HttpClient 4.5.x 工具类设计与实现

最近,业务需要在java服务端发起http请求,需要实现"GET","POST","PUT"等基本方法。于是想以 "HttpClient" 为基础,封装基本实现方法。在github上面看到一个项目cn-umbrella/httpclientDemo,里面实现简单的 "GET","POST"。一方面,demo中实现的逻辑不能满足业务需要,同时实现过程中,存在使用过期的类,代码封装不足等问题。也是我就重新封装了httpclient-util,抱着大家相互学习的心态,将代码上传到github上面,,错误的地方欢迎大家指正。回归正题,下面讲讲工具类实现的基本思路。1.主要依赖<dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.2</version> </dependency> <!--httpmime主要用于构建multi-part/form-data 请求--> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpmime</artifactId> <version>4.5.2</version> </dependency>2.HttpClientUtil 主要方法
/**
 * Do http request
 * @param request request object
 * @return response object
 */
public static Response doRequest(Request request)
其中,Request 封装了请求参数,Response 封装了返回内容。3.Request 说明支持方法:"GET","OPTIONS","HEAD","POST","PUT","PATCH"。支持请求体: "application/x-www-form-urlencoded","json字符串","multipart/form-data"。Request的继承关系 Request (没有请求body的请求,支持方法:"GET", "OPTIONS", "HEAD") |---BaseEntityRequest (抽象类,定义有请求body的请求, 支持方法:"POST", "PUT", "PATCH") |--- UrlEncodedFormRequest (application/x-www-form-urlencoded) |--- JsonRequest (请求body为json字符串) |--- MultiPartFormRequest (multipart/form-data)同时,Request 支持使用 ssl/tls,使用request.setUseSSL(true);设置即可。HttpEntity就是对应请求body相关实体对象。3.BaseEntityRequest 介绍任何实现具有请求body的请求,需要实现 BaseEntityRequest 以下方法/** * Get HttpEntity about request body * @return HttpEntity */ public abstract HttpEntity getEntity();3.1 UrlEncodedFormRequest 核心代码这个实现比较简单,"K-V" 的形式,返回 UrlEncodedFormEntity,注意参数编码。@Override public HttpEntity getEntity() { List<NameValuePair> pairList = new ArrayList<>(params.size()); for (Map.Entry<String, Object> entry : params.entrySet()) { NameValuePair pair = new BasicNameValuePair(entry.getKey(), entry .getValue().toString()); pairList.add(pair); } return new UrlEncodedFormEntity(pairList, Charset.forName(getRequestCharset())); //参数编码 }3.2 JsonRequest 核心代码请求body就是一个 "json字符串",返回一个StringEntity 实体即可。@Override public HttpEntity getEntity() { StringEntity stringEntity = new StringEntity(jsonObject.toString(), getRequestCharset()); //解决中文乱码问题,需要注意编码,如使用"utf-8" stringEntity.setContentEncoding(getResponseDefaultCharset()); stringEntity.setContentType(JSON_CONTENT_TYPE); return stringEntity; }3.3 MultiPartFormRequest 核心代码httpclient 类库中不直接支持构造 "multi-part/form-data" ,需要引入 httpmime,并使用 MultipartEntityBuilder 构造请求body。如果是文件类型的参数对象,使用 FileBody 构建 part,否则,使用 StringBody,注意编码。@Override public HttpEntity getEntity() { try { Charset charset = CharsetUtils.get(getRequestCharset()); //使用浏览器兼容模式,并且设置编码,防止文件名乱码问题 MultipartEntityBuilder builder = MultipartEntityBuilder.create() .setMode(HttpMultipartMode.BROWSER_COMPATIBLE) .setCharset(charset); //编码 parts.forEach((key, value) -> { if (null != value && value instanceof File) { //for file FileBody fileBody = new FileBody((File) value); builder.addPart(key, fileBody); } else { StringBody stringBody = new StringBody(null == value ? "" : value.toString() , ContentType.create(ContentType.TEXT_PLAIN.getMimeType(), charset)); //编码 builder.addPart(key, stringBody); } }); return builder.build(); } catch (UnsupportedEncodingException e) { throw new RuntimeException("Charset '" + getRequestCharset() + "' is unsupported!"); } }4.注意地方使用 https 过程中,如果出现下述异常:javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at sun.security.ssl.Alerts.getSSLException(Alerts.java:192) at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1949) at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:302) at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:296) ... Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:387) at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:292) at sun.security.validator.Validator.validate(Validator.java:260) at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324) at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229) 可以参考我的上篇博文,当然在包 com.xiaobenma020.http.cert 下面可以找到类 InstallCert关键步骤% java InstallCert _web_site_hostname_ 显示相关的证书信息 此时输入'q' 则为'退出', '1' 则将添加CA证书。 将新生成的 "jssecacerts" 移到"$JAVA_HOME/jre/lib/security"5.使用demo@Test public void doResponse() throws Exception { UrlEncodedFormRequest request = new UrlEncodedFormRequest("https://xxx.com/login", RequestMethod.POST); //url form param request.addParam("loginId", "loginId"); request.addParam("password", "password"); //query string param request.addUrlParam("version", "v1"); //ssl request.setUseSSL(true); Response response = HttpClientUtil.doRequest(request); System.out.println(response.getResponseText()); //response text System.out.println(response.getCode()); //response code System.out.println(response.getHeader("Set-Cookie")); }

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