪問百度主頁開始
聲明接口
package com.zby.service;
public interface BaiduClient {
@RequestLine(url = "http://www.baidu.com", method = "GET")
String index();
}
聲明注解
package com.zby.annotation;
@Inherited
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface RequestLine {
String method();
String url();
}
-
如果我能通過注入BaiduClient接口的方式調用第三方，並且新增第三方時，只需要新增類似接口，與面向過程的方式相比，是否更優雅？
-
要實現注入BaiduClient接口，那么必須解析RequestLine注解，並且生成BaiduClient對象
HOW？
- 代理模式
- 模版方法模式
- 工廠模式
聲明工廠類
package com.zby.proxy;
/**
* @author zby
* @title HTTP代理工廠
* @date 2020年6月16日
* @description
*/
public interface HttpProxyFactory {
/**
* 獲取HTTP代理對象
*
* @param clazz
* @return
*/
<T> T getProxy(Class<T> clazz);
}
抽象工廠，處理注解
package com.zby.proxy;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import com.zby.annotation.RequestLine;
/**
* @author zby
* @title 抽象代理工廠
* @date 2020年6月16日
* @description
*/
public abstract class AbstractHttpProxyFactory implements HttpProxyFactory {
private Map<Class<?>, Map<Method, RequestLine>> classMethodCacheMap = new ConcurrentHashMap<>();
@Override
public <T> T getProxy(Class<T> clazz) {
if (!clazz.isInterface()) {
throw new IllegalArgumentException();
}
Map<Method, RequestLine> methodCacheMap = classMethodCacheMap.get(clazz);
if (methodCacheMap == null) {
methodCacheMap = new HashMap<>();
Method[] methods = clazz.getDeclaredMethods();
for (Method method : methods) {
RequestLine requestLine = method.getDeclaredAnnotation(RequestLine.class);
if (requestLine == null) {
throw new IllegalArgumentException(method.getName());
}
methodCacheMap.put(method, requestLine);
}
classMethodCacheMap.putIfAbsent(clazz, methodCacheMap);
}
return createProxy(clazz, methodCacheMap);
}
/**
* 創建代理對象
*
* @param clazz
* @param methodCacheMap
* @return
*/
protected abstract <T> T createProxy(Class<T> clazz, Map<Method, RequestLine> methodCacheMap);
}
基於代理和HttpURLConnection實現
package com.zby.proxy;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Map;
import com.zby.annotation.RequestLine;
/**
* @author zby
* @title HttpURLConnectionProxyFactory
* @date 2020年6月16日
* @description
*/
public class HttpURLConnectionProxyFactory extends AbstractHttpProxyFactory {
@Override
@SuppressWarnings("unchecked")
protected <T> T createProxy(Class<T> clazz, Map<Method, RequestLine> methodCacheMap) {
return (T) Proxy.newProxyInstance(clazz.getClassLoader(), new Class[] {clazz}, new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
RequestLine requestLine = methodCacheMap.get(method);
if (requestLine == null) {
throw new IllegalArgumentException();
}
URL url = new URL(requestLine.url());
URLConnection rulConnection = url.openConnection();
HttpURLConnection httpUrlConnection = (HttpURLConnection) rulConnection;
httpUrlConnection.setRequestMethod(requestLine.method());
httpUrlConnection.connect();
InputStream inputStream = httpUrlConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder stringBuilder = new StringBuilder();
String newLine = null;
while ((newLine = bufferedReader.readLine()) != null) {
stringBuilder.append(newLine);
}
return stringBuilder.toString();
}
});
}
}
拉出來溜溜
package com.zby;
import com.zby.proxy.HttpProxyFactory;
