浅谈java调用Restful API接口的方式-eolink官网

浅谈java调用Restful API接口的方式

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

package com.darren.test.https.v42;

import java.io.File;

import java.io.FileInputStream;

import java.security.KeyStore;

import org.apache.http.conn.ssl.SSLSocketFactory;

public class HTTPSCertifiedClient extends HTTPSClient {

public HTTPSCertifiedClient() {

}

@Override

public void prepareCertificate() throws Exception {

// 获得密匙库

KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());

FileInputStream instream = new FileInputStream(

new File("C:/Users/zhda6001/Downloads/software/xxx.keystore"));

// FileInputStream instream = new FileInputStream(new File("C:/Users/zhda6001/Downloads/xxx.keystore"));

// 密匙库的密码

trustStore.load(instream, "password".toCharArray());

// 注册密匙库

this.socketFactory = new SSLSocketFactory(trustStore);

// 不校验域名

socketFactory.setHostnameVerihttp://fier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);

}

跳过认证

在准备证书阶段选择的是跳过认证

package com.darren.test.https.v42;

import java.security.cert.CertificateException;

import java.security.cert.X509Certificate;

import javax.net.ssl.SSLContext;

import javax.net.ssl.TrustManager;

import javax.net.ssl.X509TrustManager;

import org.apache.http.conn.ssl.SSLSocketFactory;

public class HTTPSTrustClient extends HTTPSClient {

public HTTPSTrustClient() {

}

@Override

public void prepareCertificate() throws Exception {

// 跳过证书验证

SSLContext ctx = SSLContext.getInstance("TLS");

X509TrustManager tm = new X509TrustManager() {

@Override

public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {

}

@Override

public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {

}

@Override

public X509Certificate[] getAcceptedIssuers() {

return null;

}

;

// 设置成已信任的证书

ctx.init(null, new TrustManager[] {

}

, null);

// 穿件SSL socket 工厂，并且设置不检查host名称

this.socketFactory = new SSLSocketFactory(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。

package com.darren.test.https.v42;

import org.apache.http.conn.ClientConnectionManager;

import org.apache.http.conn.scheme.Scheme;

import org.apache.http.conn.scheme.SchemeRegistry;

import org.apache.http.conn.ssl.SSLSocketFactory;

import org.apache.http.impl.client.DefaultHttpClient;

public abstract class HTTPSClient extends DefaultHttpClient {

protected SSLSocketFactory socketFactory;

/**

* 初始化HTTPSClient

* @return 返回当前实例

* @throws Exception

public HTTPSClient init() throws Exception {

this.prepareCertificate();

this.regist();

return this;

}

/**

* 准备证书验证

* @throws Exception

public abstract void prepareCertificate() throws Exception;

/**

* 注册协议和端口, 此方法也可以被子类重写

protected void regist() {

ClientConnectionManager ccm = this.getConnectionManager();

SchemeRegistry sr = ccm.getSchemeRegistry();

sr.register(new Scheme("https", 443, socketFactory));

}

下边是工具类

package com.darren.test.https.v42;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.Set;

import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.NameValuePair;

import org.apache.http.client.entity.UrlEncodedFormEntity;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.client.methods.HttpRequestBase;

import org.apache.http.message.BasicNameValuePair;

import org.apache.http.util.EntityUtils;

public class HTTPSClientUtil {

private static final String DEFAULT_CHARSET = "UTF-8";

public static String doPost(HTTPSClient httpsClient, String url, Map paramHeader,

Map paramBody) throws Exception {

return doPost(httpsClient, url, paramHeader, paramBody, DEFAULT_CHARSET);

}

public static String doPost(HTTPSClient httpsClient, String url, Map paramHeader,

Map paramBody, String charset) throws Exception {

String result = null;

HttpPost httpPost = new HttpPost(url);

setHeader(httpPost, paramHeader);

setBody(httpPost, paramBody, charset);

HttpResponse response = httpsClient.execute(httpPost);

if (response != null) {

HttpEntity resEntity = response.getEntity();

if (resEntity != null) {

result = EntityUtils.toString(resEntity, charset);

}

return result;

}

public static String doGet(HTTPSClient httpsClient, String url, Map paramHeader,

Map paramBody) throws Exception {

return doGet(httpsClient, url, paramHeader, paramBody, DEFAULT_CHARSET);

