一、概述
在实际开发过程中，我们经常需要调用对方提供的接口或测试自己写的接口是否合适。很多项目都会封装规定好本身项目的接口规范，所以大多数需要去调用对方提供的接口或第三方接口（短信、天气等）。
在 Java 项目中调用第三方接口的方式有：
- 通过 JDK 网络类 Java.net.HttpURLConnection ；
- 通过 common 封装好的 httpClient ；
- 通过 apache 封装好的 CloseableHttpClient ；
- 通过 SpringBoot-RestTemplate ；
二、 Java调用第三方http接口的方式
2.1、通过JDK网络类Java.net.HttpURLConnection
比较原始的一种调用做法，这里把get请求和post请求都统一放在一个方法里面。
实现过程：
GET:
- 创建远程连接
- 设置连接方式（get、post、put。。。）
- 设置连接超时时间
- 设置响应读取时间
- 发起请求
- 获取请求数据
- 关闭连接
POST:
- 创建远程连接
- 设置连接方式（get、post、put。。。）
- 设置连接超时时间
- 设置响应读取时间
- 当向远程服务器传送数据/写数据时，需要设置为true（setDoOutput）
- 当前向远程服务读取数据时，设置为true，该参数可有可无（setDoInput）
- 设置传入参数的格式:（setRequestProperty）
- 设置 鉴权 信息：Authorization:（setRequestProperty）
- 设置参数
- 发起请求
- 获取请求数据
- 关闭连接
直接上代码：
package com.riemann.springbootdemo.util.common.httpConnectionUtil;
import org.springframework.lang.Nullable;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURL Exception ;
import java.net.URL;
import java.net.URLConnection;
/**
* @author riemann
*/public class HttpURLConnectionUtil {
/**
* Http get请求
* @param httpUrl 连接
* @return 响应数据
*/ public static String Do Get(String httpUrl){
//链接
HttpURLConnection connection = null;
InputStream is = null;
BufferedReader br = null;
StringBuffer result = new StringBuffer();
try {
//创建连接
URL url = new URL(httpUrl);
connection = (HttpURLConnection) url.openConnection();
//设置请求方式
connection.setRequestMethod("GET");
//设置连接超时时间
connection.setReadTimeout();
//开始连接
connection.connect();
//获取响应数据
if (connection.getResponseCode() ==) {
//获取返回的数据
is = connection.getInputStream();
if (null != is) {
br = new BufferedReader(new InputStreamReader(is, " UTF-8 "));
String temp = null;
while (null != (temp = br.readLine())) {
result.append(temp);
}
}
}
} 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 result.toString();
}
/**
* Http post请求
* @param httpUrl 连接
* @param param 参数
* @return
*/ public static String doPost(String httpUrl, @Nullable String param) {
StringBuffer result = new StringBuffer();
//连接
HttpURLConnection connection = null;
OutputStream os = null;
InputStream is = null;
BufferedReader br = null;
try {
//创建连接对象
URL url = new URL(httpUrl);
//创建连接
connection = (HttpURLConnection) url.openConnection();
//设置请求方法
connection.setRequestMethod("POST");
//设置连接超时时间
connection.setConnectTimeout();
//设置读取超时时间
connection.setReadTimeout();
//DoOutput设置是否向httpUrlConnection输出，DoInput设置是否从httpUrlConnection读入，此外发送post请求必须设置这两个
//设置是否可读取
connection.setDoOutput(true);
connection.setDoInput(true);
//设置通用的请求属性
connection.set Request Property("accept", "*/*");
connection.setRequestProperty("connection", "Keep-Alive");
connection.setRequestProperty("user-agent", "Mozilla/.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
connection.setRequestProperty("Content-Type", "application/ JSON ; charset =utf-8");
//拼装参数
if (null != param && param.equals("")) {
//设置参数
os = connection.get Output Stream();
//拼装参数
os.write(param.get byte s("UTF-8"));
}
//设置权限
//设置请求头等
//开启连接
//connection.connect();
//读取响应
if (connection.getResponseCode() ==) {
is = connection.getInputStream();
if (null != is) {
br = new BufferedReader(new InputStreamReader(is, "GBK"));
String temp = null;
while (null != (temp = br.readLine())) {
result.append(temp);
result.append("rn");
}
}
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
//关闭连接
if(br!=null){
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (os!=null){
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(is!=null){
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
//关闭连接
connection.disconnect();
}
return result.toString();
}
public static void main(String[] args) {
String message = doPost("#34;, "");
System.out.println(message);
}
}
运行结果：
2.2 通过apache common封装好的HttpClient
httpClient的get或post请求方式步骤：
- 生成一个HttpClient对象并设置相应的参数；
- 生成一个GetMethod对象或PostMethod并设置响应的参数；
- 用HttpClient生成的对象来执行GetMethod生成的Get方法；
- 处理响应状态码；
- 若响应正常，处理HTTP响应内容；
- 释放连接。
导入如下jar包：
<!--HttpClient-->
<dependency>
<groupId>commons-httpclient</groupId>
<artifactId>commons-httpclient</artifactId>
