java中调用第三方接口很常见，本文使用的是CloseableHttpClient方式。
CloseableHttpClient是在HttpClient的基础上修改更新而来的，这里还涉及到请求头token的设置（请求验证），利用fastjson转换请求或返回结果字符串为json格式。
- 导入jar包
<properties> <httpclient.version>4.5.5</httpclient.version> <slf4j.version>1.7.25</slf4j.version> <fastjson.version>1.2.47</fastjson.version> </properties>
<dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>${httpclient.version}</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>${slf4j.version}</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>${fastjson.version}</version> </dependency>
- httpclient公共类：
package com.howdy.callapi.common; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.JSONObject; import com.sun.istack.internal.logging.Logger; import org.apache.http.HttpResponse; import org.apache.http.HttpStatus; import org.apache.http.client.HttpClient; import org.apache.http.client.config.RequestConfig; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.config.ConnectionConfig; import org.apache.http.config.SocketConfig; import org.apache.http.entity.StringEntity; 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; import org.apache.http.util.EntityUtils; import org.springframework.stereotype.Service; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.net.URI; import java.nio.charset.Charset; import java.util.Map; @Service public class HttpUtil { private static Logger logger = Logger.getLogger(HttpUtil.class); private static CloseableHttpClient httpClient = null; private static final Charset CHAR_SET = Charset.forName("utf-8"); private static PoolingHttpClientConnectionManager cm; public HttpUtil(){ init(); } public void init() { cm = new PoolingHttpClientConnectionManager(); //设置最大连接数 cm.setMaxTotal(300); //设置每个主机地址的并发数 // cm.setDefaultMaxPerRoute(100); cm.setDefaultConnectionConfig(ConnectionConfig.custom() .setCharset(CHAR_SET).build()); SocketConfig socketConfig = SocketConfig.custom().setSoTimeout(30000) .setSoReuseAddress(true).build(); cm.setDefaultSocketConfig(socketConfig); httpClient = HttpClientBuilder.create().setConnectionManager(cm) .build(); } public CloseableHttpClient getHttpClient() { int timeout=5; RequestConfig config = RequestConfig.custom() .setConnectTimeout(timeout * 1000) //设置连接超时时间，单位毫秒 //.setConnectionRequestTimeout(timeout * 1000) //设置从connect Manager获取Connection 超时时间，单位毫秒 .setSocketTimeout(timeout * 1000).build(); //请求获取数据的超时时间，单位毫秒 CloseableHttpClient _httpClient = HttpClients.custom() .setConnectionManager(cm) // .setDefaultRequestConfig(config) //使用此方法连接池会关闭 .setConnectionManagerShared(true) .build(); if(cm!=null&&cm.getTotalStats()!=null) { //打印连接池的状态 logger.info("now client pool {}"+cm.getTotalStats().toString()); } return _httpClient; } /** * get请求 * * @return */ public String doGet(String url) { try { HttpClient client = getHttpClient(); //发送get请求 HttpGet request = new HttpGet(url); HttpResponse response = client.execute(request); /**请求发送成功，并得到响应**/ if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { /**读取服务器返回过来的json字符串数据**/ String strResult = EntityUtils.toString(response.getEntity()); request.releaseConnection(); return strResult; } } catch (IOException e) { e.printStackTrace(); } return null; } /** * post请求 参数为map格式 * * @param url * @param params * @return */ public String doPost(String url, Map params) { BufferedReader in = null; try { // 定义HttpClient CloseableHttpClient client =getHttpClient(); // 实例化HTTP方法 HttpPost request = new HttpPost(); request.setURI(new URI(url)); request.setHeader("Content-Type","application/json; charset=utf-8"); StringEntity s = new StringEntity(JSON.toJSONString(params)); request.setEntity(s); HttpResponse response = client.execute(request); int code = response.getStatusLine().getStatusCode(); if (code == 200) { //返回json格式 String res = EntityUtils.toString(response.getEntity()); request.releaseConnection(); return res; } else { // System.out.println("状态码：" + code); return null; } } catch (Exception e) { e.printStackTrace(); return null; } } /** * 以post方式 请求参数为json格式 * @param url * @param json * @return */ public String doPost(String url, JSONObject json){ HttpPost post = new HttpPost(url); try { if (httpClient == null){ // httpClient = HttpClientBuilder.create().build(); httpClient= HttpClients.custom().setConnectionManager(cm).setConnectionManagerShared(true).build(); } httpClient=getHttpClient(); //api_gateway_auth_token自定义header头，用于token验证使用 // post.addHeader("api_gateway_auth_token", tokenString); post.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"); post.setHeader("Content-type", "application/json;charset=utf-8"); post.setHeader("Connection", "Close"); StringEntity s = new StringEntity(json.toString()); s.setContentEncoding("UTF-8"); //发送json数据需要设置contentType s.setContentType("application/x-www-form-urlencoded"); //设置请求参数 post.setEntity(s); HttpResponse response = httpClient.execute(post); if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK){ //返回json格式 String res = EntityUtils.toString(response.getEntity()); post.releaseConnection(); return res; } } catch (Exception e) { logger.info("excep:"+e.getMessage()); e.printStackTrace(); }finally { if (post != null) post.releaseConnection(); if (httpClient != null){ try { httpClient.close(); } catch (IOException e) { e.printStackTrace(); } } } return null; } }
- controller调用：
package com.howdy.callapi.controller; import com.alibaba.fastjson.JSONObject; import com.howdy.callapi.common.HttpUtil; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import java.util.HashMap; import java.util.Map; @RestController @RequestMapping("/callapi") public class CallController { @Autowired private HttpUtil httpUtil; @GetMapping("/getdetail") public String getdetail(){ String result= httpUtil.doGet("https://***/ById?id=3"); System.out.println(result); return result; } @PostMapping("/getlist") public String getlist(){ HttpUtil util=new HttpUtil(); JSONObject jsonObject=new JSONObject(); jsonObject.put("pageIndex",1); jsonObject.put("pageCount",10); jsonObject.put("start_time",""); jsonObject.put("end_time",""); String result= httpUtil.doPost("https://***/GetMen",jsonObject); System.out.println("jsonobject:"+result); return result; } @PostMapping("/getlist2") public String getlist2(){ Map params=new HashMap<>(); params.put("pageIndex",1); params.put("pageCount",10); params.put("start_time",""); params.put("end_time",""); String result2= httpUtil.doPost(https://***/GetMen",params); System.out.println("jsonobject2:"+result2); return result2; } }