Java调用Http/Https接口(6)--RestTemplate调用Http/Https接口

RestTemplate是Spring提供的用于访问Http接口的客户端，提供同步的API；在将来的Spring版本中可能会过时，将逐渐被WebClient替代。文中所使用到的软件版本：Java 1.8.0_191、SpringBoot 2.2.1.RELEASE。

1、服务端

参见Java调用Http接口(1)--编写服务端

2、调用Http接口

2.1、GET请求

    public static void get() {

        try {

            String requestPath = "http://localhost:8080/demo/httptest/getUser?userId=1000&userName=李白";

            RestTemplate template = new RestTemplate();

            //System.out.println(template.getMessageConverters());

            //第二个为StringHttpMessageConverter

            template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

            ResponseEntity<String> response = template.getForEntity(requestPath, String.class);

            System.out.println("get返回状态：" + response.getStatusCode());

            System.out.println("get返回结果：" + response.getBody());

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

2.2、POST请求(发送键值对数据）

    public static void post() {

        String requestPath = "http://localhost:8080/demo/httptest/getUser";

        RestTemplate template = new RestTemplate();

        template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

        MultiValueMap<String, String> map = new LinkedMultiValueMap <String, String>();

        map.add("userId", "1000");

        map.add("userName", "李白");

        ResponseEntity<String> response = template.postForEntity(requestPath, map, String.class);

        System.out.println("post返回状态：" + response.getStatusCode());

        System.out.println("post返回结果：" + response.getBody());

    }

2.3、POST请求(发送JSON数据）

    public static void post2() {

        String requestPath = "http://localhost:8080/demo/httptest/addUser";

        RestTemplate template = new RestTemplate();

        template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

        String param = "{\"userId\": \"1001\",\"userName\":\"杜甫\"}";

        HttpHeaders headers = new HttpHeaders();

        headers.add("Content-Type", "application/json");

        HttpEntity<String> entity =  new HttpEntity<String>(param, headers);

        ResponseEntity<String> response = template.postForEntity(requestPath, entity, String.class);

        System.out.println("post json返回状态：" + response.getStatusCode());

        System.out.println("post json返回结果：" + response.getBody());

    }

2.4、上传文件

    public static void upload() {

        String requestPath = "http://localhost:8080/demo/httptest/upload";

        RestTemplate template = new RestTemplate();

        template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

        HttpHeaders headers = new HttpHeaders();

        headers.add("Content-Type", "file/*");

        HttpEntity<FileSystemResource> entity =  new HttpEntity<FileSystemResource>(new FileSystemResource("d:/a.jpg"), headers);

        ResponseEntity<String> response = template.postForEntity(requestPath, entity, String.class);

        System.out.println("upload返回状态：" + response.getStatusCode());

        System.out.println("upload返回结果：" + response.getBody());

    }

2.5、上传文件及发送键值对数据

    public static void mulit() {

        String requestPath = "http://localhost:8080/demo/httptest/multi";

        RestTemplate template = new RestTemplate();

        template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

        MultiValueMap<String, Object> map = new LinkedMultiValueMap <String, Object>();

        map.add("param1", "参数1");

        map.add("param2", "参数2");

        map.add("file", new FileSystemResource("d:/a.jpg"));

        ResponseEntity<String> response = template.postForEntity(requestPath, map, String.class);

        System.out.println("mulit返回状态：" + response.getStatusCode());

        System.out.println("mulit返回结果：" + response.getBody());

    }

2.6、完整例子

package com.inspur.demo.http.client;

import java.nio.charset.Charset;

import org.springframework.core.io.FileSystemResource;

import org.springframework.http.HttpEntity;

import org.springframework.http.HttpHeaders;

import org.springframework.http.ResponseEntity;

import org.springframework.http.converter.StringHttpMessageConverter;

import org.springframework.util.LinkedMultiValueMap;

import org.springframework.util.MultiValueMap;

import org.springframework.web.client.RestTemplate;

/**

 *

 * 通过RestTemplate调用Http接口

 *

 */

public class RestTemplateCase {

    /**

     *  GET请求

     */

    public static void get() {

        try {

            String requestPath = "http://localhost:8080/demo/httptest/getUser?userId=1000&userName=李白";

            RestTemplate template = new RestTemplate();