<version>.1</version>
</dependency>
<!-- fastjson -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>.2.32</version>
</dependency>
代码如下：
package com.riemann.springbootdemo.util.common.httpConnectionUtil;
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;
/**
* @author riemann
*/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：
*.生成一个HttpClient对象并设置相应的参数；
*.生成一个GetMethod对象并设置响应的参数；
*.用HttpClient生成的对象来执行GetMethod生成的Get方法；
*.处理响应状态码；
*.若响应正常，处理HTTP响应内容；
*.释放连接。
* @param url
* @param charset
* @return
*/ public static String doGet(String url, String charset) {
//.生成HttpClient对象并设置参数
HttpClient httpClient = new HttpClient();
//设置Http连接超时为秒
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout();
//.生成GetMethod对象并设置参数
GetMethod getMethod = new GetMethod(url);
//设置get请求超时为秒
getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT,);
//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 = "";
//.执行HTTP GET 请求
try {
int statusCode = httpClient.executeMethod(getMethod);
//.判断访问的状态码
if (statusCode != HttpStatus.SC_OK) {
System.err.println("请求出错：" + getMethod.getStatusLine());
}
//.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 {
//.释放连接
getMethod.releaseConnection();
}
return response;
}
/**
* post请求
* @param url
* @param json
* @return
*/ public static String doPost(String url, json Object 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/.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 ==){
res = postMethod.getResponseBodyAsString();
System.out.println(res);
}
} catch (IOException e) {
e.printStackTrace();
}
return res;
}
public static void main(String[] args) {
System.out.println(doGet("#;, "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", "");
System.out.println(doPost("#;, jsonObject));
}
}
运行结果：
post请求的 jsonObject 的参数也成功写入
2.3 通过Apache封装好的CloseableHttpClient
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，当然上面两种方式也是可以设置请求头token、json的，这里只在下面说明。
导入如下jar包：
<!--CloseableHttpClient-->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>.5.2</version>
</dependency>
<!--fastjson-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>.2.32</version>
</dependency>
代码如下：
package com.riemann.springbootdemo.util.common.httpConnectionUtil;
import com.alibaba.fastjson.JSONObject;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.CloseableHttpResponse;
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;
/**
* @author riemann
*/public class CloseableHttpClientUtil {
private static String tokenString = "";
private static String AUTH_TOKEN_EXPIRED = "AUTH_TOKEN_EXPIRED";
private static CloseableHttpClient httpClient = null;
/**
* 以get方式调用第三方接口
* @param url
* @param token
* @return
*/ public static String doGet(String url, String token) {
//创建HttpClient对象
CloseableHttpClient httpClient = HttpClientBuilder.create().build();
HttpGet httpGet = new HttpGet(url);
if (null != tokenString && !tokenString.equals("")) {
tokenString = getToken();
}
//api_gateway_auth_token自定义header头，用于token验证使用
httpGet.addHeader("api_gateway_auth_token",tokenString);
httpGet.addHeader("User-Agent", "Mozilla/.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);
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
//返回json格式
String res = EntityUtils.toString(response.getEntity());
return res;
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
/**
* 以post方式调用第三方接口
* @param url
* @param json
* @return
*/ public static String doPost(String url, JSONObject json) {
if (null == httpClient) {
httpClient = HttpClientBuilder.create().build();
}
HttpPost httpPost = new HttpPost(url);
if (null != tokenString && tokenString.equals("")) {
tokenString = getToken();
}
//api_gateway_auth_token自定义header头，用于token验证使用
httpPost.addHeader("api_gateway_auth_token", tokenString);
httpPost.addHeader("User-Agent", "Mozilla/.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(json.toString());
se.setContentEncoding("UTF-");
//发送json数据需要设置contentType
se.setContentType("application/x-www-form-urlencoded");
//设置请求参数
