整理了HttpURLConnection与HttpClient的使用Demo

HttpURLConnection与HttpClient是java目前较为常用的访问HTTP的api接口的方法。

自己将这两种方法整理为demo，在此保存。

Demo目录

Connection类

package com.Util.connection;

import org.apache.http.HttpEntity;
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.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;

/**
 *访问进行api
 */
public class Connection {

    /**
     * 使用HttpClient的Get方式访问api
     * 获得返回信息
     * @param url
     * @return
     */
    public String getResponseByHttpClientByGet(String url){
        String response = "";//存储返回信息
        CloseableHttpClient httpClient = null;//HttpClient实例
        HttpGet httpGet ;//Get方式提交
        CloseableHttpResponse httpResponse = null;//创建接收返回信息对象

        try {
            httpClient = HttpClientBuilder.create().build();//创建HttpClient实例
            httpGet = new HttpGet(url);//Get方式提交
            httpResponse= httpClient.execute(httpGet);//接收返回信息对象

            if (httpResponse.getStatusLine().getStatusCode()==200){//验证状态码
                HttpEntity entity = httpResponse.getEntity();//调用getEntity()方法获取到一个HttpEntity实例
                response = EntityUtils.toString(entity,"utf-8");//存储返回信息
            }else {
                throw new Exception("接收状态码异常");
            }

        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally { //关闭连接
            try {
                if (httpClient != null){
                    httpClient.close();
                }
                if (httpResponse != null) {
                    httpResponse.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return response;
    }

    /**
     *使用HttpClient的Post方式访问api
     * 获得返回信息
     * @param url
     * @param params
     * @return
     */
    public static String getResponseByHttpClientByPost(String url , List params){
        String response = "";//存储返回信息
        CloseableHttpClient httpClient = null;//HttpClient对象
        HttpPost httpPost ;//POST请求:
        CloseableHttpResponse httpResponse = null;//存储返回信息对象
        UrlEncodedFormEntity urlEncodEntity ;

        try {
            httpClient = HttpClientBuilder.create().build();//创建HttpClient实例
            httpPost = new HttpPost(url);//POST请求实例
            urlEncodEntity = new UrlEncodedFormEntity(params,"utf-8");
            httpPost.setEntity(urlEncodEntity);//将参数保存到HttpPost
            httpResponse = httpClient.execute(httpPost);//创建返回信息实例

            if (httpResponse.getStatusLine().getStatusCode()==200){//取出服务器返回的状态码，等于200就说明请求和响应成功
                HttpEntity entity = httpResponse.getEntity();//调用getEntity()方法获取到一个HttpEntity实例
                response = EntityUtils.toString(entity,"utf-8");//用EntityUtils.toString()这个静态方法将HttpEntity转换成字符串,防止服务器返回的数据带有中文,所以在转换的时候将字符集指定成utf-8就可以了
            }
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
                try {//关闭连接
                    if (httpClient != null){
                        httpClient.close();
                    }
                    if (httpResponse != null){
                        httpResponse.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
        }
        return response;
    }

    /**
     * 使用HttpURLConnection的Post方式访问api
     * @param serverUrl
     * @return
     */
    public static String getResponseByHttpURLConnectionByPost(String serverUrl){
        URL url = null;
        HttpURLConnection connection = null;
        BufferedReader reader = null;

        try {
            url = new URL(serverUrl);//获取访问地址URL
            connection = (HttpURLConnection) url.openConnection();// 2. 创建HttpURLConnection对象
            /* 设置请求参数等 */
            connection.setRequestMethod("POST");// 请求方式  // 超时时间
            connection.setConnectTimeout(3000);
            connection.setDoOutput(true);// 设置是否输出
            connection.setDoInput(true); // 设置是否读入
            connection.setUseCaches(false); // 设置是否使用缓存
            connection.setInstanceFollowRedirects(true); // 设置此 HttpURLConnection 实例是否应该自动执行 HTTP 重定向
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");// 设置使用标准编码格式编码参数的名-值对
            connection.connect();// 连接
            // 从连接中读取响应信息
            int code = connection.getResponseCode();
            String msg = "";
            if (code == 200) {
                reader = new BufferedReader( new InputStreamReader(connection.getInputStream()));
                String line;
                while ((line = reader.readLine()) != null) {
                    msg += line + "\n";
                }
                reader.close();
            }
            // 5. 断开连接
            connection.disconnect();

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return reader.toString();
    }

