浅谈java调用Restful API接口的方式

2023-09-19 04:19:05 68

摘要：最近有一个需求，为客户提供一些RestfulAPI接口，QA使用postman进行测试，但是postman的测试接口与java调用的相似但并不相同，于是想自己写一个程序去测试RestfulAPI接口，由于使用的是HTTPS，所以还要考虑到对于HTTPS的处理。由于我也是首次使用Java调用restful接口，所以还要研究一番，自然也是查阅了一些资料。

分析：这个问题与模块之间的调用不同，比如我有两个模块frontend和backend，frontend提供前台展示，backend提供数据支持。之前使用过Hession去把backend提供的服务注册成远程服务，在frontend端可以通过这种远程服务直接调到backend的接口。但这对于一个公司自己的一个项目耦合性比较高的情况下使用，没有问题。但是如果给客户注册这种远程服务，似乎不太好，耦合性太高。所以就考虑用一下方式进行处理。

基本介绍

Restful接口的调用，前端一般使用ajax调用，后端可以使用的方法比较多，

本次介绍三种：

1.HttpURLConnection实现

2.HttpClient实现

3.Spring的RestTemplate

一、HttpClient

HttpClient大家也许比较熟悉但又比较陌生，熟悉是知道他可以远程调用比如请求一个URL，然后在response里获取到返回状态和返回信息，但是今天讲的稍微复杂一点，因为今天的主题是HTTPS，这个牵涉到证书或用户认证的问题。

确定使用HttpClient之后，查询相关资料，发现HttpClient的新版本与老版本不同，随然兼容老版本，但已经不提倡老版本是使用方式，很多都已经标记为过时的方法或类。今天就分别使用老版本4.2和最新版本4.5.3来写代码。

老版本4.2

需要认证

在准备证书阶段选择的是使用证书认证

packagecom.darren.test.https.v42;
importjava.io.File;
importjava.io.FileInputStream;
importjava.security.KeyStore;
importorg.apache.http.conn.ssl.SSLSocketFactory;
publicclassHTTPSCertifiedClientextendsHTTPSClient{
	publicHTTPSCertifiedClient(){
	}
	@Override
	publicvoidprepareCertificate()throwsException{
		//获得密匙库
		KeyStoretrustStore=KeyStore.getInstance(KeyStore.getDefaultType());
		FileInputStreaminstream=newFileInputStream(
		newFile("C:/Users/zhda6001/Downloads/software/xxx.keystore"));
		//FileInputStreaminstream=newFileInputStream(newFile("C:/Users/zhda6001/Downloads/xxx.keystore"));
		//密匙库的密码
		trustStore.load(instream,"password".toCharArray());
		//注册密匙库
		this.socketFactory=newSSLSocketFactory(trustStore);
		//不校验域名
		socketFactory.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
	}
}

跳过认证

在准备证书阶段选择的是跳过认证

packagecom.darren.test.https.v42;
importjava.security.cert.CertificateException;
importjava.security.cert.X509Certificate;
importjavax.net.ssl.SSLContext;
importjavax.net.ssl.TrustManager;
importjavax.net.ssl.X509TrustManager;
importorg.apache.http.conn.ssl.SSLSocketFactory;
publicclassHTTPSTrustClientextendsHTTPSClient{
	publicHTTPSTrustClient(){
	}
	@Override
	publicvoidprepareCertificate()throwsException{
		//跳过证书验证
		SSLContextctx=SSLContext.getInstance("TLS");
		X509TrustManagertm=newX509TrustManager(){
			@Override
			publicvoidcheckClientTrusted(X509Certificate[]chain,StringauthType)throwsCertificateException{
			}
			@Override
			publicvoidcheckServerTrusted(X509Certificate[]chain,StringauthType)throwsCertificateException{
			}
			@Override
			publicX509Certificate[]getAcceptedIssuers(){
				returnnull;
			}
		}
		;
		//设置成已信任的证书
		ctx.init(null,newTrustManager[]{
			tm
		}
		,null);
		//穿件SSLsocket工厂，并且设置不检查host名称
		this.socketFactory=newSSLSocketFactory(ctx,SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
	}
}

