java远程调用接口、URL的方式

一:httpUrlConnection

1.获取HttpURLConnection连接对象

   /**
     * 获取HttpURLConnection连接对象
     * @param url 远程调用的url
     * @return
     */
    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

/**
     * 远程调用登录接口
     */
    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

  • 1.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。

  • 2.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。

  • 3.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。

  • 4.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

@Configuration
public 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

/**
     * 远程调用登录接口
     */
    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;
 
/**
 * ************************************************************
 * Copyright © 2020 cnzz Inc.All rights reserved.  *    **
 * ************************************************************
 *
 * @program: demo
 * @description:
 * @author: cnzz
 * @create: 2020-12-23 17:41
 **/
 
public class HttpClientUtil {
 
    /**
     * httpClient的get请求方式
     * 使用GetMethod来访问一个URL对应的网页实现步骤:
     * 1.生成一个HttpClient对象并设置相应的参数;
     * 2.生成一个GetMethod对象并设置响应的参数;
     * 3.用HttpClient生成的对象来执行GetMethod生成的Get方法;
     * 4.处理响应状态码;
     * 5.若响应正常,处理HTTP响应内容;
     * 6.释放连接。
     * @param url
     * @param charset
     * @return
     */
    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;
    }
 
    /**
     * post请求
     * @param url
     * @param json
     * @return
     */
    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));
    }
}

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