用java调用第三方接口

用java调用第三方接口，传递form-data或者x-www-form-urlencoded类型的参数

这是需要引入的包

import org.apache.commons.text.StringEscapeUtils;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

这里需要提供第三方接口的URL，以及map类型的参数

 public static String doPost(String url, Map<String, String> param) {
        // 创建Httpclient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();
        CloseableHttpResponse response = null;
        String resultString = "";
        try {
            // 创建Http Post请求
            HttpPost httpPost = new HttpPost(url);
            // 创建参数列表
            if (param != null) {
                List<NameValuePair> paramList = new ArrayList<>();
                for (String key : param.keySet()) {
                    paramList.add(new BasicNameValuePair(key, param.get(key)));
                }
                // 模拟表单
                UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList);
                httpPost.setEntity(entity);
            }
            // 执行http请求
            response = httpClient.execute(httpPost);
            resultString = EntityUtils.toString(response.getEntity(), "utf-8");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return resultString;
    }

返回结果是String类型

第二种：

需要引入的包

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

代码（方法）

 /**
     * 以post或get方式调用对方接口方法
     */
    public static void doPostOrGet(String pathUrl, String data) {
        OutputStreamWriter out = null;
        BufferedReader br = null;
        String result = "";
        try {
            URL url = new URL(pathUrl);
            //打开和url之间的连接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            //请求方式
            conn.setRequestMethod("POST");
            //conn.setRequestMethod("GET");

            //设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
            conn.setRequestProperty("Content-Type", "application/json;charset=utf-8");

            //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
            conn.setDoOutput(true);
            conn.setDoInput(true);

            /**
             * 下面的三句代码，就是调用第三方http接口
             */
            //获取URLConnection对象对应的输出流
            out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            //发送请求参数即数据
            out.write(data);
            //flush输出流的缓冲
            out.flush();

            /**
             * 下面的代码相当于，获取调用第三方http接口后返回的结果
             */
            //获取URLConnection对象对应的输入流
            InputStream is = conn.getInputStream();
            //构造一个字符流缓存
            br = new BufferedReader(new InputStreamReader(is));
            String str = "";
            while ((str = br.readLine()) != null) {
                result += str;
            }
            System.out.println(result);
            //关闭流
            is.close();
            //断开连接，disconnect是在底层tcp socket链接空闲时才切断，如果正在被其他线程使用就不切断。
            conn.disconnect();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (br != null) {
                    br.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

第三种：

引入的包

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

代码方法：

public static void interfaceDemo(String path, String data) {
        try {
            URL url = new URL(path);
            //打开和url之间的连接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            PrintWriter out = null;
            //请求方式
            //conn.setRequestMethod("POST");
            //设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
            conn.setDoOutput(true);
            conn.setDoInput(true);
            //获取URLConnection对象对应的输出流
            out = new PrintWriter(conn.getOutputStream());
            //发送请求参数即数据
            out.print(data);
            //缓冲数据
            out.flush();
            //获取URLConnection对象对应的输入流
            InputStream is = conn.getInputStream();
            //构造一个字符流缓存
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            String str = "";
            while ((str = br.readLine()) != null) {
                System.out.println(str);
            }
            //关闭流
            is.close();
            //断开连接，最好写上，disconnect是在底层tcp socket链接空闲时才切断。如果正在被其他线程使用就不切断。
            //固定多线程的话，如果不disconnect，链接会增多，直到收发不出信息。写上disconnect后正常一些。
            conn.disconnect();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

第四种：

需要引入的包

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

代码

public static String getHtmlByPost(String urlString) throws IOException {
        URL url = new URL(urlString);
        //参数
        StringBuilder parameterbulider = new StringBuilder();
        //响应
        StringBuilder responseBuilder = new StringBuilder();
        BufferedReader reader = null;
        PrintWriter out = null;
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setInstanceFollowRedirects(false);
        //post 请求必须设置此处
        conn.setDoOutput(true);
        conn.setDoInput(true);
        conn.setUseCaches(false);
        conn.setDefaultUseCaches(false);
        //连接超时
        conn.setConnectTimeout(30 * 1000);
        //读取超时
        conn.setReadTimeout(30 * 1000);
        conn.setRequestMethod("POST");
        //多个参数拼接
        parameterbulider.append("sign=3149fa619b03988963bf1c53b8947f0e");
        parameterbulider.append("Content-Type=application/x-www-form-urlencoded");
        parameterbulider.append("Content-Length=285");
        parameterbulider.append("Host=www.xxx.com");
        parameterbulider.append("Connection=Keep-Alive");
        parameterbulider.append("Accept-Encoding=gzip");
        parameterbulider.append("User-Agent=okhttp/3.2.0");
        parameterbulider.append("_time=2017-12-15%2011%3A07%3A02&user_coordinate=116.307956%2C39.966622&coordinate=116.307956%2C39.966622&_osversion=6.0&radius=50000&_build=50&_platform=Android&_cityid=110100&_device=awiftb0%3A89%3A00%3A99%3A27%3Ae8&_version=3.8.3&page=2&channel=huijiachifan&size=10&_screen=1080x1810");
        out = new PrintWriter(conn.getOutputStream());
        out.print(parameterbulider.toString());
        out.flush();
        reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));
        String line = null;
        while ((line = reader.readLine()) != null) {
            responseBuilder.append(line);
        }
        reader.close();
        String result = responseBuilder.toString();
        return result;
    }