总结

现在发现这两个类都继承了同一个类HTTPSClient，并且HTTPSClient继承了DefaultHttpClient类，可以发现，这里使用了模板方法模式。

packagecom.darren.test.https.v42;
importorg.apache.http.conn.ClientConnectionManager;
importorg.apache.http.conn.scheme.Scheme;
importorg.apache.http.conn.scheme.SchemeRegistry;
importorg.apache.http.conn.ssl.SSLSocketFactory;
importorg.apache.http.impl.client.DefaultHttpClient;
publicabstractclassHTTPSClientextendsDefaultHttpClient{
	protectedSSLSocketFactorysocketFactory;
	/**
*初始化HTTPSClient
*
*@return返回当前实例
*@throwsException
*/
	publicHTTPSClientinit()throwsException{
		this.prepareCertificate();
		this.regist();
		returnthis;
	}
	/**
*准备证书验证
*
*@throwsException
*/
	publicabstractvoidprepareCertificate()throwsException;
	/**
*注册协议和端口,此方法也可以被子类重写
*/
	protectedvoidregist(){
		ClientConnectionManagerccm=this.getConnectionManager();
		SchemeRegistrysr=ccm.getSchemeRegistry();
		sr.register(newScheme("https",443,socketFactory));
	}
}

下边是工具类

packagecom.darren.test.https.v42;
importjava.util.ArrayList;
importjava.util.List;
importjava.util.Map;
importjava.util.Set;
importorg.apache.http.HttpEntity;
importorg.apache.http.HttpResponse;
importorg.apache.http.NameValuePair;
importorg.apache.http.client.entity.UrlEncodedFormEntity;
importorg.apache.http.client.methods.HttpGet;
importorg.apache.http.client.methods.HttpPost;
importorg.apache.http.client.methods.HttpRequestBase;
importorg.apache.http.message.BasicNameValuePair;
importorg.apache.http.util.EntityUtils;
publicclassHTTPSClientUtil{
	privatestaticfinalStringDEFAULT_CHARSET="UTF-8";
	publicstaticStringdoPost(HTTPSClienthttpsClient,Stringurl,MapparamHeader,
	MapparamBody)throwsException{
		returndoPost(httpsClient,url,paramHeader,paramBody,DEFAULT_CHARSET);
	}
	publicstaticStringdoPost(HTTPSClienthttpsClient,Stringurl,MapparamHeader,
	MapparamBody,Stringcharset)throwsException{
		Stringresult=null;
		HttpPosthttpPost=newHttpPost(url);
		setHeader(httpPost,paramHeader);
		setBody(httpPost,paramBody,charset);
		HttpResponseresponse=httpsClient.execute(httpPost);
		if(response!=null){
			HttpEntityresEntity=response.getEntity();
			if(resEntity!=null){
				result=EntityUtils.toString(resEntity,charset);
			}
		}
		returnresult;
	}
	publicstaticStringdoGet(HTTPSClienthttpsClient,Stringurl,MapparamHeader,
	MapparamBody)throwsException{
		returndoGet(httpsClient,url,paramHeader,paramBody,DEFAULT_CHARSET);
	}
	publicstaticStringdoGet(HTTPSClienthttpsClient,Stringurl,MapparamHeader,
	MapparamBody,Stringcharset)throwsException{
		Stringresult=null;
		HttpGethttpGet=newHttpGet(url);
		setHeader(httpGet,paramHeader);
		HttpResponseresponse=httpsClient.execute(httpGet);
		if(response!=null){
			HttpEntityresEntity=response.getEntity();
			if(resEntity!=null){
				result=EntityUtils.toString(resEntity,charset);
			}
		}
		returnresult;
	}
	privatestaticvoidsetHeader(HttpRequestBaserequest,MapparamHeader){
		//设置Header
		if(paramHeader!=null){
			SetkeySet=paramHeader.keySet();
			for(Stringkey:keySet){
				request.addHeader(key,paramHeader.get(key));
			}
		}
	}
	privatestaticvoidsetBody(HttpPosthttpPost,MapparamBody,Stringcharset)throwsException{
		//设置参数
		if(paramBody!=null){
			Listlist=newArrayList();
			SetkeySet=paramBody.keySet();
			for(Stringkey:keySet){
				list.add(newBasicNameValuePair(key,paramBody.get(key)));
			}
			if(list.size()>0){
				UrlEncodedFormEntityentity=newUrlEncodedFormEntity(list,charset);
				httpPost.setEntity(entity);
			}
		}
	}
}