httpPost.setEntity(se);
HttpResponse response = httpClient.execute(httpPost);
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
//返回json格式
String res = EntityUtils.toString(response.getEntity());
return res;
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (httpClient != null){
try {
httpClient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return null;
}
/**
* 获取第三方接口的token
*/ public 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("#;");
httpPost.addHeader("User-Agent", "Mozilla/.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());
se.setContentEncoding("UTF-");
//发送json数据需要设置contentType
se.setContentType("application/x-www-form-urlencoded");
//设置请求参数
httpPost.setEntity(se);
HttpResponse response = httpClient.execute(httpPost);
//这里可以把返回的结果按照自定义的返回数据结果，把string转换成自定义类
//ResultTokenBO result = JSONObject.parseObject(response, ResultTokenBO.class);
//把response转为jsonObject
JSONObject result = (JSONObject) JSONObject.parseObject(String.valueOf(response));
if (result.containsKey("token")) {
token = result.getString("token");
}
} catch (IOException e) {
e.printStackTrace();
}
return token;
}
/**
* 测试
*/ public static void test(String telephone) {
JSONObject object = new JSONObject();
object.put("telephone", telephone);
//首先获取token
tokenString = getToken();
String response = doPost("#;, object);
//如果返回的结果是list形式的，需要使用JSONObject.parseArray转换
//List<Result> list = JSONObject.parseArray(response, Result.class);
System.out.println(response);
}
public static void main(String[] args) {
test("");
}
}
2.4 通过SpringBoot-RestTemplate
springBoot-RestTemple 是上面三种方式的集大成者，代码编写更加简单，目前可以采用的调用第三方接口有：
- delete() 在特定的URL上对资源执行 HTTP DELETE 操作
- exchange() 在URL上执行特定的HTTP方法，返回包含对象的 ResponseEntity ，这个对象是从响应体中映射得到的
- execute() 在URL上执行特定的HTTP方法，返回一个从响应体映射得到的对象
- getForEntity() 发送一个 HTTP GET 请求，返回的 ResponseEntity 包含了响应体所映射成的对象
- getForObject() 发送一个 HTTP GET 请求，返回的请求体将映射为一个对象
- postForEntity() POST 数据到一个URL，返回包含一个对象的 ResponseEntity ，这个对象是从响应体中映射得到的
- postForObject() POST 数据到一个URL，返回根据响应体匹配形成的对象
- headForHeaders() 发送 HTTP HEAD 请求，返回包含特定资源URL的HTTP头
- optionsForAllow() 发送 HTTP OPTIONS 请求，返回对特定URL的Allow头信息
- postForLocation() POST 数据到一个URL，返回新创建资源的URL
- put() PUT 资源到特定的URL
首先导入springboot的web包
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>.0.4.RELEASE</version>
</parent>
<dependencies>
<!--CloseableHttpClient-->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>.5.2</version>
</dependency>
<!--spring restTemplate-->
<!-- @ConfigurationProperties annotation processing (metadata for IDEs)
生成spring-configuration-metadata.json类，需要引入此类-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
在启动类同包下创建 RestTemplateConfig.java 类
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;
/**
* @author riemann
*/@Configuration
public class RestTemplateConfig {
@Bean
public RestTemplate restTemplate(ClientHttpRequestFactory factory){
return new RestTemplate(factory);
}
@Bean
public ClientHttpRequestFactory simpleClientHttpRequestFactory(){
SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
factory.setConnectTimeout();
factory.setReadTimeout();
return factory;
}
}
然后在Service类（ RestTemplateToInterface ）中注入使用
具体代码如下：
import com.alibaba.fastjson.JSONObject;
import com.swordfall.model.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.*;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
/**
* @author riemann
*/@Service
public class RestTemplateToInterface {
@Autowired
private RestTemplate restTemplate;
/**
* 以get方式请求第三方http接口 getForEntity
* @param url
* @return
*/ public User doGetWith(String url){
ResponseEntity<User> responseEntity = restTemplate.getForEntity(url, User.class);
User user = responseEntity.getBody();
return user;
}
/**
* 以get方式请求第三方http接口 getForObject
* 返回值返回的是响应体，省去了我们再去getBody()
* @param url
* @return
*/ public User doGetWith(String url){
User user = restTemplate.getForObject(url, User.class);
return user;
}
/**
* 以post方式请求第三方http接口 postForEntity
* @param url
* @return
*/ public String doPostWith(String url){