}

public static String doGet(HTTPSClient httpsClient, String url, Map paramHeader,

Map paramBody, String charset) throws Exception {

String result = null;

HttpGet httpGet = new HttpGet(url);

setHeader(httpGet, paramHeader);

HttpResponse response = httpsClient.execute(httpGet);

if (response != null) {

HttpEntity resEntity = response.getEntity();

if (resEntity != null) {

result = EntityUtils.toString(resEntity, charset);

}

return result;

}

private static void setHeader(HttpRequestBase request, Map paramHeader) {

// 设置Header

if (paramHeader != null) {

Set keySet = paramHeader.keySet();

for (String key : keySet) {

request.addHeader(key, paramHeader.get(key));

}

private static void setBody(HttpPost httpPost, Map paramBody, String charset) throws Exception {

// 设置参数

if (paramBody != null) {

List list = new ArrayList();

Set keySet = paramBody.keySet();

for (String key : keySet) {

list.add(new BasicNameValuePair(key, paramBody.get(key)));

}

if (list.size() > 0) {

UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list, charset);

httpPost.setEntity(entity);

}

然后是测试类：

package com.darren.test.https.v42;

import java.util.HashMap;

import java.util.Map;

public class HTTPSClientTest {

public static void main(String[] args) throws Exception {

HTTPSClient httpsClient = null;

httpsClient = new HTTPSTrustClient().init();

//httpsClient = new HTTPSCertifiedClient().init();

String url = "https://1.2.6.2:8011/xxx/api/getToken";

//String url = "https://1.2.6.2:8011/xxx/api/getHealth";

Map paramHeader = new HashMap<>();

//paramHeader.put("Content-Type", "application/json");

paramHeader.put("Accept", "application/xml");

Map paramBody = new HashMap<>();

paramBody.put("client_id", "ankur.tandon.ap@xxx.com");

paramBody.put("client_secret", "P@ssword_1");

String result = HTTPSClientUtil.doPost(httpsClient, url, paramHeader, paramBody);

//String result = 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

package com.darren.test.https.v45;

import java.io.File;

import java.io.FileInputStream;

import java.security.KeyStore;

import javax.net.ssl.SSLContext;

import org.apache.http.conn.ssl.SSLConnectionSocketFactory;

import org.apache.http.conn.ssl.TrustSelfSignedStrategy;

import org.apache.http.ssl.SSLContexts;

public class HTTPSCertifiedClient extends HTTPSClient {

public HTTPSCertifiedClient() {

}

@Override

public vohttp://id prepareCertificate() throws Exception {

// 获得密匙库

KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());

FileInputStream instream = new FileInputStream(

new File("C:/Users/zhda6001/Downloads/software/xxx.keystore"));

// FileInputStream instream = new FileInputStream(new File("C:/Users/zhda6001/Downloads/xxx.keystore"));

try {

// 密匙库的密码

trustStore.load(instream, "password".toCharArray());

}

finally {

instream.close();

}

SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(trustStore, TrustSelfSignedStrategy.INSTANCE)

.build();

this.connectionSocketFactory = new SSLConnectionSocketFactory(sslcontext);

}

跳过认证

package com.darren.test.https.v45;

import java.security.cert.CertificateException;

import java.security.cert.X509Certificate;

import javax.net.ssl.SSLContext;

import javax.net.ssl.TrustManager;

import javax.net.ssl.X509TrustManager;

import org.apache.http.conn.ssl.SSLConnectionSocketFactory;

public class HTTPSTrustClient extends HTTPSClient {

public HTTPSTrustClient() {

}

@Override

public void prepareCertificate() throws Exception {

// 跳过证书验证

SSLContext ctx = SSLContext.getInstance("TLS");

X509TrustManager tm = new X509TrustManager() {

@Override

public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {

}

@Override

public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {

}

@Override

public X509Certificate[] getAcceptedIssuers() {

return null;

}

;

// 设置成已信任的证书

ctx.init(null, new TrustManager[] {

}

, null);

this.connectionSocketFactory = new SSLConnectionSocketFactory(ctx);