然后是测试类：

packagecom.darren.test.https.v42;
importjava.util.HashMap;
importjava.util.Map;
publicclassHTTPSClientTest{
	publicstaticvoidmain(String[]args)throwsException{
		HTTPSClienthttpsClient=null;
		httpsClient=newHTTPSTrustClient().init();
		//httpsClient=newHTTPSCertifiedClient().init();
		Stringurl="https://1.2.6.2:8011/xxx/api/getToken";
		//Stringurl="https://1.2.6.2:8011/xxx/api/getHealth";
		MapparamHeader=newHashMap<>();
		//paramHeader.put("Content-Type","application/json");
		paramHeader.put("Accept","application/xml");
		MapparamBody=newHashMap<>();
		paramBody.put("client_id","ankur.tandon.ap@xxx.com");
		paramBody.put("client_secret","P@ssword_1");
		Stringresult=HTTPSClientUtil.doPost(httpsClient,url,paramHeader,paramBody);
		//Stringresult=HTTPSClientUtil.doGet(httpsClient,url,null,null);
		System.out.println(result);
	}
}

返回信息：


jkf8RL0sw+Skkflj8RbKI5hP1bEQK8PrCuTZPpBINqMYKRMxY1kWCjmCfT191Zpp88VV1aGHW8oYNWjEYS0axpLuGAX89ejCoWNbikCc1UvfyesXHLktcJqyUFiVjevhrEQxJPHncLQYWP+Xse5oD9X8vKFKk7InNTMRzQK7YBTZ/e3U7gswM/5cvAHFl6o9rEq9cWPXavZNohyvnXsohSzDo+BXAtXxa1xpEDLy/8h/UaP4n4dlZDJJ3B8t1Xh+CRRIoMOPxf7c5wKhHtOkEOeXW+xoPQKKSx5CKWwJpPuGIIFWF/PaqWg+JUOsVT7QGdPv8PMWJ9DwEwjTdxguDg==

新版本4.5.3

需要认证

packagecom.darren.test.https.v45;
importjava.io.File;
importjava.io.FileInputStream;
importjava.security.KeyStore;
importjavax.net.ssl.SSLContext;
importorg.apache.http.conn.ssl.SSLConnectionSocketFactory;
importorg.apache.http.conn.ssl.TrustSelfSignedStrategy;
importorg.apache.http.ssl.SSLContexts;
publicclassHTTPSCertifiedClientextendsHTTPSClient{
	publicHTTPSCertifiedClient(){
	}
	@Override
	publicvoidprepareCertificate()throwsException{
		//获得密匙库
		KeyStoretrustStore=KeyStore.getInstance(KeyStore.getDefaultType());
		FileInputStreaminstream=newFileInputStream(
		newFile("C:/Users/zhda6001/Downloads/software/xxx.keystore"));
		//FileInputStreaminstream=newFileInputStream(newFile("C:/Users/zhda6001/Downloads/xxx.keystore"));
		try{
			//密匙库的密码
			trustStore.load(instream,"password".toCharArray());
		}
		finally{
			instream.close();
		}
		SSLContextsslcontext=SSLContexts.custom().loadTrustMaterial(trustStore,TrustSelfSignedStrategy.INSTANCE)
		.build();
		this.connectionSocketFactory=newSSLConnectionSocketFactory(sslcontext);
	}
}

