java远程调用接口、URL的方式

2023-09-17 16:13

短信预约 -IT技能 免费直播动态提醒

一：httpUrlConnection

1.获取HttpURLConnection连接对象

       public static HttpURLConnection getHttpURLConnection(String url){        try {            //建立连接            URL httpUrl = new URL(url);            HttpURLConnection urlConnection =(HttpURLConnection)httpUrl.openConnection();            //向文件所在服务器发送标识信息,模拟浏览器            urlConnection.setRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36");            return urlConnection;        } catch (IOException e) {            e.printStackTrace();            return null;        }    }

2.远程调用代码

    public void accessLoginUrl(){        //远程调用接口的url        String loginUrl = "http://localhost:8989/login/doLogin";        OutputStream outputStream = null;        InputStream inputStream = null;        ByteArrayOutputStream byteArrayOutputStream = null;        try {            //获取压测接口的userTicket            URL url = new URL(loginUrl);            HttpURLConnection connection = (HttpURLConnection) url.openConnection();            //登录是post请求            connection.setRequestMethod("POST");            //post请求需要设置接口返回的数据，所以设置为true            connection.setDoOutput(true);            //参数userId和密码            String param = "mobile=" + 13100000000000L + "&password=" + "123456";            //获取登录接口返回的流文件            outputStream = connection.getOutputStream();            outputStream.write(param.getBytes(StandardCharsets.UTF_8));            outputStream.flush();            inputStream = connection.getInputStream();            byteArrayOutputStream = new ByteArrayOutputStream();            byte[] buffer = new byte[1024];            int len = 0;            while ((len = inputStream.read(buffer)) >= 0){                byteArrayOutputStream.write(buffer, 0, len);            }            //获取响应结果            String response = byteArrayOutputStream.toString();            ObjectMapper objectMapper = new ObjectMapper();            RespBean respBean = objectMapper.readValue(response, RespBean.class);            String userTicket = (String) respBean.getObject();            System.out.println("远程调用接口的返回值"+userTicket);            //userTicket就是远程接口返回的值        } catch (IOException e) {            e.printStackTrace();        } finally {            if(byteArrayOutputStream != null){                try {                    byteArrayOutputStream.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if(outputStream != null){                try {                    outputStream.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }    }

二：RestTemplate

2.1 什么是RestTemplate

spring 框架提供的 RestTemplate 类可用于在应用中调用 rest 服务，它简化了与 http 服务的通信方式，统一了 RESTful 的标准，封装了 http 链接，我们只需要传入 url 及返回值类型即可。相较于之前常用的 HttpClient，RestTemplate 是一种更优雅的调用 RESTful 服务的方式。
在 Spring 应用程序中访问第三方 REST 服务与使用 Spring RestTemplate 类有关。RestTemplate 类的设计原则与许多其他 Spring 模板类(例如 JdbcTemplate、JmsTemplate)相同，为执行复杂任务提供了一种具有默认行为的简化方法。
RestTemplate 默认依赖 JDK 提供 http 连接的能力（HttpURLConnection），如果有需要的话也可以通过 setRequestFactory 方法替换为例如 Apache HttpComponents、Netty 或 OkHttp 等其它 HTTP library。
考虑到 RestTemplate 类是为调用 REST 服务而设计的，因此它的主要方法与 REST 的基础紧密相连就不足为奇了，后者是 HTTP 协议的方法:HEAD、GET、POST、PUT、DELETE 和 OPTIONS。例如，RestTemplate 类具有 headForHeaders()、getForObject()、postForObject()、put()和 delete()等方法。

2.2 配置RestTemplate

@Configurationpublic class RestTemplateConfig {    @Bean    public RestTemplate restTemplate(){        SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();        //解决401报错时，报java.net.HttpRetryException: cannot retry due to server authentication, in streaming mode        requestFactory.setOutputStreaming(false);        RestTemplate restTemplate = new RestTemplate(requestFactory);        restTemplate.setErrorHandler(new RtErrorHandler());        return restTemplate;    }        @Bean    public ClientHttpRequestFactory simpleClientHttpRequestFactory() {        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();        factory.setReadTimeout(5000);        factory.setConnectTimeout(15000);        return factory;    }

