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;
}
}

性能方面：

HttpURLConnection的访问速度比HttpClient要快。