跳过认证

packagecom.darren.test.https.v45;
importjava.security.cert.CertificateException;
importjava.security.cert.X509Certificate;
importjavax.net.ssl.SSLContext;
importjavax.net.ssl.TrustManager;
importjavax.net.ssl.X509TrustManager;
importorg.apache.http.conn.ssl.SSLConnectionSocketFactory;
publicclassHTTPSTrustClientextendsHTTPSClient{
	publicHTTPSTrustClient(){
	}
	@Override
	publicvoidprepareCertificate()throwsException{
		//跳过证书验证
		SSLContextctx=SSLContext.getInstance("TLS");
		X509TrustManagertm=newX509TrustManager(){
			@Override
			publicvoidcheckClientTrusted(X509Certificate[]chain,StringauthType)throwsCertificateException{
			}
			@Override
			publicvoidcheckServerTrusted(X509Certificate[]chain,StringauthType)throwsCertificateException{
			}
			@Override
			publicX509Certificate[]getAcceptedIssuers(){
				returnnull;
			}
		}
		;
		//设置成已信任的证书
		ctx.init(null,newTrustManager[]{
			tm
		}
		,null);
		this.connectionSocketFactory=newSSLConnectionSocketFactory(ctx);
	}
}

总结

packagecom.darren.test.https.v45;
importorg.apache.http.config.Registry;
importorg.apache.http.config.RegistryBuilder;
importorg.apache.http.conn.socket.ConnectionSocketFactory;
importorg.apache.http.conn.socket.PlainConnectionSocketFactory;
importorg.apache.http.impl.client.CloseableHttpClient;
importorg.apache.http.impl.client.HttpClientBuilder;
importorg.apache.http.impl.client.HttpClients;
importorg.apache.http.impl.conn.PoolingHttpClientConnectionManager;
publicabstractclassHTTPSClientextendsHttpClientBuilder{
	privateCloseableHttpClientclient;
	protectedConnectionSocketFactoryconnectionSocketFactory;
	/**
*初始化HTTPSClient
*
*@return返回当前实例
*@throwsException
*/
	publicCloseableHttpClientinit()throwsException{
		this.prepareCertificate();
		this.regist();
		returnthis.client;
	}
	/**
*准备证书验证
*
*@throwsException
*/
	publicabstractvoidprepareCertificate()throwsException;
	/**
*注册协议和端口,此方法也可以被子类重写
*/
	protectedvoidregist(){
		//设置协议http和https对应的处理socket链接工厂的对象
		RegistrysocketFactoryRegistry=RegistryBuilder.create()
		.register("http",PlainConnectionSocketFactory.INSTANCE)
		.register("https",this.connectionSocketFactory)
		.build();
		PoolingHttpClientConnectionManagerconnManager=newPoolingHttpClientConnectionManager(socketFactoryRegistry);
		HttpClients.custom().setConnectionManager(connManager);
		//创建自定义的httpclient对象
		this.client=HttpClients.custom().setConnectionManager(connManager).build();
		//CloseableHttpClientclient=HttpClients.createDefault();
	}
}