}

总结

package com.darren.test.https.v45;

import org.apache.http.config.Registry;

import org.apache.http.config.RegistryBuilder;

import org.apache.http.conn.socket.ConnectionSocketFactory;

import org.apache.http.conn.socket.PlainConnectionSocketFactory;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClientBuilder;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;

public abstract class HTTPSClient extends HttpClientBuilder {

private CloseableHttpClient client;

protected ConnectionSocketFactory connectionSocketFactory;

/**

* 初始化HTTPSClient

* @return 返回当前实例

* @throws Exception

public CloseableHttpClient init() throws Exception {

this.prepareCertificate();

this.regist();

return this.client;

}

/**

* 准备证书验证

* @throws Exception

public abstract void prepareCertificate() throws Exception;

/**

* 注册协议和端口, 此方法也可以被子类重写

protected void regist() {

// 设置协议http和https对应的处理socket链接工厂的对象

Registry socketFactoryRegistry = RegistryBuilder.create()

OmHBJfeRw.register("http", PlainConnectionSocketFactory.INSTANCE)

.register("https", this.connectionSocketFactory)

.build();

PoolingHttpClientConnectionManager connManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry);

HttpClients.custom().setConnectionManager(connManager);

// 创建自定义的httpclient对象

this.client = HttpClients.custom().setConnectionManager(connManager).build();

// CloseableHttpClient client = HttpClients.createDefault();

}

工具类：

package com.darren.test.https.v45;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.Set;

import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.NameValuePair;

import org.apache.http.client.HttpClient;

import org.apache.http.client.entity.UrlEncodedFormEntity;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.client.methods.HttpRequestBase;

import org.apache.http.message.BasicNameValuePair;

import org.apache.http.util.EntityUtils;

public class HTTPSClientUtil {

private static final String DEFAULT_CHARSET = "UTF-8";

public static String doPost(HttpClient httpClient, String url, Map paramHeader,

Map paramBody) throws Exception {

return doPost(httpClient, url, paramHeader, paramBody, DEFAULT_CHARSET);

}

public static String doPost(HttpClient httpClient, String url, Map paramHeader,

Map paramBody, String charset) throws Exception {

String result = null;

HttpPost httpPost = new HttpPost(url);

setHeader(httpPost, paramHeader);

setBody(httpPost, paramBody, charset);

HttpResponse response = httpClient.execute(httpPost);

if (response != null) {

HttpEntity resEntity = response.getEntity();

if (resEntity != null) {

result = EntityUtils.toString(resEntity, charset);

}

return result;

}

public static String doGet(HttpClient httpClient, String url, Map paramHeader,

Map paramBody) throws Exception {

return doGet(httpClient, url, paramHeadhttp://er, paramBody, DEFAULT_CHARSET);

}

public static String doGet(HttpClient httpClient, String url, Map paramHeader,

Map paramBody, String charset) throws Exception {

String result = null;

HttpGet httpGet = new HttpGet(url);

setHeader(httpGet, paramHeader);

HttpResponse response = httpClient.execute(httpGet);

if (response != null) {

HttpEntity resEntity = response.getEntity();

if (resEntity != null) {

result = EntityUtils.toString(resEntity, charset);

}

return result;

}

private static void setHeader(HttpRequestBase request, Map paramHeader) {

// 设置Header

if (paramHeader != null) {

Set keySet = paramHeader.keySet();

for (String key : keySet) {

request.addHeader(key, paramHeader.get(key));

}

private static void setBody(HttpPost httpPost, Map paramBody, String charset) throws Exception {

// 设置参数

if (paramBody != null) {

List list = new ArrayList();

Set keySet = paramBody.keySet();

for (String key : keySet) {

list.add(new BasicNameValuePair(key, paramBody.get(key)));

}

if (list.size() > 0) {

UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list, charset);

httpPost.setEntity(entity);

}

测试类：

package com.darren.test.https.v45;

import java.util.HashMap;

import java.util.Map;

import org.apache.http.client.HttpClient;

public class HTTPSClientTest {

public static void main(String[] args) throws Exception {

HttpClient httpClient = null;

//httpClient = new HTTPSTrustClient().init();

httpClient = new HTTPSCertifiedClient().init();

String url = "https://1.2.6.2:8011/xxx/api/getToken";

