httpclient(一)

httpclient是apache封装的用于http请求的工具包，和python的requests类似。这里介绍一些简单功能的使用。后续根据需求也会慢慢扩展

使用HttpClient请求一个Http请求的步骤为：

（1）创建一个HttpClient对象模拟浏览器操作

　　CloseableHttpClient httpclient = HttpClients.createDefault();

　　CloseableHttpClient httpClient = HttpClientBuilder.create().build();

（2）创建一个Request对象

　　HttpGet get = new HttpGet(url);

　　HttpPost post = new HttpPost(url);

（3）头部参数处理

　　get.addHeader("1","2");

　　post.addHeader("1","2");

（4）参数处理

　普通data参数处理　

List<NameValuePair> formparams = new ArrayList<NameValuePair>();
formparams.add(new BasicNameValuePair(parameter[0],parameter[1]));
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formparams, Consts.UTF_8);
post.setEntity(entity);

 json格式处理

StringEntity entity = new StringEntity(json,"utf-8");
entity.setContentType("text/json");             
entity.setContentEncoding("UTF-8");             
post.addHeader("Content-type", "application/json;charset=UTF-8");
post.setEntity(entity);

（5）发送http请求，获得返回值

　　CloseableHttpResponse resp = httpClient.execute(post); 

　　CloseableHttpResponse resp = httpClient.execute(get); 

（4）处理response

　　HttpEntity httpEntity = resp.getEntity();　

　　String result = EntityUtils.toString(httpEntity, "utf-8");

（5）关闭HttpClient

　　httpClient.close();

package apitest;

import java.io.IOException;
import java.text.ParseException;

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

public class TestHpptClient {
    public static void main(String[] args) {
        doGetTestOne();
    }


    public static void doGetTestOne() {
        // 获得Http客户端(可以理解为:你得先有一个浏览器;注意:实际上HttpClient与浏览器是不一样的)
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        //创建一个Request对象
        HttpGet httpGet = new HttpGet("http://118.24.13.38:8080/goods/UserServlet?method=loginMobile&loginname=test1&loginpass=test1");
 
        // 响应模型
        CloseableHttpResponse response = null;
        try {
            // 由客户端执行(发送)Get请求
            response = httpClient.execute(httpGet);
            // 从响应模型中获取响应实体
            HttpEntity responseEntity = response.getEntity();
            System.out.println("响应状态为:" + response.getStatusLine());
            if (responseEntity != null) {
                System.out.println("响应内容长度为:" + responseEntity.getContentLength());
                System.out.println("响应内容为:" + EntityUtils.toString(responseEntity));
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                // 释放资源
                if (httpClient != null) {
                    httpClient.close();
                }
                if (response != null) {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }



}