工具类：

packagecom.darren.test.https.v45;
importjava.util.ArrayList;
importjava.util.List;
importjava.util.Map;
importjava.util.Set;
importorg.apache.http.HttpEntity;
importorg.apache.http.HttpResponse;
importorg.apache.http.NameValuePair;
importorg.apache.http.client.HttpClient;
importorg.apache.http.client.entity.UrlEncodedFormEntity;
importorg.apache.http.client.methods.HttpGet;
importorg.apache.http.client.methods.HttpPost;
importorg.apache.http.client.methods.HttpRequestBase;
importorg.apache.http.message.BasicNameValuePair;
importorg.apache.http.util.EntityUtils;
publicclassHTTPSClientUtil{
	privatestaticfinalStringDEFAULT_CHARSET="UTF-8";
	publicstaticStringdoPost(HttpClienthttpClient,Stringurl,MapparamHeader,
	MapparamBody)throwsException{
		returndoPost(httpClient,url,paramHeader,paramBody,DEFAULT_CHARSET);
	}
	publicstaticStringdoPost(HttpClienthttpClient,Stringurl,MapparamHeader,
	MapparamBody,Stringcharset)throwsException{
		Stringresult=null;
		HttpPosthttpPost=newHttpPost(url);
		setHeader(httpPost,paramHeader);
		setBody(httpPost,paramBody,charset);
		HttpResponseresponse=httpClient.execute(httpPost);
		if(response!=null){
			HttpEntityresEntity=response.getEntity();
			if(resEntity!=null){
				result=EntityUtils.toString(resEntity,charset);
			}
		}
		returnresult;
	}
	publicstaticStringdoGet(HttpClienthttpClient,Stringurl,MapparamHeader,
	MapparamBody)throwsException{
		returndoGet(httpClient,url,paramHeader,paramBody,DEFAULT_CHARSET);
	}
	publicstaticStringdoGet(HttpClienthttpClient,Stringurl,MapparamHeader,
	MapparamBody,Stringcharset)throwsException{
		Stringresult=null;
		HttpGethttpGet=newHttpGet(url);
		setHeader(httpGet,paramHeader);
		HttpResponseresponse=httpClient.execute(httpGet);
		if(response!=null){
			HttpEntityresEntity=response.getEntity();
			if(resEntity!=null){
				result=EntityUtils.toString(resEntity,charset);
			}
		}
		returnresult;
	}
	privatestaticvoidsetHeader(HttpRequestBaserequest,MapparamHeader){
		//设置Header
		if(paramHeader!=null){
			SetkeySet=paramHeader.keySet();
			for(Stringkey:keySet){
				request.addHeader(key,paramHeader.get(key));
			}
		}
	}
	privatestaticvoidsetBody(HttpPosthttpPost,MapparamBody,Stringcharset)throwsException{
		//设置参数
		if(paramBody!=null){
			Listlist=newArrayList();
			SetkeySet=paramBody.keySet();
			for(Stringkey:keySet){
				list.add(newBasicNameValuePair(key,paramBody.get(key)));
			}
			if(list.size()>0){
				UrlEncodedFormEntityentity=newUrlEncodedFormEntity(list,charset);
				httpPost.setEntity(entity);
			}
		}
	}
}

测试类：

packagecom.darren.test.https.v45;
importjava.util.HashMap;
importjava.util.Map;
importorg.apache.http.client.HttpClient;
publicclassHTTPSClientTest{
	publicstaticvoidmain(String[]args)throwsException{
		HttpClienthttpClient=null;
		//httpClient=newHTTPSTrustClient().init();
		httpClient=newHTTPSCertifiedClient().init();
		Stringurl="https://1.2.6.2:8011/xxx/api/getToken";
		//Stringurl="https://1.2.6.2:8011/xxx/api/getHealth";
		MapparamHeader=newHashMap<>();
		paramHeader.put("Accept","application/xml");
		MapparamBody=newHashMap<>();
		paramBody.put("client_id","ankur.tandon.ap@xxx.com");
		paramBody.put("client_secret","P@ssword_1");
		Stringresult=HTTPSClientUtil.doPost(httpClient,url,paramHeader,paramBody);
		//Stringresult=HTTPSClientUtil.doGet(httpsClient,url,null,null);
		System.out.println(result);
	}
}

结果：



RxitF9//7NxwXJS2cjIjYhLtvzUNvMZxxEQtGN0u07sC9ysJeIbPqte3hCjULSkoXPEUYGUVeyI9jv7/WikLrzxYKc3OSpaTSM0kCbCKphu0TB2Cn/nfzv9fMLueOWFBdyz+N0sEiI9K+0Gp7920DFEncn17wUJVmC0u2jwvM5FAjQKmilwodXZ6a0Dq+D7dQDJwVcwxBvJ2ilhyIb3pr805Vppmi9atXrVAKO0ODa006wEJFOfcgyG5p70wpJ5rrBL85vfy9WCvkd1R7j6NVjhXgH2gNimHkjEJorMjdXW2gKiUsiWsELi/XPswao7/CTWNwTnctGK8PX2ZUB0ZfA==