2.2 RestTemplate 添加请求头headers和请求体body

        HttpHeaders header = new HttpHeaders();        header.add("X-Consumer-Third-User-Id", "X-Consumer-Third-User-Id");        header.add("X-Consumer-Third-User-Name", "X-Consumer-Third-User-Name");        header.set("Authorization", "authorization");        HttpEntity<AssetProcessVo> httpEntity = new HttpEntity<>(assetProcessVo, header);

header 为需要设置的请求头
AssetProcessVo为需要远程调用接口传递的参数

2.3 示例代码

    public void accessLoginUrl(){        HttpHeaders header = new HttpHeaders();        header.add("X-Consumer-Third-User-Id", "X-Consumer-Third-User-Id");        header.add("X-Consumer-Third-User-Name", "X-Consumer-Third-User-Name");        header.set("Authorization", "authorization");        HttpEntity<AssetProcessVo> httpEntity = new HttpEntity<>(assetProcessVo, header);        ResponseEntity<ByteArrayOutputStream> exchange;        try {            //保存案件名称后，启动工作流            exchange = restTemplate.exchange(url, HttpMethod.POST, httpEntity, ByteArrayOutputStream.class);            if (exchange.getStatusCodeValue() == 200) {                String response = byteArrayOutputStream.toString();                ObjectMapper objectMapper = new ObjectMapper();                RespBean respBean = objectMapper.readValue(response, RespBean.class);            }        } catch (RestClientException e) {            e.printStackTrace();        }

三：HttpClient

3.1 导入依赖

    org.apache.httpcomponents    httpclient    4.5.3

3.2 使用方法

1，创建HttpClient对象；
2，指定请求URL，并创建请求对象，如果是get请求则创建HttpGet对象，post则创建HttpPost对象；
3，如果请求带有参数，对于get请求可直接在URL中加上参数请求，或者使用setParam(HetpParams params)方法设置参数，对于HttpPost请求，可使用setParam(HetpParams params)方法或者调用setEntity(HttpEntity entity)方法设置参数；
4，调用httpClient的execute(HttpUriRequest request)执行请求，返回结果是一个response对象；
5，通过response的getHeaders(String name)或getAllHeaders()可获得请求头部信息，getEntity()方法获取HttpEntity对象，该对象包装了服务器的响应内容。

3.3 代码实现

package com.cnzz.demo.remote.rpc; import com.alibaba.fastjson.JSONObject;import org.apache.commons.httpclient.*;import org.apache.commons.httpclient.methods.GetMethod;import org.apache.commons.httpclient.methods.PostMethod;import org.apache.commons.httpclient.params.HttpMethodParams; import java.io.IOException;  public class HttpClientUtil {         public static String doGet(String url, String charset) {        //1.生成HttpClient对象并设置参数        HttpClient httpClient = new HttpClient();        //设置Http连接超时为5秒        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(5000);        //2.生成GetMethod对象并设置参数        GetMethod getMethod = new GetMethod(url);        //设置get请求超时为5秒        getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 5000);        //设置请求重试处理，用的是默认的重试处理：请求三次        getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler());        String response = "";        //3.执行HTTP GET 请求        try {            int statusCode = httpClient.executeMethod(getMethod);            //4.判断访问的状态码            if (statusCode != HttpStatus.SC_OK) {                System.err.println("请求出错：" + getMethod.getStatusLine());            }            //5.处理HTTP响应内容            //HTTP响应头部信息，这里简单打印            Header[] headers = getMethod.getResponseHeaders();            for(Header h : headers) {                System.out.println(h.getName() + "---------------" + h.getValue());            }            //读取HTTP响应内容，这里简单打印网页内容            //读取为字节数组            byte[] responseBody = getMethod.getResponseBody();            response = new String(responseBody, charset);            System.out.println("-----------response:" + response);            //读取为InputStream，在网页内容数据量大时候推荐使用            //InputStream response = getMethod.getResponseBodyAsStream();        } catch (HttpException e) {            //发生致命的异常，可能是协议不对或者返回的内容有问题            System.out.println("请检查输入的URL!");            e.printStackTrace();        } catch (IOException e) {            //发生网络异常            System.out.println("发生网络异常!");        } finally {            //6.释放连接            getMethod.releaseConnection();        }        return response;    }         public static String doPost(String url, JSONObject json){        HttpClient httpClient = new HttpClient();        PostMethod postMethod = new PostMethod(url);         postMethod.addRequestHeader("accept", "*/*");        postMethod.addRequestHeader("connection", "Keep-Alive");        //设置json格式传送        postMethod.addRequestHeader("Content-Type", "application/json;charset=GBK");        //必须设置下面这个Header        postMethod.addRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");        //添加请求参数        postMethod.addParameter("commentId", json.getString("commentId"));         String res = "";        try {            int code = httpClient.executeMethod(postMethod);            if (code == 200){                res = postMethod.getResponseBodyAsString();                System.out.println(res);            }        } catch (IOException e) {            e.printStackTrace();        }        return res;    }     public static void main(String[] args) {        System.out.println(doGet("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=telPhone", "GBK"));        System.out.println("-----------分割线------------");        System.out.println("-----------分割线------------");        System.out.println("-----------分割线------------");         JSONObject jsonObject = new JSONObject();        jsonObject.put("commentId", "telPhone");        System.out.println(doPost("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", jsonObject));    }}