    /**
     * 使用HttpURLConnection的Get方式访问api
     * @param serverUrl
     * @return
     */
    public static String getResponseByHttpURLConnectionByGet(String serverUrl){
        URL url = null;
        HttpURLConnection connection = null;
        BufferedReader reader = null;
        try {
            url = new URL(serverUrl);//获取访问地址URL
            connection = (HttpURLConnection) url.openConnection();// 2. 创建HttpURLConnection对象
            /* 设置请求参数等 */
            connection.setRequestMethod("GET");// 请求方式  // 超时时间
            connection.setConnectTimeout(3000);
            connection.setDoOutput(false);// 设置是否输出
            connection.setDoInput(true); // 设置是否读入
            connection.setUseCaches(true); // 设置是否使用缓存
            connection.setInstanceFollowRedirects(true); // 设置此 HttpURLConnection 实例是否应该自动执行 HTTP 重定向
            connection.connect();// 连接
            // 从连接中读取响应信息
            int code = connection.getResponseCode();
            String msg = "";
            if (code == 200) {
                reader = new BufferedReader( new InputStreamReader(connection.getInputStream()));
                String line;
                while ((line = reader.readLine()) != null) {
                    msg += line + "\n";
                }
                reader.close();
            }
            // 5. 断开连接
            connection.disconnect();

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return reader.toString();
    }
}

注：

ConnectionRequest类与ConnectionResponse类是对应参数的实体类，我的Demo里所有的参数是通过Map的方式直接传参，未用到该实体类，这样大部分的api访问都可使用该demo的方法去访问。

ConnectionUtil类

package com.Util.connection;

import java.util.Map;

/**
 *工具
 */
public class ConnectionUtil {

    //将map里的参数变成像 showapi_appid=###&showapi_sign=###&的样子
    public static String urlencode(Map data) {
        StringBuffer sb = new StringBuffer();
        int j= 1;
        for (Map.Entry i : data.entrySet()) {
            sb.append(i.getKey()).append("=").append(i.getValue());

            if (j == data.size())  return sb.toString();
            sb.append("&");
            j++;
        }
        return sb.toString();
    }
}

Test类

package com.Util.connection;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
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.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.DefaultHttpClient;
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.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

public class test {
    public static void main(String[] args) throws IOException {

        //接口地址
        String requestUrl = "http://route.showapi.com/60-27";

        //params用于存储要请求的参数
        Map params = new LinkedHashMap();
        params.put("origin","120.173513,30.182344");
        params.put("destination","120.17971,30.187726");
        params.put("size","3");
        params.put("key","30bfe2cb061e2abb25fc2af3fab04227");

        //调用httpRequest方法，这个方法主要用于请求地址，并加上请求参数
        String urlInfo = "https://restapi.amap.com/v4/direction/truck";
        String url = "https://restapi.amap.com/v4/direction/truck?"+Connect.urlencode(params);

        //String url = "https://restapi.amap.com/v4/direction/truck?origin=120.173513,30.182344&destination=120.17971,30.187726&size=3&key=30bfe2cb061e2abb25fc2af3fab04227";
        //String result =Connect.getResponse(url);
        //System.out.println(result);

        String response = Connect.getResponseByHttpClient_Post(url);
        //String response = Connect.getResponseByHttpClient_Get(url);
        System.out.println(response);

    }
}

class Array{
    int i;
    String var;

    private List step;
    public List getStep() {
        return step;
    }
    public void setStep(List step) {
        this.step = step;
    }
}

class Connect{

    //将map里的参数变成像 showapi_appid=###&showapi_sign=###&的样子
    public static String urlencode(Map data) {
        StringBuffer sb = new StringBuffer();
        int j= 1;
        for (Map.Entry i : data.entrySet()) {
            sb.append(i.getKey()).append("=").append(i.getValue());

            if (j == data.size())   return sb.toString();
            sb.append("&");
            j++;
        }
        return sb.toString();
    }

    public static String connectURL(String dest_url, String commString) {
        String rec_string = "";
        URL url = null;
        HttpURLConnection urlconn = null;
        OutputStream out = null;
        BufferedReader rd = null;
        try {
            url = new URL(dest_url);
            //HttpURLConnection对象不能直接构造，需要通过URL类中的openConnection()方法来获得。
            urlconn = (HttpURLConnection) url.openConnection();
            urlconn.setReadTimeout(1000 * 30); // 设置超时时间
            urlconn.setRequestMethod("POST");// 设置请求方式
            urlconn.setDoInput(true);// 设置是否从httpUrlConnection读入
            urlconn.setDoOutput(true);// 设置是否向HttpURLConnection输出
            out = urlconn.getOutputStream();// 添加 附加数据，只有POST方式才可以添加，所以，使用此方法后，会自动把方法设置为POST
            out.write(commString.getBytes("UTF-8"));
            out.flush();
            out.close();
            rd = new BufferedReader(new InputStreamReader(urlconn.getInputStream(),"UTF-8"));
            StringBuffer sb = new StringBuffer();
            int ch;
            while ((ch = rd.read()) > -1)
                sb.append((char) ch);
            rec_string = sb.toString();
        } catch (Exception e) {

            return "";
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (urlconn != null) {
                    urlconn.disconnect();
                }
                if (rd != null) {
                    rd.close();
                }
            } catch (Exception ignored) {