User user = new User("小白",);
ResponseEntity<String> responseEntity = restTemplate.postForEntity(url, user, String.class);
String body = responseEntity.getBody();
return body;
}
/**
* 以post方式请求第三方http接口 postForEntity
* @param url
* @return
*/ public String doPostWith(String url){
User user = new User("小白",);
String body = restTemplate.postForObject(url, user, String.class);
return body;
}
/**
* exchange
* @return
*/ public String doExchange(String url, Integer age, String name){
//header参数
HttpHeaders headers = new HttpHeaders();
String token = "asdfaf";
headers.add("authorization", token);
headers.setContentType(MediaType.APPLICATION_JSON);
//放入body中的json参数
JSONObject obj = new JSONObject();
obj.put("age", age);
obj.put("name", name);
//组装
HttpEntity<JSONObject> request = new HttpEntity<>(obj, headers);
ResponseEntity<String> responseEntity = restTemplate.exchange(url, HttpMethod.POST, request, String.class);
String body = responseEntity.getBody();
return body;
}
}
2.5 通过okhttp
应大家的响应，okhttp 现在也是蛮流行的，基于手机端很火，这里分享一下 OkHttpClient 客户端，业务代码get、post请求直接调用就好哈。
pom文件引入依赖包
<dependency>
<groupId>com.squareup.okhttp</groupId>
<artifactId>okhttp</artifactId>
<version>.10.0</version>
</dependency>
@Slfj
public class OkHttpClient {
private static final MediaType JSON = MediaType.parse("application/json; charset=utf-");
private volatile static okhttp.OkHttpClient client;
private static final int MAX_IDLE_CONNECTION = Integer
.parseInt(ConfigManager.get("httpclient.max_idle_connection"));
private static final long KEEP_ALIVE_DURATION = Long
.parseLong(ConfigManager.get("httpclient.keep_alive_duration"));
private static final long CONNECT_TIMEOUT = Long.parseLong(ConfigManager.get("httpclient.connectTimeout"));
private static final long READ_TIMEOUT = Long.parseLong(ConfigManager.get("httpclient. "));
/**
* 单例模式(双重检查模式) 获取类实例
*
* @return client
*/ private static okhttp.OkHttpClient getInstance() {
if (client == null) {
synchronized (okhttp.OkHttpClient.class) {
if (client == null) {
client = new okhttp.OkHttpClient.Builder()
.connectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS)
.readTimeout(READ_TIMEOUT, TimeUnit.SECONDS)
.connectionPool(new ConnectionPool(MAX_IDLE_CONNECTION, KEEP_ALIVE_DURATION,
TimeUnit.MINUTES))
.build();
}
}
}
return client;
}
public static String syncPost(String url, String json) throws IOException {
RequestBody body = RequestBody.create(JSON, json);
Request request = new Request.Builder()
.url(url)
.post(body)
.build();
try {
Response response = OkHttpClient.getInstance().newCall(request).execute();
if (response.isSuccessful()) {
String result = response.body().string();
log.info("syncPost response = {}, responseBody= {}", response, result);
return result;
}
String result = response.body().string();
log.info("syncPost response = {}, responseBody= {}", response, result);
throw new IOException("三方接口返回http状态码为" + response.code());
} catch (Exception e) {
log.error("syncPost() url:{} have a ecxeption {}", url, e);
throw new RuntimeException("syncPost() have a ecxeption {}" + e.getMessage());
}
}
public static String syncGet(String url, Map<String, Object> headParamsMap) throws IOException {
Request request;
final Request.Builder builder = new Request.Builder().url(url);
try {
if (!CollectionUtils.isEmpty(headParamsMap)) {
final Iterator<Map.Entry<String, Object>> iterator = headParamsMap.entrySet()
.iterator();
while (iterator.hasNext()) {
final Map.Entry<String, Object> entry = iterator.next();
builder.addHeader(entry.getKey(), (String) entry.getValue());
}
}
request = builder.build();
Response response = OkHttpClient.getInstance().newCall(request).execute();
String result = response.body().string();
log.info("syncGet response = {},responseBody= {}", response, result);
if (!response.isSuccessful()) {
throw new IOException("三方接口返回http状态码为" + response.code());
}
return result;
} catch (Exception e) {
log.error("remote interface url:{} have a ecxeption {}", url, e);
throw new RuntimeException("三方接口返回异常");
}
}
}