//String url = "https://1.2.6.2:8011/xxx/api/getHealth";

Map paramHeader = new HashMap<>();

paramHeader.put("Accept", "application/xml");

Map paramBody = new HashMap<>();

paramBody.put("client_id", "ankur.tandon.ap@xxx.com");

paramBody.put("client_secret", "P@ssword_1");

String result = HTTPSClientUtil.doPost(httpClient, url, paramHeader, paramBody);

//String result = HTTPSClientUtil.doGet(httpsClient, url, null, null);

System.out.println(result);

}

结果：

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

二、HttpURLConnection

@Controller

public class RestfulAction {

@Autowired

private UserService userService;

// 修改

@RequestMapping(value = "put/{param}", method = RequestMethod.PUT)

public @ResponseBody String put(@PathVariable String param) {

return "put:" + param;

}

// 新增

@RequestMapping(value = "post/{param}", method = RequestMethod.POST)

public @ResponseBody String post(@PathVariable String param,String id,String name) {

System.out.println("id:"+id);

System.out.println("name:"+name);

return "post:" + param;

}

// 删除

@RequestMapping(value = "delete/{param}", method = RequestMethod.DELETE)

public @ResponseBody String delete(@PathVariable String param) {

return "delete:" + param;

}

// 查找

@RequestMapping(value = "get/{param}", method = RequestMethod.GET)

public @ResponseBody String get(@PathVariable String param) {

return "get:" + param;

}

// HttpURLConnection 方式调用Restful接口

// 调用接口

@RequestMapping(value = "dealCon/{param}")

public @ResponseBody String dealCon(@PathVariable String param) {

try {

String url = "http://localhost:8080/tao-manager-web/";

url+=(param+"/xxx");

URL restServiceURL = new URL(url);

HttpURLConnection httpConnection = (HttpURLConnection) restServiceURL

.openConnection();

//param 输入小写，转换成 GET POST DELETE PUT

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

String input = "&id="+ URLEncoder.encode("abc", "UTF-8");

input+="&name="+ URLEncoder.encode("啊啊啊", "UTF-8");

OutputStream outputStream = httpConnection.getOutputStream();

outputStream.write(input.getBytes());

outputStream.flush();

}

if (httpConnection.getResponseCode() != 200) {

throw new RuntimeException(

"HTTP GET Request Failed with Error code : "

+ httpConnection.getResponseCode());

}

BufferedReader responseBuffer = new BufferedReader(

new InputStreamReader((httpConnection.getInputStream())));

String output;

System.out.println("Output from Server: \n");

while ((output = responseBuffer.readLine()) != null) {

System.out.println(output);

}

httpConnection.disconnect();

}

catch (MalformedURLException e) {

e.printStackTrace();

}

catch (IOException e) {

e.printStackTrace();

}

return "success";

}

三、Spring的RestTemplate

springmvc.xml增加

class="org.springframework.http.client.SimpleClientHttpRequestFactory">

controller

@Controller

public class RestTemplateAction {

@Autowired

private RestTemplate template;

@RequestMapping("RestTem")

public @ResponseBody User RestTem(String method) {

User user = 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

ResponseEntity re = 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

} else if ("post".equals(method)) {

HttpHeaders headers = new HttpHeaders();

headers.add("X-Auth-Token", UUID.randomUUID().toString());

MultiValueMap postParameters = new LinkedMultiValueMap();

postParameters.add("id", "啊啊啊");

postParameters.add("name", "部版本");

HttpEntity> requestEntity = new HttpEntity>(

postParameters, headers);

user = template.postForObject(

"http://localhost:8080/tao-manager-web/post/aaa", requestEntity,

User.class);

//删除

} else if ("delete".equals(method)) {

template.delete("http://localhost:8080/tao-manager-web/delete/{id}","aaa");

//修改

} else if ("put".equals(method)) {

template.put("http://localhost:8080/tao-manager-web/put/{id}",null,"bbb");

}

return user;

}

以上就是本文关于浅谈java调用Restful API接口的方式的全部内容，希望对大家有所帮助。感兴趣的朋友可以继续参阅本站其他Java相关专题，如有不足之处，欢迎留言指出。感谢朋友们对本站的支持！

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