            }
        }
        return rec_string;
    }


    //连接及解析高德地图
    public static String getResponse(String serverUrl){
        //用JAVA发起http请求，并返回json格式的结果
        StringBuffer result = new StringBuffer();
        try {
            //建立连接
            URL url = new URL(serverUrl);
            URLConnection conn = url.openConnection();
            //调用api，并返回流
            BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));
            //循环输出流获取流内信息
            String line;
            while((line = in.readLine()) != null){
                result.append(line);
            }
            in.close();

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result.toString();
    }

    //利用HttpClient进行http的api调用
    //利用Post提交
    public static String getResponseByHttpClient_Post(String serverUrl) throws IOException {
        PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();//对HttpClient的配置
        cm.setMaxTotal(200);// 最大连接数
        cm.setDefaultMaxPerRoute(20);//每个路由基础的连接

        HttpClient httpClientDeprecated = new DefaultHttpClient();//DefaultHttpClient方式
        HttpClient httpClientHttps = HttpClients.custom().setConnectionManager(cm).build();
        HttpClient HttpClient = HttpClientBuilder.create().build();
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();//HttpClient jar在4.3版本以后，DefaultHttpClient 被 deprecated(不推荐)，用HttpClientBuilder替代
        String response = "";
        HttpPost httpPost = new HttpPost(serverUrl);//POST请求:

        List params = new ArrayList();
        params.add(new BasicNameValuePair("origin","120.173513,30.182344"));
        params.add(new BasicNameValuePair("destination","120.17971,30.187726"));
        params.add(new BasicNameValuePair("size","3"));
        params.add(new BasicNameValuePair("key","30bfe2cb061e2abb25fc2af3fab04227"));
        UrlEncodedFormEntity urlEncodEntity = new UrlEncodedFormEntity(params,"utf-8");
        httpPost.setEntity(urlEncodEntity);

        CloseableHttpResponse httpResponse = httpClient.execute(httpPost);//发送请求,并返回的所有信息，保存在HttpResponse里面
        System.out.println(httpResponse.getProtocolVersion());//协议版本
        System.out.println(httpResponse.getStatusLine().toString());//状态行信息
        System.out.println(httpResponse.getStatusLine().getStatusCode());//状态码
        System.out.println(httpResponse.getStatusLine().getReasonPhrase());//状态码的解释

        if (httpResponse.getStatusLine().getStatusCode()==200){//取出服务器返回的状态码，等于200就说明请求和响应成功
            HttpEntity entity = httpResponse.getEntity();//调用getEntity()方法获取到一个HttpEntity实例
            response = EntityUtils.toString(entity,"utf-8");//用EntityUtils.toString()这个静态方法将HttpEntity转换成字符串,防止服务器返回的数据带有中文,所以在转换的时候将字符集指定成utf-8就可以了
        }
        httpResponse.close();
        httpClient.close();

            return response;
        }

    //利用HttpClient进行http的api调用
    //利用Get提交
    public static String getResponseByHttpClient_Get(String serverUrl) throws IOException {
        HttpClient httpClientDeprecated = new DefaultHttpClient();//DefaultHttpClient方式
        HttpClient httpClientBuilder = HttpClientBuilder.create().build();//HttpClient方式 jar在4.3版本以后，DefaultHttpClient 被 deprecated(不推荐)，用HttpClientBuilder替代
        String response = "";
        HttpGet httpGet = new HttpGet(serverUrl);

        HttpResponse httpResponse = httpClientBuilder.execute(httpGet);
        if (httpResponse.getStatusLine().getStatusCode()==200){
            HttpEntity entity = httpResponse.getEntity();//调用getEntity()方法获取到一个HttpEntity实例
            response = EntityUtils.toString(entity,"utf-8");
        }
        httpClientBuilder.getConnectionManager().shutdown();//关闭连接
        //Get方式与Post方式最大的区别为:
        //Post方式需要list的集合来存放api所需要的参数,（注意:HttpPost方式也可以用URL方式传参）
        //Get方式直接在访问路径内附带参数即可，（注意:HttpGet方式也可以用Body方式传参）

        return response;
    }
}

注：

该test类是我自己在理解HttpURLConnection与HttpClient时写的test。