本文主要以代码的形式讲解如下四种http客户端连接方式的基础使用
- 通过JDK网络类HttpURLConnection
- 通过common封装好的httpclient
- 通过Apache封装好的CloseableHttpClient
- 通过OkHttpClient
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1、首先定义http请求中常用的请求方式
package com.liziba.http.utils;import java.util.Arrays;import java.util.HashMap;import java.util.Map;/** * @auther LiZiBa * @date 2020/12/11 23:44 * @description: Http方式 **/public enum HttpMethod { GET, POST, PUT, DELETE, HEAD, OPTIONS, PATCH, TRACE; private static final Map mappings; public boolean matches(String method) { return this == resolve(method); } public static HttpMethod resolve(String method) { return ((method != null) ? (HttpMethod)mappings.get(method) : null); } static { mappings = new HashMap<>(8); HttpMethod[] arrayOfHttpMethod = values(); Arrays.asList(arrayOfHttpMethod).forEach(m -> { mappings.put(m.name(), m); }); }}2、通过JDK网络类HttpURLConnection
package com.liziba.http.utils;import com.sun.istack.internal.Nullable;import java.io.*;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;/** * @auther LiZiBa * @date 2020/12/11 23:40 * @description: 通过JDK网络类java.net.HttpURLConnection类实现调用第三方Http接口 **/public class HttpURLConnectionUtil { /** * HTTP GET请求 * @param httpUrl 请求连接地址 * @return 返回请求结果 */ public static String doGet(String httpUrl) { HttpURLConnection connection = null; InputStream is = null; BufferedReader br = null; StringBuffer sb = new StringBuffer(); try { URL url = new URL(httpUrl); connection = (HttpURLConnection) url.openConnection(); // 设置请求方式 connection.setRequestMethod(HttpMethod.GET.name()); // 设置超时时间 毫秒 connection.setConnectTimeout(60000); // 开始连接 connection.connect(); // 相应结果为200则获取相应数据 if(connection.getResponseCode() == 200) { is = connection.getInputStream(); if(null != br) { // 缓冲字符流读取数据 br = new BufferedReader(new InputStreamReader(is, "UTF-8")); String line = null; while(null != (line = br.readLine()) ) { sb.append(line); } } } }catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }finally { if (null != br) { try { br.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != is) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } // 关闭远程连接 connection.disconnect(); } return sb.toString(); } /** * HTTP POST请求 * @param httpUrl 请求连接地址 * @param param 请求参数 * @return 接口返回结果 */ public static String doPost(String httpUrl, @Nullable String param) { HttpURLConnection connection = null; InputStream is = null; OutputStream os = null; BufferedReader br = null; StringBuffer sb = new StringBuffer(); try { URL url = new URL(httpUrl); // 建立连接 connection = (HttpURLConnection) url.openConnection(); // 设置请求方式 connection.setRequestMethod(HttpMethod.POST.name()); // 设置请求连接超时时间 connection.setConnectTimeout(60000); // 设置读取超时时间 connection.setReadTimeout(15000); // setDoInput设置是否可以从HttpURLConnection读取数据 connection.setDoInput(true); // setDoOutput设置是否可以从HttpURLConnection输出数据 connection.setDoOutput(true); // 设置通用请求属性 connection.setRequestProperty("accept", "/"); connection.setRequestProperty("connection", "Keep-Alive"); connection.setRequestProperty("user-agent", "Mozilla/4.0(compatible; MSIE 6.0; Windows NT 5.1; SV1)"); connection.setRequestProperty("Content-Type", "application/json;charset=utf-8"); // 设置请求参数 if(null != param && !"".equals(param)) { os = connection.getOutputStream(); os.write(param.getBytes("UTF-8")); } // 开启连接 connection.connect(); // 读取数据 if(connection.getResponseCode() == 200) { is = connection.getInputStream(); if(null != is) { br = new BufferedReader(new InputStreamReader(is, "GBK"));// UTF-8 String readLine = null; while(null != (readLine = br.readLine())) { sb.append(readLine); sb.append("\r\n"); } } } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }finally { // 关闭连接流 if (null != br) { try { br.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != is) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != os) { try { os.close(); } catch (IOException e) { e.printStackTrace(); } } // 关闭连接 connection.disconnect(); } return sb.toString(); }}3、通过common封装好的httpclient
package com.liziba.http.utils;import com.alibaba.fastjson.JSONObject;import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;import org.apache.commons.httpclient.Header;import org.apache.commons.httpclient.HttpClient;import org.apache.commons.httpclient.HttpStatus;import org.apache.commons.httpclient.methods.GetMethod;import org.apache.commons.httpclient.methods.PostMethod;import org.apache.commons.httpclient.params.HttpMethodParams;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.util.Arrays;/** * @auther LiZiBa * @date 2020/12/12 9:15 * @description: **/public class HttpClientUtil { public static String doGet(String httpUrl, String charset) { // 1、创建HttpClient对象 HttpClient httpClient = new HttpClient(); // 设置连接超时时间为6秒 httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(6000); // 2、创建GetMethod对象并设置参数 GetMethod getMethod = new GetMethod(httpUrl); // 设置http