import com.zby.proxy.HttpURLConnectionProxyFactory;
import com.zby.service.BaiduClient;
/**
* @author zby
* @title HttpProxyDemo
* @date 2020年6月16日
* @description
*/
public class HttpProxyDemo {
public static void main(String[] args) {
HttpProxyFactory httpProxyFactory = new HttpURLConnectionProxyFactory();
BaiduClient baiduClient = httpProxyFactory.getProxy(BaiduClient.class);
System.out.println(baiduClient.index());
}
}
<!DOCTYPE html><!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=http://s1.bdstatic.com/r/www/cache/bdorz/baidu.min.css><title>百度一下，你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> </div> <form id=form name=f action=//www.baidu.com/s class=fm> <input type=hidden name=bdorz_come value=1> <input type=hidden name=ie value=utf-8> <input type=hidden name=f value=8> <input type=hidden name=rsv_bp value=1> <input type=hidden name=rsv_idx value=1> <input type=hidden name=tn value=baidu><span class="bg s_ipt_wr"><input id=kw name=wd class=s_ipt value maxlength=255 autocomplete=off autofocus></span><span class="bg s_btn_wr"><input type=submit id=su value=百度一下 class="bg s_btn"></span> </form> </div> </div> <div id=u1> <a href=http://news.baidu.com name=tj_trnews class=mnav>新聞</a> <a href=http://www.hao123.com name=tj_trhao123 class=mnav>hao123</a> <a href=http://map.baidu.com name=tj_trmap class=mnav>地圖</a> <a href=http://v.baidu.com name=tj_trvideo class=mnav>視頻</a> <a href=http://tieba.baidu.com name=tj_trtieba class=mnav>貼吧</a> <noscript> <a href=http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u=http%3A%2F%2Fwww.baidu.com%2f%3fbdorz_come%3d1 name=tj_login class=lb>登錄</a> </noscript> <script>document.write('<a href="http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u='+ encodeURIComponent(window.location.href+ (window.location.search === "" ? "?" : "&")+ "bdorz_come=1")+ '" name="tj_login" class="lb">登錄</a>');</script> <a href=//www.baidu.com/more/ name=tj_briicon class=bri style="display: block;">更多產品</a> </div> </div> </div> <div id=ftCon> <div id=ftConw> <p id=lh> <a href=http://home.baidu.com>關於百度</a> <a href=http://ir.baidu.com>About Baidu</a> </p> <p id=cp>©2017 Baidu <a href=http://www.baidu.com/duty/>使用百度前必讀</a> <a href=http://jianyi.baidu.com/ class=cp-feedback>意見反饋</a> 京ICP證030173號 <img src=//www.baidu.com/img/gs.gif> </p> </div> </div> </div> </body> </html>
面向接口的好處
- 新增第三方不再是增加方法，而是增加接口
- 面向接口編程而不是面向方法編程
- 無需每次自己處理請求響應
- 隨時更換具體實現HttpURLConnectionProxyFactory而不影響原有代碼
不要重復造輪子？
- NO！是不要重復造低級輪子。
- 如果你的輪子比別人好，那么還是可以嘗試一下干掉別人的輪子。
- 比如SpringMVC干掉了Strust，Mybatis干掉了Hibernate
優化
- 架構設計
- 插件式設計
- 客戶端抽象
- 編解碼抽象
- 注解支持
- 重試支持
- 第三方適配
- Spring整合
- SpringMVC注解支持
- 負載均衡支持
- 等等等等
輪子篇-Feign
-
Feign makes writing java http clients easier
-
簡單來說，就是一個基於接口的HTTP代理生成器
先睹為快
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-core</artifactId>
<version>10.2.0</version>
</dependency>
package com.zby.feign;
import feign.Feign;
import feign.Logger;
import feign.Logger.ErrorLogger;
import feign.RequestLine;
public class FeignMain {
public static void main(String[] args) {
Baidu baidu = Feign.builder()
.logger(new ErrorLogger())
.logLevel(Logger.Level.FULL)
