小编给大家分享一下java中如何调用Restful API接口，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
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.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
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[] {
tm
}
, 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<String, String> paramHeader,
Map<String, String> paramBody) throws Exception {
return doPost(httpsClient, url, paramHeader, paramBody, DEFAULT_CHARSET);
}
public static String doPost(HTTPSClient httpsClient, String url, Map<String, String> paramHeader,
Map<String, String> 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<String, String> paramHeader,
Map<String, String> paramBody) throws Exception {
return doGet(httpsClient, url, paramHeader, paramBody, DEFAULT_CHARSET);
}
public static String doGet(HTTPSClient httpsClient, String url, Map<String, String> paramHeader,
Map<String, String> 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<String, String> paramHeader) {
// 设置Header
if (paramHeader != null) {
Set<String> keySet = paramHeader.keySet();
for (String key : keySet) {
request.addHeader(key, paramHeader.get(key));
}
}
}
private static void setBody(HttpPost httpPost, Map<String, String> paramBody, String charset) throws Exception {
// 设置参数
if (paramBody != null) {
List<NameValuePair> list = new ArrayList<NameValuePair>();
Set<String> 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<String, String> paramHeader = new HashMap<>();
//paramHeader.put("Content-Type", "application/json");
paramHeader.put("Accept", "application/xml");
Map<String, String> 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：
<?xml version="1.0" encoding="utf-8"?> <token>jkf8RL0sw+Skkflj8RbKI5hP1bEQK8PrCuTZPpBINqMYKRMxY1kWCjmCfT191Zpp88VV1aGHW8oYNWjEYS0axpLuGAX89ejCoWNbikCc1UvfyesXHLktcJqyUFiVjevhrEQxJPHncLQYWP+Xse5oD9X8vKFKk7InNTMRzQK7YBTZ/e3U7gswM/5cvAHFl6o9rEq9cWPXavZNohyvnXsohSzDo+BXAtXxa1xpEDLy/8h/UaP4n4dlZDJJ3B8t1Xh+CRRIoMOPxf7c5wKhHtOkEOeXW+xoPQKKSx5CKWwJpPuGIIFWF/PaqWg+JUOsVT7QGdPv8PMWJ9DwEwjTdxguDg==</token>
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 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"));
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[] {
tm
}
, 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<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory>create()
.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<String, String> paramHeader,
Map<String, String> paramBody) throws Exception {
return doPost(httpClient, url, paramHeader, paramBody, DEFAULT_CHARSET);
}
public static String doPost(HttpClient httpClient, String url, Map<String, String> paramHeader,
Map<String, String> 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<String, String> paramHeader,
Map<String, String> paramBody) throws Exception {
return doGet(httpClient, url, paramHeader, paramBody, DEFAULT_CHARSET);
}
public static String doGet(HttpClient httpClient, String url, Map<String, String> paramHeader,
Map<String, String> 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<String, String> paramHeader) {
// 设置Header
if (paramHeader != null) {
Set<String> keySet = paramHeader.keySet();
for (String key : keySet) {
request.addHeader(key, paramHeader.get(key));
}
}
}
private static void setBody(HttpPost httpPost, Map<String, String> paramBody, String charset) throws Exception {
// 设置参数
if (paramBody != null) {
List<NameValuePair> list = new ArrayList<NameValuePair>();
Set<String> 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<String, String> paramHeader = new HashMap<>();
paramHeader.put("Accept", "application/xml");
Map<String, String> 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：
<?xml version="1.0" encoding="utf-8"?> <token>RxitF9//7NxwXJS2cjIjYhLtvzUNvMZxxEQtGN0u07sC9ysJeIbPqte3hCjULSkoXPEUYGUVeyI9jv7/WikLrzxYKc3OSpaTSM0kCbCKphu0TB2Cn/nfzv9fMLueOWFBdyz+N0sEiI9K+0Gp7920DFEncn17wUJVmC0u2jwvM5FAjQKmilwodXZ6a0Dq+D7dQDJwVcwxBvJ2ilhyIb3pr805Vppmi9atXrVAKO0ODa006wEJFOfcgyG5p70wpJ5rrBL85vfy9WCvkd1R7j6NVjhXgH2gNimHkjEJorMjdXW2gKiUsiWsELi/XPswao7/CTWNwTnctGK8PX2ZUB0ZfA==</token>
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
<!-- 配置RestTemplate --> <!--Http client Factory --> <bean id="httpClientFactory" class="org.springframework.http.client.SimpleClientHttpRequestFactory"> <property name="connectTimeout" value="10000" /> <property name="readTimeout" value="10000" /> </bean> <!--RestTemplate --> <bean id="restTemplate" class="org.springframework.web.client.RestTemplate"> <constructor-arg ref="httpClientFactory" /> </bean>
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<User> 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<String, String> postParameters = new LinkedMultiValueMap<String, String>();
postParameters.add("id", "啊啊啊");
postParameters.add("name", "部版本");
HttpEntity<MultiValueMap<String, String>> requestEntity = new HttpEntity<MultiValueMap<String, String>>(
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;
}
}以上是“java中如何调用Restful API接口”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注亿速云行业资讯频道！
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