get请求超时时间为6秒 getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 6000); // 设置默认请求重试次数，DefaultHttpMethodRetryHandler默认为3次 getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler()); BufferedReader bufferedReader = null; StringBuffer response = new StringBuffer(); // 3、执行请求 try { // 4、判断请求返回状态码 int statusCode = httpClient.executeMethod(getMethod); // 请求错误简单输出错误 if(statusCode != HttpStatus.SC_OK) { System.err.println(String.format("请求错误：%s", getMethod.getStatusLine())); } // 5、处理请求响应内容 // http 响应头打印 Header[] responseHeaders = getMethod.getResponseHeaders(); Arrays.asList(responseHeaders).forEach(h -> { System.out.println(h.getName() + "-" + h.getValue()); }); // http 响应体内容 InputStream is = getMethod.getResponseBodyAsStream(); bufferedReader = new BufferedReader(new InputStreamReader(is, charset)); String readLine = null; while(null != (readLine = bufferedReader.readLine())) { response.append(readLine); response.append("\r\n"); } System.out.println("请求内容 response："+ response.toString()); } catch (IOException e) { e.printStackTrace(); } finally { // 释放连接 getMethod.releaseConnection(); } return response.toString(); } /** * HttpClient 请求 * @param httpUrl * @param charset * @return */ public static String doPost(String httpUrl, String charset, JSONObject json) { HttpClient httpClient = new HttpClient(); // http post 请求 PostMethod postMethod = new PostMethod(httpUrl); // 设置请求头通用参数 postMethod.addRequestHeader("accept", "/"); postMethod.addRequestHeader("connection", "Keep-Alive"); postMethod.addRequestHeader("Content-Type", "application/json;charset=" + charset); 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"); // 演示添加 请求参数 postMethod.addParameter("param", json.getString("param")); BufferedReader bufferedReader = null; StringBuffer response = new StringBuffer(); try { int statusCode = httpClient.executeMethod(postMethod); // 只处理正确内容，其余可自行补充 if(statusCode == HttpStatus.SC_OK) { // http 响应体内容 InputStream is = postMethod.getResponseBodyAsStream(); bufferedReader = new BufferedReader(new InputStreamReader(is, charset)); String readLine = null; while(null != (readLine = bufferedReader.readLine())) { response.append(readLine); response.append("\r\n"); } System.out.println("响应内容 response:" + response.toString()); } } catch (IOException e) { e.printStackTrace(); } finally { // 释放连接 postMethod.releaseConnection(); } return response.toString(); }}4、通过Apache封装好的CloseableHttpClient
package com.liziba.http.util;import com.alibaba.fastjson.JSONObject;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.HttpStatus;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.entity.StringEntity;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClientBuilder;import org.apache.http.util.EntityUtils;import java.io.IOException;import java.io.UnsupportedEncodingException;/** * @auther LiZiBa * @date 2020/12/12 10:44 * @description: **/public class CloseableHttpClientUtil { private static CloseableHttpClient httpClient = null; /** * get 请求接口 * @param url 请求地址 * @param token 请求token * @return */ public static String doGet(String url, String token) { httpClient = HttpClientBuilder.create().build(); HttpGet httpGet = new HttpGet(url); if (null != token && !"".equals(token)) { token = getToken(); } // 后端接口或者网关层自定义token验证key httpGet.addHeader("gateway_auth_token", token); httpGet.addHeader("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"); try { HttpResponse response = httpClient.execute(httpGet); // 连接正常返回 if(response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { HttpEntity entity = response.getEntity(); String result = EntityUtils.toString(entity); return result; } } catch (IOException e) { e.printStackTrace(); } finally { if (null != httpClient) { try { httpClient.close(); } catch (IOException e) { e.printStackTrace(); } } } return null; } /** * post 请求接口 * @param url 请求地址 * @param token 请求token * @param param 请求参数 * @return */ private static String doPost(String url, String token, JSONObject param) { httpClient = HttpClientBuilder.create().build(); HttpPost httpPost = new HttpPost(url); if (null != token && !"".equals(token)) { token = getToken(); } // 后端接口或者网关层自定义token验证key httpPost.addHeader("gateway_auth_token", token); httpPost.addHeader("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"); try { StringEntity se = new StringEntity(param.toString()); se.setContentEncoding("UTF-8"); // 设置ContentType以便于传输JSON数据 se.setContentType("application/x-www-form-urlencoded"); // 设置请求参数 httpPost.setEntity(se); // 执行请求 HttpResponse response = httpClient.execute(httpPost); if(response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { HttpEntity entity = response.getEntity(); String result = EntityUtils.toString(entity); return result; } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if(null != httpClient) { try { httpClient.close(); } catch (IOException e) { e.printStackTrace(); } } } return