.target(Baidu.class, "http://www.baidu.com");
System.out.println(baidu.index());
}
}
interface Baidu {
@RequestLine(value = "GET /")
String index();
}
[Baidu#index] ---> GET http://www.baidu.com/ HTTP/1.1
[Baidu#index] ---> END HTTP (0-byte body)
[Baidu#index] <--- HTTP/1.1 200 OK (168ms)
[Baidu#index] content-length: 2381
[Baidu#index] content-type: text/html
[Baidu#index] date: Tue, 16 Jun 2020 06:50:21 GMT
[Baidu#index] server: bfe
[Baidu#index]
[Baidu#index] 【省略內容。。。。。。】
[Baidu#index] <--- END HTTP (2381-byte body)
【省略內容。。。。。。】
插件式設計
- 默認使用HttpURLConnection作為HTTP客戶端，如果需要修改為HttpClient需要干啥？
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-httpclient</artifactId>
<version>10.2.0</version>
</dependency>
package com.zby.feign;
import feign.Feign;
import feign.Logger;
import feign.Logger.ErrorLogger;
import feign.RequestLine;
import feign.httpclient.ApacheHttpClient;
public class FeignMain {
public static void main(String[] args) {
Baidu baidu = Feign.builder()
.logger(new ErrorLogger())
.logLevel(Logger.Level.FULL)
.client(new ApacheHttpClient())
.target(Baidu.class, "http://www.baidu.com");
System.out.println(baidu.index());
}
}
interface Baidu {
@RequestLine(value = "GET /")
String index();
}
- So Easy
其他組件
- feign.Feign.Builder
private final List<RequestInterceptor> requestInterceptors =
new ArrayList<RequestInterceptor>();
private Logger.Level logLevel = Logger.Level.NONE;
private Contract contract = new Contract.Default();
private Client client = new Client.Default(null, null);
private Retryer retryer = new Retryer.Default();
private Logger logger = new NoOpLogger();
private Encoder encoder = new Encoder.Default();
private Decoder decoder = new Decoder.Default();
private QueryMapEncoder queryMapEncoder = new QueryMapEncoder.Default();
private ErrorDecoder errorDecoder = new ErrorDecoder.Default();
private Options options = new Options();
private InvocationHandlerFactory invocationHandlerFactory =
new InvocationHandlerFactory.Default();
private boolean decode404;
private boolean closeAfterDecode = true;
private ExceptionPropagationPolicy propagationPolicy = NONE;
注解解析：契約
- feign.Contract支持的注解：Body、HeaderMap、Headers、Param、QueryMap、RequestLine
- 實現feign.Contract定制屬於你自己的契約
- 集成SpringMvc注解：org.springframework.cloud.openfeign.support.SpringMvcContract
- 官方只有Spring4的：https://github.com/OpenFeign/feign/blob/feign-11/spring4/src/main/java/feign/spring/SpringContract.java
- Spring-cloud-openfeign-core:org.springframework.cloud.openfeign.support.SpringMvcContract
實戰篇-對接GIO
一、定義接口
/**
* 獲取事件分析數據，文檔地址：
* https://docs.growingio.com/docs/developer-manual/api-reference/statistics-api/definition/getevent
*
* @author zby
* @Date 2020年4月20日
*
*/
public interface EventAnalysisClient {
/**
* 獲取事件分析數據
*
* @param projectUid 項目ID
* @param chartId 圖表ID
* @param eventAnalysisRequest 參數
* @return
*/
@RequestLine("GET /v2/projects/{project_uid}/charts/{chart_id}.json")
EventAnalysisResponse getEvent(@Param("project_uid") String projectUid, @Param("chart_id") String chartId,
@QueryMap EventAnalysisRequest eventAnalysisRequest);
}
二、Feign抽象配置
/**
* GIOFeign抽象配置
*
* @author zby
* @Date 2020年4月21日
