服务端实现http发送请求（HttpURLConnection与HttpClient区别及使用）

区别

1、HttpURLConnection是java的标准类，没有做封装，用起来比较原始

2、HttpClient是开源框架，封装了访问HTTP的请求头、参数、内容体、响应等；HttpURLConnection中的输入输出流操作，在这个接口中被统一封装成了HttpPost（HttpGet）和HttpResponse。这样，减少了操作的繁琐性。

下面分别给出HttpURLConnection和HttpClient实现GET、POST请求示例，作为学习。

（1）HttpURLConnection实现GET

   

 package com.jingchenyong.test;
     
    import java.io.BufferedReader;
    import java.io.InputStreamReader;
    import java.net.HttpURLConnection;
    import java.net.URL;
     
    public class Test_HttpURLConnection_GET
    {
        
        public static void main(String[] args) throws Exception
        {
            String urlString="http://15.6.46.35:8080/platform/index.html";
            URL url=new URL(urlString);
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            conn.setRequestProperty("Accept-Charset", "UTF-8");
            conn.setRequestProperty("connection", "keep-Alive");
            conn.setRequestMethod("GET");
            conn.connect();
            
            int code=conn.getResponseCode();
            System.out.println(code);
            //把流转为字符串方式一
            //String  result=IOUtils.toString(conn.getInputStream(),"UTF-8");
            //把流转为字符串方式二
            BufferedReader br=new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));
            String result="";
            String tmp="";
            while((tmp=br.readLine())!=null){
                result=result+tmp;
            }
            System.out.println(result);
            //关闭流和连接
             
        }
        
    }

（2）HttpURLConnection实现POST

   

 package com.jingchenyong.test;
     
    import java.io.BufferedOutputStream;
    import java.net.HttpURLConnection;
    import java.net.URL;
     
    import org.apache.commons.io.IOUtils;
    import org.apache.commons.lang.StringUtils;
     
    import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.JSONObject;
     
    public class Test_HttpURLConnection_POST
    {
        
        public static void main(String[] args)
            throws Exception
        {
            //设置连接
            String urlString = "http://15.6.46.37:9200//henry/henry/_search";
            URL url = new URL(urlString);
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            conn.setRequestProperty("Accept-Charset", "UTF-8");
            conn.setRequestProperty("connection", "keep-Alive");
            conn.setRequestMethod("POST");
            conn.setDoInput(true);
            conn.setDoOutput(true);
            conn.connect();
            String jsonstring = getJOSNString();
            if (StringUtils.isNotBlank(jsonstring))
            {
                /**
                 * post提交方式一
                 */
               /* OutputStream os = conn.getOutputStream();
                BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os));
                writer.write(jsonstring);
                writer.flush();
                writer.close();*/
                BufferedOutputStream out = new BufferedOutputStream(conn.getOutputStream());
                out.write(jsonstring.getBytes());
                out.flush();
                out.close();
                
                //流转字符串的另一种方式见GET方式
                String  result=IOUtils.toString(conn.getInputStream(),"UTF-8");
                System.out.println(result);
                
                //注意关闭流和连接，这里省略
            }
        }
        
        public static String getJOSNString()
        {
            JSONObject jsonobject = new JSONObject();
            JSONObject jsonobject1 = new JSONObject();
            JSONObject jsonobject2 = new JSONObject();
            jsonobject2.put("name", "jingchenyong");
            jsonobject1.put("match", jsonobject2);
            jsonobject.put("query", jsonobject1);
            String jsonstring = JSON.toJSONString(jsonobject);
            return jsonstring;
        }
    }

（3）HttpClient实现GET

   

package com.jingchenyong.test;
     
    import java.io.BufferedReader;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.Map.Entry;
     
    import org.apache.commons.collections.MapUtils;
    import org.apache.http.client.config.RequestConfig;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.client.utils.URIBuilder;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
     
    public class Test_HttpClient_GET
    {
        
        public static void main(String[] args) throws Exception
        {
            String url="http://15.6.46.35:8080/platform/index.html";
            URIBuilder builder = new URIBuilder(url);
            CloseableHttpClient httpClient = HttpClients.createDefault();
            Map<String,Object> map=getMap();
            if(MapUtils.isNotEmpty(map)){
                for(Entry<String,Object> entry:map.entrySet()){
                    builder.addParameter(entry.getKey(), String.valueOf(entry.getValue()));
                }
                url=builder.build().toString();
            }
            HttpGet get=new HttpGet(url);
            // 增加超时设置
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(1000).build();
            get.setConfig(requestConfig);
            
            //发送GET请求
            CloseableHttpResponse response=httpClient.execute(get);
            //获取状态码
            System.out.println(response.getStatusLine().getStatusCode());
            //把结果流转为字符串方式一
            /*
            String result=IOUtils.toString(response.getEntity().getContent());
            System.out.println(result);
            */
            //把结果流转为字符串方式二
            StringBuilder reMsgBuider = new StringBuilder();
            InputStream in = response.getEntity().getContent();
            BufferedReader reader = new BufferedReader(new InputStreamReader(in, "UTF-8"));
            String msg = null;
            // 读取返回消息体
            while ((msg = reader.readLine()) != null) {
                reMsgBuider.append(msg);
            }
            String result = reMsgBuider.toString();
            System.out.println(result);
            //关闭流和连接
            
        }
        public static Map<String,Object> getMap(){
            Map<String,Object> map=new HashMap<String,Object>();
            //map.put("name", "jingchenyong");
            //map.put("age", 26);
            return map;
        }
    }

（4）HttpClient实现POST

   

 package com.jingchenyong.test;
     
    import org.apache.commons.io.IOUtils;
    import org.apache.http.client.config.RequestConfig;
    import org.apache.http.client.methods.CloseableHttpResponse;
    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.HttpClients;
    import org.apache.http.util.EntityUtils;
     
    import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.JSONObject;
     
    public class Test_HttpClient_POST
    {
        
        public static void main(String[] args) throws Exception{
            String jsonstring=getJOSNString();
            RequestConfig config = RequestConfig.custom().setSocketTimeout(30000).setConnectTimeout(30000).build();
            CloseableHttpClient client = HttpClients.custom().setDefaultRequestConfig(config).build();
            HttpPost post = new HttpPost("http://15.6.46.37:9200//henry/henry/_search");
            //填充post体
            post.setEntity(new StringEntity(jsonstring,"UTF-8"));
            CloseableHttpResponse response = client.execute(post);
            System.out.println("状态码为："+response.getStatusLine().getStatusCode());
            //方式一
            //System.out.println("获取的结果为(获取方式一)："+IOUtils.toString(response.getEntity().getContent()));
            //方式二 见GET
            //方式三
            System.out.println("获取的结果为(获取方式二)："+EntityUtils.toString(response.getEntity(), "UTF-8"));
            
        }
        public static String getJOSNString()
        {
            JSONObject jsonobject = new JSONObject();
            JSONObject jsonobject1 = new JSONObject();
            JSONObject jsonobject2 = new JSONObject();
            jsonobject2.put("name", "jingchenyong");
            jsonobject1.put("match", jsonobject2);
            jsonobject.put("query", jsonobject1);
            String jsonstring = JSON.toJSONString(jsonobject);
            return jsonstring;
        }
    }