            //System.out.println(template.getMessageConverters());

            //第二个为StringHttpMessageConverter

            template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

            ResponseEntity<String> response = template.getForEntity(requestPath, String.class);

            System.out.println("get返回状态：" + response.getStatusCode());

            System.out.println("get返回结果：" + response.getBody());

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

    /**

     *  POST请求(发送键值对数据)

     */

    public static void post() {

        String requestPath = "http://localhost:8080/demo/httptest/getUser";

        RestTemplate template = new RestTemplate();

        template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

        MultiValueMap<String, String> map = new LinkedMultiValueMap <String, String>();

        map.add("userId", "1000");

        map.add("userName", "李白");

        ResponseEntity<String> response = template.postForEntity(requestPath, map, String.class);

        System.out.println("post返回状态：" + response.getStatusCode());

        System.out.println("post返回结果：" + response.getBody());

    }

    /**

     *  POST请求(发送json数据)

     */

    public static void post2() {

        String requestPath = "http://localhost:8080/demo/httptest/addUser";

        RestTemplate template = new RestTemplate();

        template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

        String param = "{\"userId\": \"1001\",\"userName\":\"杜甫\"}";

        HttpHeaders headers = new HttpHeaders();

        headers.add("Content-Type", "application/json");

        HttpEntity<String> entity =  new HttpEntity<String>(param, headers);

        ResponseEntity<String> response = template.postForEntity(requestPath, entity, String.class);

        System.out.println("post json返回状态：" + response.getStatusCode());

        System.out.println("post json返回结果：" + response.getBody());

    }

    /**

     * 上传文件

     */

    public static void upload() {

        String requestPath = "http://localhost:8080/demo/httptest/upload";

        RestTemplate template = new RestTemplate();

        template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

        HttpHeaders headers = new HttpHeaders();

        headers.add("Content-Type", "file/*");

        HttpEntity<FileSystemResource> entity =  new HttpEntity<FileSystemResource>(new FileSystemResource("d:/a.jpg"), headers);

        ResponseEntity<String> response = template.postForEntity(requestPath, entity, String.class);

        System.out.println("upload返回状态：" + response.getStatusCode());

        System.out.println("upload返回结果：" + response.getBody());

    }

    /**

     * 上传文件及发送键值对数据

     */

    public static void mulit() {

        String requestPath = "http://localhost:8080/demo/httptest/multi";

        RestTemplate template = new RestTemplate();

        template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

        MultiValueMap<String, Object> map = new LinkedMultiValueMap <String, Object>();

        map.add("param1", "参数1");

        map.add("param2", "参数2");

        map.add("file", new FileSystemResource("d:/a.jpg"));

        ResponseEntity<String> response = template.postForEntity(requestPath, map, String.class);

        System.out.println("mulit返回状态：" + response.getStatusCode());

        System.out.println("mulit返回结果：" + response.getBody());

    }

    public static void main(String[] args) {

        get();

        post();

        post2();

        upload();

        mulit();

    }

}

3、调用Https接口

与调用Http接口不一样的部分主要在设置ssl部分，设置方法是扩展SimpleClientHttpRequestFactory并在prepareConnection方法中进行ssl的设置；ssl的设置与HttpsURLConnection很相似(参见Java调用Http/Https接口(2)--HttpURLConnection/HttpsURLConnection调用Http/Https接口)；下面用GET请求来演示ssl的设置，其他调用方式类似。

package com.inspur.demo.http.client;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.net.HttpURLConnection;

import java.nio.charset.Charset;

import java.security.KeyStore;

import java.security.cert.CertificateException;

import java.security.cert.X509Certificate;

import javax.net.ssl.HostnameVerifier;

import javax.net.ssl.HttpsURLConnection;

import javax.net.ssl.KeyManager;

import javax.net.ssl.KeyManagerFactory;

import javax.net.ssl.SSLContext;

import javax.net.ssl.SSLSession;

import javax.net.ssl.TrustManager;

import javax.net.ssl.TrustManagerFactory;

import javax.net.ssl.X509TrustManager;

import org.springframework.http.ResponseEntity;

import org.springframework.http.client.SimpleClientHttpRequestFactory;

import org.springframework.http.converter.StringHttpMessageConverter;

import org.springframework.web.client.RestTemplate;

import com.inspur.demo.common.util.FileUtil;