二、HttpURLConnection

@Controller
publicclassRestfulAction{
	@Autowired
	privateUserServiceuserService;
	//修改
	@RequestMapping(value="put/{param}",method=RequestMethod.PUT)
	public@ResponseBodyStringput(@PathVariableStringparam){
		return"put:"+param;
	}
	//新增
	@RequestMapping(value="post/{param}",method=RequestMethod.POST)
	public@ResponseBodyStringpost(@PathVariableStringparam,Stringid,Stringname){
		System.out.println("id:"+id);
		System.out.println("name:"+name);
		return"post:"+param;
	}
	//删除
	@RequestMapping(value="delete/{param}",method=RequestMethod.DELETE)
	public@ResponseBodyStringdelete(@PathVariableStringparam){
		return"delete:"+param;
	}
	//查找
	@RequestMapping(value="get/{param}",method=RequestMethod.GET)
	public@ResponseBodyStringget(@PathVariableStringparam){
		return"get:"+param;
	}
	//HttpURLConnection方式调用Restful接口
	//调用接口
	@RequestMapping(value="dealCon/{param}")
	public@ResponseBodyStringdealCon(@PathVariableStringparam){
		try{
			Stringurl="http://localhost:8080/tao-manager-web/";
			url+=(param+"/xxx");
			URLrestServiceURL=newURL(url);
			HttpURLConnectionhttpConnection=(HttpURLConnection)restServiceURL
			.openConnection();
			//param输入小写，转换成GETPOSTDELETEPUT
			httpConnection.setRequestMethod(param.toUpperCase());
			//httpConnection.setRequestProperty("Accept","application/json");
			if("post".equals(param)){
				//打开输出开关
				httpConnection.setDoOutput(true);
				//httpConnection.setDoInput(true);
				//传递参数
				Stringinput="&id="+URLEncoder.encode("abc","UTF-8");
				input+="&name="+URLEncoder.encode("啊啊啊","UTF-8");
				OutputStreamoutputStream=httpConnection.getOutputStream();
				outputStream.write(input.getBytes());
				outputStream.flush();
			}
			if(httpConnection.getResponseCode()!=200){
				thrownewRuntimeException(
				"HTTPGETRequestFailedwithErrorcode:"
				+httpConnection.getResponseCode());
			}
			BufferedReaderresponseBuffer=newBufferedReader(
			newInputStreamReader((httpConnection.getInputStream())));
			Stringoutput;
			System.out.println("OutputfromServer:\n");
			while((output=responseBuffer.readLine())!=null){
				System.out.println(output);
			}
			httpConnection.disconnect();
		}
		catch(MalformedURLExceptione){
			e.printStackTrace();
		}
		catch(IOExceptione){
			e.printStackTrace();
		}
		return"success";
	}
}

三、Spring的RestTemplate

springmvc.xml增加

controller

@Controller
publicclassRestTemplateAction{
	@Autowired
	privateRestTemplatetemplate;
	@RequestMapping("RestTem")
	public@ResponseBodyUserRestTem(Stringmethod){
		Useruser=null;
		//查找
		if("get".equals(method)){
			user=template.getForObject(
			"http://localhost:8080/tao-manager-web/get/{id}",
			User.class,"呜呜呜呜");
			//getForEntity与getForObject的区别是可以获取返回值和状态、头等信息
			ResponseEntityre=template.
			getForEntity("http://localhost:8080/tao-manager-web/get/{id}",
			User.class,"呜呜呜呜");
			System.out.println(re.getStatusCode());
			System.out.println(re.getBody().getUsername());
			//新增
		}elseif("post".equals(method)){
			HttpHeadersheaders=newHttpHeaders();
			headers.add("X-Auth-Token",UUID.randomUUID().toString());
			MultiValueMappostParameters=newLinkedMultiValueMap();
			postParameters.add("id","啊啊啊");
			postParameters.add("name","部版本");
			HttpEntity>requestEntity=newHttpEntity>(
			postParameters,headers);
			user=template.postForObject(
			"http://localhost:8080/tao-manager-web/post/aaa",requestEntity,
			User.class);
			//删除
		}elseif("delete".equals(method)){
			template.delete("http://localhost:8080/tao-manager-web/delete/{id}","aaa");
			//修改
		}elseif("put".equals(method)){
			template.put("http://localhost:8080/tao-manager-web/put/{id}",null,"bbb");
		}
		returnuser;
	}
}

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浅谈java调用Restful API接口的方式

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