整理了HttpURLConnection与HttpClient的使用Demo

系统管理员 2022-05-16 11:13 201阅读 0赞

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 ##

![70][]

## 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<NameValuePair> 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<String,Object> 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<String,Object> params = new LinkedHashMap<String,Object>();
            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<Integer> step;
        public List<Integer> getStep() {
            return step;
        }
        public void setStep(List<Integer> 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<String,Object> 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<NameValuePair> params = new ArrayList<NameValuePair>();
            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<NameValuePair>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。

[70]: /images/20220516/e949ff78f90c42af9d8aa3f49387ef67.png