/**

 * 通过RestTemplate调用Https接口

 */

public class RestTemplateHttpsCase {

    public static void main(String[] args) {

        try {

            /*

             * 请求有权威证书的地址

             */

            String requestPath = "https://www.baidu.com/";

            RestTemplate template = new RestTemplate();

            template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

            ResponseEntity<String> response = template.getForEntity(requestPath, String.class);

            System.out.println("get1返回结果：" + response.getBody());

            /*

             * 请求自定义证书的地址

             */

            //获取信任证书库

            KeyStore trustStore = getkeyStore("jks", "d:/temp/cacerts", "123456");

            //不需要客户端证书

            requestPath = "https://10.40.x.x:9010/zsywservice";

            template = new RestTemplate(new HttpsClientRequestFactory(trustStore));

            template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

            response = template.getForEntity(requestPath, String.class);

            System.out.println("get2返回结果：" + response.getBody());

            //需要客户端证书

            requestPath = "https://10.40.x.x:9016/zsywservice";

            KeyStore keyStore = getkeyStore("pkcs12", "d:/client.p12", "123456");

            template = new RestTemplate(new HttpsClientRequestFactory(keyStore, "123456", trustStore));

            template.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("UTF-8")));

            response = template.getForEntity(requestPath, String.class);

            System.out.println("get3返回结果：" + response.getBody());

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

    /**

     * 获取证书

     * @return

     */

    private static KeyStore getkeyStore(String type, String filePath, String password) {

        KeyStore keySotre = null;

        FileInputStream in = null;

        try {

            keySotre = KeyStore.getInstance(type);

            in = new FileInputStream(new File(filePath));

            keySotre.load(in, password.toCharArray());

        } catch (Exception e) {

            e.printStackTrace();

        } finally {

            FileUtil.close(in);

        }

        return keySotre;

    }

    /**

     * 扩展SimpleClientHttpRequestFactory以支持Https

     */

    private static class HttpsClientRequestFactory extends SimpleClientHttpRequestFactory {

        private KeyStore keyStore;

        private String keyStorePassword;

        private KeyStore trustStore;

        public HttpsClientRequestFactory(KeyStore keyStore, String keyStorePassword, KeyStore trustStore) {

            this.keyStore = keyStore;

            this.keyStorePassword = keyStorePassword;

            this.trustStore = trustStore;

        }

        public HttpsClientRequestFactory(KeyStore trustStore) {

            this.trustStore = trustStore;

        }

        @Override

        protected void prepareConnection(HttpURLConnection connection, String httpMethod) throws IOException {

            try {

                if (!(connection instanceof HttpsURLConnection)) {

                    throw new RuntimeException("An instance of HttpsURLConnection is expected");

                }

                HttpsURLConnection httpsConnection = (HttpsURLConnection) connection;

                KeyManager[] keyManagers = null;

                TrustManager[] trustManagers = null;

                if (this.keyStore != null) {

                    KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance("SunX509");

                    keyManagerFactory.init(keyStore, keyStorePassword.toCharArray());

                    keyManagers = keyManagerFactory.getKeyManagers();

                }

                if (this.trustStore != null) {

                    TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance("SunX509");

                    trustManagerFactory.init(trustStore);

                    trustManagers = trustManagerFactory.getTrustManagers();

                } else {

                    trustManagers = new TrustManager[] { new DefaultTrustManager()};

                }

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

                sslContext.init(keyManagers, trustManagers, null);

                httpsConnection.setSSLSocketFactory(sslContext.getSocketFactory());

                //验证URL的主机名和服务器的标识主机名是否匹配

                httpsConnection.setHostnameVerifier(new HostnameVerifier() {

                    @Override

                    public boolean verify(String s, SSLSession sslSession) {

                        //if ("xxx".equals(hostname)) {

                        //    return true;

                        //} else {

                        //    return false;

                        //}

                        return true;

                    }

                });

                super.prepareConnection(httpsConnection, httpMethod);

            } catch (Exception e) {

                e.printStackTrace();

            }

        }

    }

    private static final class DefaultTrustManager implements 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;

        }

    }

}

4、AsyncRestTemplate

该模板已过时，建议使用WebClient替代。

巴特西