*
*/
public class AbstractGIOFeignConfiguration {
/**
* GIO官網地址
*/
@Value("${gio.url}")
private String gioUrl;
/**
* 認證信息
*/
@Value("${gio.authorization}")
private String authorization;
/**
* 創建Feign代理對象
*
* @param clazz
* @return
*/
protected <T> T newInstance(Class<T> clazz) {
return feign().newInstance(new Target.HardCodedTarget<T>(clazz, gioUrl));
}
/**
* 公用的Feign對象
*
* @return
*/
@SuppressWarnings("deprecation")
private Feign feign() {
return Feign.builder()
.logger(new Slf4jLogger())
.logLevel(Level.BASIC)
.encoder(new JacksonEncoder())
.decoder(new JacksonDecoder())
.requestInterceptor(new AuthorizationInterceptor())
// 處理null
.queryMapEncoder(new QueryMapEncoder.Default() {
@Override
public Map<String, Object> encode(Object object) throws EncodeException {
if (object == null) {
return new HashMap<String, Object>();
}
return super.encode(object);
}
})
.build();
}
/**
* GIO認證信息攔截器
*
* @author zby
* @Date 2020年4月20日
*
*/
class AuthorizationInterceptor implements RequestInterceptor {
@Override
public void apply(RequestTemplate template) {
template.header("Authorization", authorization);
}
}
}
三、注入IOC容器
/**
* GIO的feig客戶端配置類
*
* @author zby
* @Date 2020年4月21日
*
*/
@Configuration
public class GIOFeignConfiguration extends AbstractGIOFeignConfiguration {
/**
* 創建事件分析Feign客戶端，代優化：定義注解FeignClient直接掃描創建實例放到spring容器
*
* @return
*/
@Bean
public EventAnalysisClient eventAnalysisClient() {
return newInstance(EventAnalysisClient.class);
}
}
四、使用
/**
* 事件分析GIO客戶端實現
*
* @author zby
* @Date 2020年4月21日
*
*/
@Service
public class EventAnalysisGIOClientImpl implements EventAnalysisGIOClient {
private static final Logger LOGGER = LoggerFactory.getLogger(EventAnalysisGIOClientImpl.class);
@Autowired
private EventAnalysisClient eventAnalysisClient;
@Override
public List<NewsListEventAnalysisDto> getNewsListData(EventAnalysisRequest eventAnalysisRequest) {
List<NewsListEventAnalysisDto> list;
try {
LOGGER.info("獲取GIO新聞列表數據參數：eventAnalysisRequest={}", eventAnalysisRequest);
EventAnalysisResponse eventAnalysisResponse = eventAnalysisClient.getEvent(GIOConstant.PROJECT_UID,
EventAnalysisConstant.CHART_ID_NEWS_LIST, eventAnalysisRequest);
LOGGER.info("獲取GIO新聞列表數據結果：{}", eventAnalysisResponse);
list = EventAnalysisUtil.parse(eventAnalysisResponse,
new AbstractGIOFieldObjectFactory<NewsListEventAnalysisDto>() {});
} catch (Exception e) {
LOGGER.error(String.format("獲取GIO新聞列表數據出錯,請求參數：%s", eventAnalysisRequest), e);
return null;
}
return list;
}
}
贈送篇-結果封裝
- GIO數據結果通用格式
- 基於注解、反射、工廠模式、反省、BeanWrapper等封裝通用數據格式為業務對象
/**
* 事件分析響應實體
*
* @author zby
* @Date 2020年4月20日
*
*/
@Data
public class EventAnalysisResponse {
/**
* Chart Uid
*/
private String id;
/**
* Chart Name
*/
private String name;
/**
* 同參數
*/
private Long startTime;
/**
* 同參數
*/
private Long endTime;
/**
* 同參數
*/
private Long interval;
/**
* 表格頭元數據
*/
private Meta[] meta;
/**
* 表格數據
*/
private String[][] data;
/**
* 元數據，標題列
*
* @author zby
* @Date 2020年4月21日
*
*/
@Data
@NoArgsConstructor
@AllArgsConstructor
public static class Meta {
/**
* 名稱
*/
private String name;
/**
* 方面
*/
private boolean dimension;
/**
* 統計數據
*/
private boolean metric;
}
}