null; } /** * 指定地址获取token * @return */ private static String getToken() { String token = ""; JSONObject object = new JSONObject(); object.put("appId", "appId"); object.put("secretKey", "secretKey"); if (null == httpClient) { httpClient = HttpClientBuilder.create().build(); } HttpPost httpPost = new HttpPost("http://localhost:8080/oig/getToken"); httpPost.addHeader("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"); try { StringEntity se = new StringEntity(object.toString()); // 设置编码格式 se.setContentEncoding("UTF-8"); // 设置ContentType以便于传输JSON数据 se.setContentType("application/x-www-form-urlencoded"); // 设置请求参数 httpPost.setEntity(se); // 执行请求 HttpResponse response = httpClient.execute(httpPost); // 根据接口规范解析自定义返回结果 JSONObject result = JSONObject.parseObject(String.valueOf(response)); // 判断是否包含token if(result.containsKey("token")) { token = result.getString("token"); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return token; }}5、通过OkHttpClient
package com.liziba.http.util;import okhttp3.*;import java.io.*;import java.util.concurrent.TimeUnit;/** * @auther LiZiBa * @date 2020/12/12 12:30 * @description: **/public class OkHttpUtil { /** * 同步get方式请求 * @param url 请求接口地址 * @return */ public static void syncGet(String url) { // 1、创建一个OkHttpClient对象 OkHttpClient client = new OkHttpClient(); // 2、创建一个请求 Request request = new Request.Builder().url(url).build(); InputStream is = null; BufferedReader br = null; StringBuffer result = null; try { // 3、返回实体 Response response = client.newCall(request).execute(); if (response.isSuccessful()){ // 小数据量 1M以下// temp = response.body().string(); // 返回数据较大 is = response.body().byteStream(); if(null != is) { String temp = null; br = new BufferedReader(new InputStreamReader(is, "UTF-8")); while (null != (temp = br.readLine())) { result.append(temp); result.append("/r/n"); } } } else { System.err.println("请求错误！"); } } catch (IOException e) { e.printStackTrace(); } finally { if(null != br) { try { br.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != is) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } } } /** * get 异步请求 * @param url 请求地址 */ public static void asyncGet(String url) { OkHttpClient client = new OkHttpClient(); Request request = new Request.Builder().url(url).build(); client.newCall(request).enqueue(new Callback() { // 请求失败回调 public void onFailure(Call call, IOException e) { System.err.println(e.getMessage()); } // 请求成功回调 public void onResponse(Call call, Response response) throws IOException { InputStream is = null; BufferedReader br = null; StringBuffer result = null; try{ is = response.body().byteStream(); if(null != is) { String temp = null; br = new BufferedReader(new InputStreamReader(is, "UTF-8")); while (null != (temp = br.readLine())) { result.append(temp); result.append("/r/n"); } } }catch (Exception e) { e.printStackTrace(); }finally { if(null != br) { try { br.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != is) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } } } }); } /** * post 提交表单 * @param url 请求参数 * @param param 请求地址 */ public static void postFormParameters(String url, String param) { // 创建OkHttpClient OkHttpClient client = new OkHttpClient(); // 表单键值对 FormBody formBody = new FormBody.Builder().add("key", param).build(); // 发起请求 Request request = new Request.Builder().url(url).post(formBody).build(); // 异步回调 client.newCall(request).enqueue(new Callback() { // 错误回调 public void onFailure(Call call, IOException e) { System.err.println("错误回调..."); } // 成功回调 public void onResponse(Call call, Response response) throws IOException { System.out.println("成功回调..."); } }); } /** * post 提交字符串 * @param url */ public static void postStringParameters(String url) { MediaType mediaType = MediaType.parse("text/text;charset=utf-8"); // 创建OkHttpClient OkHttpClient client = new OkHttpClient(); // 需要提交的字符串 String key = "liziba"; Request request = new Request.Builder().url(url).post(RequestBody.create(mediaType, key)).build(); client.newCall(request).enqueue(new Callback() { // 错误回调 public void onFailure(Call call, IOException e) { System.err.println("错误回调..."); } // 成功回调 public void onResponse(Call call, Response response) throws IOException { System.out.println("成功回调..."); } }); } /** * 设置超时时间 */ public static OkHttpClient timeOutClient() { OkHttpClient client = new OkHttpClient.Builder() .connectTimeout(10, TimeUnit.SECONDS) // 设置连接超时时间 .readTimeout(10, TimeUnit.SECONDS) // 设置读数据超时时间 .writeTimeout(10, TimeUnit.SECONDS) // 设置写数据超时时间 .build(); return client; } /** * 缓存设置 */ public static void cacheClient() throws Exception{ // 缓存路径 File f = new File("d:/file_cache"); // 设置缓存大小 100MB int cacheSize = 100 * 1024 * 1024; // 构建一个缓存OkHttpClient连接 OkHttpClient client =new OkHttpClient.Builder() .cache(new Cache(f.getAbsoluteFile(), cacheSize)) .build(); }}本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。
